Installing a flat roof (PVC single ply roofing membrane in this case) can be a pretty straight forward process, or a very confusing endeavor because each component must be installed in order of events. Otherwise the system my not work the way it should. Of course there is an installation spec manual from IB roofs, which we always keep handy, and actually had to use it once or twice. But this manual only shows particular flashing detail or a general way of how membrane and insulation ought to be installed. It can’t possibly cover all the specifics of the roof installation that come up in the field.

Flat roof installation – mechanically attached assembly:

A reinforce PVC single ply roof allows installers a choice of installing the roof in a fully adhered assembly (sheets of membrane glued to the insulation) or a mechanically attached assembly where each sheet or roll of the roofing material is screwed to the roof deck substrate with heavy duty, corrosion resistant roofing fasteners, and barbed plates. Each roll is screwed to the roof deck on one side, and then the next roll, overlaps a row of screws, and is welded to the first roof, right next to the screws. Then the process continues in the same manner until the whole roof is covered by the membrane.

As you can see in the roof installation picture above the narrow roll of membrane ins installed around roof perimeter and wider rolls are in place, and are ready to be installed. However, before you get to this point, there is a lot of prep work that has to me done first, and the actual membrane installation is the easy part.

Lets start looking at the prep work, and the in which order things actually happen.

Flat roof installation – prep work – insulation, wood nailer and penetration flashing.

PVC Roofing is a very durable and long lasting flat roofing material. However it should never we in direct contact with any oil and asphalt (also oil) products, and since most other roofing materials are made with oil or asphalt, we always install a protection layer between PVC membrane and either old roof or the roof deck. We usually use insulation to protect membrane from being in contact with asphalt and also from deck fastener punctures. Roof insulation also serves its primary purpose of improving thermal insulation properties of your roof.

Before we install insulation though, we first install a perimeter wood nailer, that serves as a rigid nailing base for the PVC-coated drip edge. Once wood nailer is in place, we lay out the insulation sheets and fasten them to the roof deck, using FM Global 60 or 90 mph wind rating standard – 8 or 10 plates + fasteners per 8×4 feet insulation board (although this is unnecessary, since it is a mechanically attached system). Once the wood nailer and insulation are in place we install one or more row of perimeter half sheet, which is a 3 foot wide roll of membrane, vs and standard 6 feet width for field rolls. The perimeter half sheet is installed to prevent wind uplift, and is fastened either 12″ o.c. or 6′ o.c. (for high wind areas).

Flat roofing – tapered insulation:

If there is a ponding water situation, the fastest and most cost-effective way to solve the ponding is to install a so called tapered insulation system which creates slight roof pitch, which helps diver the water in required direction and improves roof drainage.

Tapered insulation is basically the same thing as extruded PolyISO insulation with a fiberglass facing. The only difference is that tapered insulation is wider along one edge and narrower along the other. Tapered insulation system can have a roof slope ranging from 1/8″ per one foot run, to 1/2″ rise per one foot run or more. Normally we use a 1/4″ tapered insulation system which raises roof level 1″ for every 4×4′ insulation piece.

Flat roof installation – drip edge detail:

As we mentioned the perimeter half sheet is installed along roof edges, and fastened on the inside with screws and plates – what is holding the half sheet along its outer edge? Well, this is the question that homeowners often ask me. The way IB PVC roof system is designed, allows us to attach the outer edge either directly to the drip edge or run in over the roof edge by a couple of inches, nail it to the fascia board and install a drip edge metal over the membrane.

Both ways are acceptable, but most of the time we use the second method – especially in high winds area. Once the roofing material is installed and flipped down, over the edge of the roof, we install 10 foot sections of 22 ga PVC coated galvanized or stainless steel drip edge, and fasten it to the deck with the roofing screws, either 12″ or 6″ o.c. Then we weld a 5″ wide cover strip of the membrane to the roof and to the drip edge, to seal the screw holes and bake the whole detail water-tight.

Check out our video on how drip-edge metal is installed:

Once the 10-foot sections of drip-edge are installed, the joins are sealed using an aluminum tape and a PVC patch to mack the joint water-tight and protect the patch from metal expansion and contraction. After the joints are complete, the cover tape is welded to drip edge starter and the roof itself and its now time to do the rest of the roof.

As a side note, there are many options for drip edge detail. Although the most used drip edge is the 2 or 3″ wide face, white starter, you can also choose it to be as much as 8 or more inches wide as well as in gravel stop style (if you need divert water flow or prevent it from going over the edge of the roof.

Gravel stop drip edge has a 1″ bump-out, which stops water from spilling over, and makes it run down the roof – toward a drain or a gutter. Drip edge comes in two colors – white and dark bronze, and also can be painted any other color with acrylic paint. IB roofs also offers 16 oz. copper drip edge, with PVC material adhered to the flange, and can produce any style drip edge, with different angles, kick-in or kick-out face and in various widths.

Flat roof installation – field sheets, roof penetrations and roof to wall termination:

After all edge detail is complete, we install the field rolls of membrane and all penetration flashings, such as pipes, drains, HVAC / Skylight curbs, roof hatches, chimneys, etc.

IB Roof Systems produces wide variety of flashing accessories, which allow installers to quickly easily flash almost any roof penetration. Since all roof components are made of PVC, they are all welded together, and use of any adhesives or glues is completely eliminated, as well as most installation errors by roof mechanics.

All curb and up-the wall flashing is installed using two step process. First, the roof is terminated that the wall, and then a separate piece of membrane is installed up the wall and welded to the roof.

After the flashing is installed and welded to the roof, the inside or outside corner flashing is welded to make a permanent watertight joint.

All IB flashing accessories are made of 60-mil non-reinforced flashing membrane and can stretch to perfectly adhere to any shape of a penetration on the roof. Pipe flashings and drains have a reinforced flange to be welded to the roof.

Bellow is a video demonstrating the curb flashing installation around a skylight:

As you can see in the video, the roof penetration flashing is a very clean process, and a chance of a leak is minimum to non. Unlike flashing details on a rubber roof, where membrane cannot and should not be terminated at the base of the curb, due to high possibility of a leak caused by adhesive failure, the hot air welding process used in sealing overlaps and seams on a PVC roof, eliminates leaks as well as membrane pull-out caused by contraction of the roofing material in a cold weather.

Flat roof installation – special flashing details:

IB roof spec manual does not cover all installation details as in real world you often run into situations where you have to “improvise”, while your roof must still be watertight. One such example is the ridge vent detail on flat / low slope roofs such as shed dormers. While many low slope roofs are considered “flat”, they were built as sloped roofs with ridge / soffit ventilation in mind. However, many roofing contractors that install EPDM rubber roofs, block the ridge vent opening completely, to prevent roof leaks.

We’ve developed a special assembly method which allows us to still use the ridge vent, and keep the roof watertight. We run our roof up-to the ridge opening, weld additional strip of membrane, install a 2×4 wood to raise the level off the roof, flip the strip of membrane back and wrap the 2×4 with it. This prevents wind driven water from penetrating the roof, and ridge vent + ridge cap is installed on top, 2 inches up.

As you can see, IB PVC roof can be adjusted to virtually any type of flat roof, and roof penetrations. We recommend that you check out more roof installation videos on our Roofing Videos channel on YouTube.

You can see more examples of flat roof installations that we have done all over New England: Roofing in Massachusetts and roofs in Connecticut. We provide residential roofing and commercial roof installation services in all New England states. However most of our work takes place in MA, CT and RI.

Also, if you have a flat roof deck, that is leaking, check out our roof deck section, to learn more about IB roof installation on flat roof decks, patios, and balconies, using special slip-proof roofing material called IB DeckShield.

Many homes have an outside deck / patio over a living space, and so far, the solution to waterproof such roof decks was to install rubber membrane roof and a wooden deck on slippers over the rubber. On some older roofs, instead of a rubber roof, a Tar / Built-up roofing material is used for waterproofing. Problems with this assembly is first and foremost the roof leaks which often occur within few years of roof deck installation.

Often the seams on the roofing membrane pop open, or water starts to pool under the deck, and the only way for this water to drain is into your home. If you need to repair such roof deck, you will have to take the deck completely apart to seal the seams or redo the roof flashing, and then put the wooden deck back together.

Another issue is the cost of such roof deck (even without the high costs associated with roof repairs) – the rubber roof by itself is somewhat not expensive, but when you add the cost of a pressure treated wood deck (a fiber decking, mahogany or some other premium deck is rather rare, and most people do choose to go with PT wood), your roof deck ends up costing you a small fortune. Then you also have to install and seal the railing posts.

On a rubber roof, pieces of uncured flashing must be glued to the rubber roof and the post to make the post penetration watertight, and on a Tar / BUR roof, liquid tar or roof cement is used to seal around the post. Both rubber roof flashing and tar flashing around the post will begin to fail after 5-7 years, so once again to stop the roof leaks, you will have to disassemble the deck and repair the flashing.

IB Deck Shield – the long lasting, beautiful and cost effective solution for roof decks

IB Roof Systems saw the need for a long-lasting waterproofing membrane for roof decks, patios and balconies, and based an their excellent PVC roofing membrane, created a Deck Roofing product which will last for decades, is easy to repair (if such need arises) and has a special, slip-resistant, beautiful surface which make it possible to walk on this membrane, eliminating the need for a wooden deck over the membrane and making the whole roof seamless and watertight.

IB Deck Shield was created based on IB Roofs’ proven PVC roofing membrane, designed for flat roofs, and featuring hot air welded seams, which make membrane overlaps sealed permanently, ensuring long-lasting watertight roof. IB roofing membrane can withstand ponding water, and is an excellent choice for any flat roof. IB roofs also have a complete line of flashing accessories – inside and outside corner flashings, pipe flashing ranging in size from 1/4″ to over 12 inches, for extra wide exhaust pipes and furnace stacks. Because of fast and easy installation in all tight spots, any roof penetration can be flashed quickly and any installation defects are eliminated.

IB took it’s existing it’s existing PVC roof product (IB Flat Roof), and added a special surface to it, making it slip resistant, even when wet, and added a beautiful texture, which resembles small pebble surface often used as a swimming pool deck. All components of IB Deck Shield roof are color matching and will produce a uniform, great-looking final product.

IB Deck Shield roof installation:

Because IB Deck Shield is exposed to constant foot traffic, deck furniture, outside BBQ grills, etc., it must withstand all this abuse and last for many years without any leaks. To be able to do so, IB deck Shield is installed over a dense, moisture resistant substrate – DensDeck, which is attached to the roof deck.

Once DensDeck substrate is installed, all seams are taped and “plastered” with special joint compound to provide a universal, smooth surface, to which Deck Shield membrane is glued using either a water-based or solvent based adhesive (we use water based glue, as it is environmentally “safer” than solvent based product).

When a a joint compound cures, we apply a layer of IB water-based adhesive and lay down the IB Deck Shield membrane, which was previously aligned to be wrinkles free and to have exactly a 2″ overlap with the previous sheet of membrane. Once adhesive is applied and membrane is laid down, it is mechanically fastened at all roof to wall connections, but never in field.

After a few minutes, when adhesive cures, all seams are welded and it’s time to install roof to wall flashing as well as all pre-fabbed inside / outside corners, as well as flash all post penetrations. IB Roof manufactures special post flashings which can either be pre-welded or split and it is the choice of a contractor which one to use.

We prefer to use split post flashings – although the split post flashing requires more welding, it is actually easier to install split flashing rather then a welded flashing, because when we order them, we specify the post size – usually 3 5/8″ x 3 5/8″ (a standard 4×4′ railing post), and a welded flashing sits pretty tight around the post so it is rather difficult to pull it all the way down.

Durability of IB DeckShield flat roof decks:

Once all DensDeck is installed, all DeckShield is glued down, seams welded and all flashings are installed, the roof is complete, and now you have a durable, completely water-tight roof deck, where you can spend nice summer days, invite your friends over for BBQ, and not worry about roof leaks any more. IB DeckShield is VERY durable, and very resistant to puncture damage. Because it is glued to the DensDeck substrate, the surface under it is very hard and most sharp objects that fall on this roof will bounce off leaving very little or no damage – we accidentally dropped sharp tin snips, that just bounce off and did not cause any damage.

Of course you want to be careful with your new roof and not drop any sharp objects purposely, but small accidents do happen, and you can be confident that IB DeckShield will withstand all normal wear and tear – foot traffic and most accidental drops, which would usually puncture a flat roof such as rubber roofs.

If your roof is damaged – in most cases it should be leaking for a long time, as membrane is glued to the substrate and even if some water gits in, it won’t be able to spread and leak inside your home. It is also very easy repair IB Deck Shield roof – a small patch of color-matching membrane will be welded over damaged area, making the repair virtually invisible, unless looked at from close distance. IB DeckShield roof will remain weldable for decades, just like other IB Flat roofing products.

Roof deck prices – how much does IB DeckShield cost to install?

IB DeckShield is a premium flat roofing product and is rather expensive by itself. However, when you consider the alternative of a rubber roof with a PT wooden deck over it, IB DeckShield will usually be less expensive, as PT wood deck will add a significant amount to the total roof deck cost.

Because IB DeckShield installation is rather complicated and involved, it will cost more than the flat roof prices provided by our roofing calculator. IB Deck Shield takes considerably longer to install than regular IB flat roofs, and costs a lot more than standard 50-mil or even 80-mil IB roofing membrane. Therefore installation prices per sq. ft. of your roof deck will be higher than those of an 80 mil roof deck option (eg. flat roof deck in Wellesley, MA)

Price of IB Deck Shield installation will also depend or roof difficulty, number of roof penetrations and whether the existing roof needs to be removed. In case of a roof removal, the roof deck must be installed in sections, and sealed at the end of each work day, to prevent roof leaks from overnight rains.

IB Roof Deck prices:

A basic price to install IB DeckShield starts at $14-15 per sq. ft. (assuming that your roof deck is approximately 200-300 sq. ft., which is what most roof decks are), and includes a 1/4″ DensDeck Substrate, with all joints sealed using joint compound, and up to 5 post flashing penetrations. All other flashing and penetration details will be priced assuming other aspects of your roof, and the entire project.

Roof tear-off will be priced in a range of $300+ per 100 sq. ft. of roof area, plus cost of the dumpster. Reason for this price structure is as follows: Roof decks are usually rather small, but the tear off greatly intensifies the installation difficulty and slows down the overall process. Also, we separate dumpster fees, as on a small roof we would still need the smallest (10 or 15 yards) dumpster which costs about $300.

To give you and example – it took us about 5 days to complete the roof in the first picture on this page, with 4-5 guys working 8-10 hours per day. The roof size there is approximately 1200 sq. ft. So assume that 4-5 guys removed and installed about 240 sq. ft. of roof in 1 day.

The pricing above is approximate and reflects general price stricture that we use fordeck roofs installation in Massachusetts and the rest of New England states (Roofs in CT, RI, NH, ME and VT).

We will price each roof deck separately, but this will provide you with a pretty accurate pricing guide-lines, so you would know how much to expect to pay for IB DeckShield roof.

As a comparison, a rubber roof would cost you $8-10 per sq. ft. plus the cost of PT wooden deck which can range from $13-20 per sq. ft., often without the material costs.

Additional roof decks and flat roofing resources:

Roof deck installation using 80-mil IB PVC roof with a wooden deck over it.

RoofDecks.org – general information about roofing materials, roof deck prices and installation methods of waterproofing products for roof decks, balconies and patios.

Flat Roofing – informational resource about flat roofing materials – Learn about EPDM Rubber roofing, PVC and TPO roofs and Tar & Gravel, Modified Bitumen and other Built-Up roofs.

Roof calculator – estimate roofing prices in your state for different roofing materials – asphalt shingles, metal roofs, and various flat roofing membranes. Learn how contractors price their roofs and pros & cons different roofing materials. Find out how to measure and estimate a roof using extensive step-by-step roof estimating guide and roofing calculator software.

The truth is, there is a solution that will keep your home, probably your biggest investment, water tight for decades to come. The flat roof you can truly forget about, and the one that will actually save you money on ever-rising energy costs.

If you have a flat roof deck you can choose between IB DeckShield or a conventional 80-mil IB roof with wooden deck and railing system to solve your leaks problems and create a permanent water-tight roof-top patio.

When you want the looks of an Architectural Shingles and unsurpassed reliability of IB Roof, IB Traditions gives you both!

IB Cool Flat Roof – The Best flat roofing for your Home!

IB roof has its roots in commercial flat roofing, where requirements and expectations of building products are much higher than in residential market. In fact IB Roof has been chosen as the roofing choice for Hospitals, Airports and Universities through-out the country, where leaking roof is not an option. Many of these roofs installed over 25 years ago are still performing well, without any leaks.

Ice Dam leaks and poor ventilation:

Most low sloped roofs in the northern United States have Ice Dams, which cause roof leaks and expensive roof repairs as well as cosmetic interior repairs of ceilings, walls, carpets and wooden floors. Those are the damages that you can actually see. Ice dams also create invisible structural damages which you can’t find until you open up ceilings and wall. These damages are extremely expensive to repair, as it would require to hire interior remodelers to fix structural damages, outside and inside walls, electrical systems, plumbing, etc.

Ice Dams in a nutshell: Ice dams are caused by poor attic ventilation and heat loss from inside your living space. Large piles of snow will accumulate on your roof after a snow storm. If your attic is improperly insulated and ventilated, the warm air escaping from your living area into the attic, will melt the snow. The water from melting snow will run down the roof and refreeze, usually along the eaves of of your roof. These are Ice Dams. The more snow is melting the bigger Ice Dams you have. After some time, the ice dams become so big, that the melting water cannot travel downward anymore, so it starts to travel upward underneath the roof shingles or rolled roofing seams. As it freezes under the roof, warm air melts it, and it slowly starts to drip inside the attic, causing all of the above and below mentioned problems.

It becomes a vicious cycle were more heat loss creates more ice dams, which causes more damages to structural walls and insulation, destroying your home from inside, increasing your energy-related expenses and causing more heat loss, which creates bigger ice dams…

Negative effect cause by Ice dams, and which many homeowners neglect to address is the wet insulation in the attic and inside walls. When insulation gets wet, you loose insulating value, so your energy costs increase, as heat loss in the winter drives up your heating bill. Same happens in the summer with cooling. Also, mold begins to grow in the attic and inside walls, which cause and/or aggravates allergies, asthma and other respiratory illnesses.

Solution to Ice Dams problems on low-slope roofs:

IB roofing membrane is perfect way to eliminate Ice Dams on a low slope roof, as it is a seamless blanket over entire roof. Hot air welded seams prevent water from backing up and re-freezing as is the case with shingles and rolled asphalt roofing, there-fore eliminating the effects of Ice Dams. Also, Most of the snow will actually slide off the IB roof, thus there will be a minimal Ice and Snow accumulation along the eaves.

Additionally, we’ve designed a special Ridge Vent system which we use on every low-sloped roof with ridge/soffit ventilation in place. This system prevents the wind driven water form entering your attic space through the holes in the ridge vent, while allowing the warm air to escape the attic.

Now you too can have this outstanding roof on installed on your home. IB make the perfect choice for any residential flat and low-slope roof. IB roof will give you years of worry-free service, and make your home more energy efficient, as well as transferable Lifetime Warranty! IB will also add beauty and usability to your home with its specialty Traditions & DeckShield membranes.

Traditions Classic: Printed Shingle Pattern

If you have a low-pitched roof which is flatter than a minimum required for a conventional roofing, but is still visible from the ground, IB has the perfect solution – ‘Traditions Classic’.

Traditions is a single ply membrane that was designed to eliminate the problems associated with conventional asphalt shingle, but will give you the looks of an architecturally designed shingle roof that fits your home.
Traditions Classic carries a Lifetime Material Warranty and is also fade resistant and is perfect Massachusetts, Rhode Island and Connecticut climate. It outperforms any shingle roof from any manufacturer.

Traditions – Design and appearance:

Traditions Classic gives you the perfect combination of integrity and beauty. It takes the excellent qualities of Industrial Grade IB flat roofing membrane and an outstanding looks of asphalt shingles with a choice of three popular colors:

Sierra Vista: Light Brown color will give you a perfect combination with red brick homes as well as other red, tan and brown shades of conventional siding.

Stony Ridge: Grey color – will blend perfectly with grey and most other colors.

Mountain Spruce: Great for suburban areas, and will bled well with background forest, as well as bushes and trees surrounding your home.

Traditions – Maintenance and Life-cycle:

A good roof is the one you can forget about and Traditions classic is no different. Traditions Classic is virtually maintenance free and is specially designed for low sloped roofs. The high quality membrane resists mold, mildew, algae, chemicals and ultraviolet rays, and will continue to look great on your home for years to come – guaranteed!

If you have a leaking rubber roof in Massachusetts, Connecticut or Rhode Island we can repair your rubber roof at a relatively low cost, using only the best materials that rubber systems have. Example of such materials are peel-and-stick flashing and seam tapes. We do not use black rubber glue as it is outdated, and leaks much faster.

Quick Navigation:

• Why homeowners should avoid rubber roofing – The truth of about residential flat roofing market and why you should stay away from rubber, and carefully choose your roofing contractor.
• Alternatives to rubber roofing – Find out what other, better flat roofing products are available for a similar cost, but without the EPDM’s inherited problems.
• Residential rubber roofing – Learn why rubber roofs should NOT be used on a roof of your home.
• Commercial rubber roofing – Limitations of EPDM rubber in the commercial flat roofing applications.
• Why rubber roofs are so popular – Quick history of EPDM rubber in US flat roofing market, and key to its popularity

Truth about residential flat roofing market and contractors.

This rubber roof is just 1 year old, and has been leaking since day one, until we replaced it with a lifetime IB PVC flat roofing membrane.

Rubber Roof Contractors: It is unfortunate, but most residential flat roofs are installed by roofing contractors that specialize in asphalt shingles. Since they can easily purchase rubber roofing materials from their roofing supply warehouse, and are not required to be certified installers, nor do they need any special training or equipment, they will often undertake such projects to keep their crews busy.

Incorrectly installed EPDM roof in Quincy, MA – rubber glued right over shingles:

The truth is such that to get a quality, rubber roof installed, it usually has to be done by a commercial roofing company that specializes in flat roofing. However it is often the policy of such companies not to work with residential customers, for which there are many reasons. These contractors work with large commercial and institutional customers, employ union workers who are trained roof mechanics specialized in their particular niche. For example, a commercial roofing contractor will have separate crew doing metal roofing or slate – these guys are “roofers”, and yet another crew doing flat roofing ONLY – these are “roof mechanics”.

A residential roofing contractor, usually employees just roofers, who are good at what they do all day long – installation of asphalt shingle roofs, and often do not have a clue about how flat roofs work. When they get a potential client with a flat roof, they go to their supplier, as what supplier has for flat roof, and the salesman at the supply warehouse TEACHES the roofer how to install EPDM rubber. This is not creative fiction or product of my imagination – I see this happening nearly every time, when I come in to get something.

“Trained rubber roofing installers”: If you are lucky, you may get a roofer that has received some sort of training about rubber roof installation. For example, one of my suppliers, provides installation training programs for their roofing contractors who install only asphalt shingles. The idea behind such training seminars is to increase awareness and solicit sales of more roofing products. A manufacturer technician provides a sample installation on a 8×8 feet demo stand.

Bellow is and example of such “hand-on rubber roofing training”.

As you can see, the roofers just sit around the demo stand while the MFG Installation technician shows them what to do. The whole demonstration took about an hour and a half, and covered thing like installing flat roofing insulation (ISO), adhering rubber to the ISO board, flashing a sky-light / chimney penetration with un-cured flashing material, installing the membrane up the vertical wall, cleaning & priming seams and installing seam tape, installing drip edge and a tape to seal the drip edge fasteners, and installing termination bar. In the same 1.5 hours we’ve also learned “learned” how to correctly apply yellow glue – membrane adhesive, seam primer – seam & flashing glue and how to install these systems in the winter, while violating manufacturer’s installation specs.

Out of 25 or so roofing contractors present, there were about 15 or so questions particular to the installation details. 7 of them where asked by me! Bear in mind that I already knew how to install a rubber roof and attended the event to talk to my salesman, representatives of the metal roofing manufacturer and for free refreshments

In any case, each one of those 25 or so roofing contractors, willing to learn a new, and very complicated roofing system, asked an average of 0.3 questions about this systems.

Rubber roofs for residential customers: It was clear that my supplier and the roofing representatives were selling to Residential Roofing Contractors. Not once did they mention roof-top HVAC units, roof hatches, elevator shafts, gas/electrical pipes, roof drains, etc. They did however insisted that the rubber is a good choice for a low slope shed dormer (without mentioning the poor low slope roof ventilation and ice dam prevention associated with shed dormers). They also mentioned that rubber is a good choice for a flat roof decks and patios.

EPDM Rubber roofing and flat roof homes.

Homeowners with flat roof homes often find themselves in a situation where their roof starts to leak rather unexpectedly – i.e. only after a few years since the roof was installed. This for the most part happens to homes which have a rubber roof on them. While most flat roofs will only last 10-15 years, older systems such as Tar & Gravel, Bur and in some cases Modified bitumen roofs are usually installed by roofing contractors that are somewhat specialized in their scope of work – these are “the old-timers” or former union guys that decided to try their luck working for themselves, and they actually went through a special training and have years of experience. Problem is that roofing systems they install do not last long for many reasons outside the scope of this article.

Homes that have a rubber roof, begin to leak well before their minimal life expectancy is reached because in many cases they are roofed by your typical shingle roofing contractor that is so confident in his/her abilities, and a rubber roof is merely a roof with a low slope.

Why rubber roofs are so popular?

The truth is, rubber roofs (EPDM) are the most used flat roofing products in the US / Canadian commercial roofing market. Rubber roofs we first put in service over 40 years ago, and since gained popularity among roofing contractors and their customers. The reason for such success lyes in the condition of flat roofing market of that time and the available alternatives.

Back in 1960′s oil was still very cheap, it was more than a decade before the oil crisis of the 70′s and there wasn’t that much demand for oil. The oil refining process was far from being efficient and the industry was looking to get rid of many by-products of oil refining process.

At the same time flat roofing industry at that time was the same as at the turn of 19th century, and the most common product to use on a flat roof was either a BUR (built-up roofing, using multiple layers of tar paper, saturated in hot tar or hot asphalt) or Tar & Gravel roofing, which was essentially a BUR roof with gravel added for additional protection. Flat roofing technology has not changed for 100 years and contractors needed a new, easier to install and cleaner product, hence, the EPDM was born.

EPDM consists mainly of oil (carbo-hydrate) based by-products with some modifiers and stabilizers added to extend its service life. Rubber roofing was cheap to produce, easier to install that conventional (BUR) roofs, did not require any special equipment to put it down and the membrane could potentially last for decades, as it was UV stable and did not break down when exposed to the weather.

Because rubber roofing was cheap, quick to install, and offered a potentially long service life, and with lack of any opposition from better roofing products, it quickly became the king of flat roofing and the pioneer of the single-ply flat roofing market.

Useful resources:

DIY epdm rubber roof repair – Our original article on how to fix a rubber roof with EPDM rubber adhesive (no peel-n-stick tapes)

Rubber roof repair guide – A part 2 of our Do-it-yourself guide teaching you hot to fix EPDM rubber roofing systems with primer and seam tape.

In Part II we will take a look at newer, more advanced roofing technologies, and explore the advantages and disadvantages of each single-ply roofing technology commonly used today.

What is single-ply flat roofing?

There is a lot of confusion about single ply membrane roofing. Many people think that any ‘single ply’ is the answer to their flat roofing problems. This however is far from being the truth. In reality, single-ply roofing membranes have only one thing in common – that is they are single ply or just one layer of membrane that is a water proofing barrier. The similarity stops there.

Single ply membrane formulation, or the components a membrane is made of, is what makes the difference between different types of single-ply flat roofing membranes. Single ply roofing membranes come in various widths, ranging from 6 to over 18 feet. In theory, the wider the membrane is, the less overlapping seam you have, thus reducing the possibility of leaks. The reality is different however, and most commonly used membranes do not exceed 10 feet in width.

The most crucial aspect to the reliability and longevity of single ply roofs is the method of attaching overlapping seams together. That is where 99% of flat roof leaks occur. Therefore having permanently attached seams, is the most important factor in the longevity of a flat roof installation. We will discuss it in more details as we review different single ply roofing technologies.

Single-ply membrane installation methods:

Single ply membranes are installed either as a fully adhered or mechanically attached systems depending on each roof’s condition on other factors, as well as installer’s preferences in some cases. Underneath the membrane there s usually a separation barrier and/or some sort of insulation board. Most common insulation is ISO or EPS foam board. Both types have an R-value ranging from 4-R to 6-R per 1 inch of insulation thickness.

Mechanically attached installation uses heavy duty screws and barbed plates to hold membrane down tightly, and is not affected by possible ISO de-lamination. Membrane is attached using 12″ O.C. pattern with perimeter sheets attached 6″ O.C. This ensures even the hurricane-type wind will not tear off your roof. Mechanically attached installation method does not require use of heavy and expensive ballast, and is a preferred choice if your building is located in the high-wind area such as along the coast line or on a high hill.

Fully adhered single ply membranes are glued to the fiberglass sheet laminated to both side ISO insulation that in turn is attached to the roof deck. While quick and simple, fully adhered method has one serious disadvantage. If condensation forms underneath a roofing membrane, which often happens and my be cause by improper ventilation of the roof deck, it will ‘de-laminate’ ISO board and/or adhesive that is holding membrane in place. If membrane becomes loose, it is prone to a wind blow-off, which will leave your roof unprotected. Results of such blow-off will be catastrophic not only to your roof, but to the entire building. While this is rarely the case, it is still a possibility – a gamble you might not won’t to take.

A more common problems with fully-adhered single-ply flat roofing systems (Mostly EPDM rubber) are defects in glue/adhesive application that cause bubbles, badly glued seams and as a result, a very unpleasant view and more often then not, roof leaks. Image bellow demonstrated a defective Epdm rubber application.

Find out more information on why you should avoid installing EPDM rubber roofing on you home and how residential roofing contractors are trained to install rubber roofs.

Three most common single-ply roofing types:

Today, single ply roofing became the prime choice when it comes to flat roof replacement. More and more roofing contractors are switching from old roofing types like BUR, Asphalt, and Tar & Gravel roofs to single-ply membrane installation, which is easier, safer and faster. Single ply roofing installation does not use the torching, use in Modified Bitumen roofs installation, and therefore there is no fire hazard/possibility to bur down your home / business.

There are 3 most-used single ply membrane types present on the market today: PVC/CPA, EPDM rubber and TPO. While these abbreviations probably won’t tell you much, about these roof types, bellow we provide a brief summary of each of these technologies.

PVC (CPA)

• PVC – Polyvinyl Chloride – a thermoplastic membrane utilizing a reinforcement scrim between the two plies of equal thickness (IB roof only). Top ply contains Cool Roof pigments, UV stabilizers, and other components to extend the life of the membrane. Bottom ply contains PVC ingredients to provide consistent weld of top and bottom plies and fillers. Material Warranty Period: Up to 25 years Commercial / Lifetime Residential. PVC roof system life expectancy: 30+ years.
• Special Notes: For a complete overview of IB flat roofing products for residential, commercial and restaurant use, as well as installation method and roofing accessories refer to our IB Roof products page.

TPO

• TPO – Thermo Plastic Olefin – a thermoplastic membrane utilizing a reinforcement scrim between the two plies. 35/65 % thickness for top & bottom ply respectively. Top ply contains Cool Roof pigments, UV stabilizers, and other components to extend the life of the membrane. Bottom ply contains TPO ingredients to provide consistent weld of top and bottom plies and fillers. Note that the top ply is about half the thickness of the bottom ply. Yet the top ply is the one that make the roof long-lasting. IB PVC has a 50/50 or equal thickness of top/bottom ply.
• Material Warranty Period: Up to 20 years Commercial / NO Residential. TPO roof system life expectancy – 7 to 20* years. You should know that there is not a single TPO installation in existence in the USA, that was produced in North America and is older than about 15 years, . Therefore it is unknown how long a TPO system will perform without any leaks*.
• Special Notes: * TPO roof systems are under continuous development by numerous manufacturers, who constantly change the TPO formulation to achieve the lowest cost with acceptable performance. While it is understandable that business always look to save money and to reduce costs, these constant TPO development process is being conducted, often at the expense of the roof owner. A TPO roof from the same manufacturer will most likely NOT be the same as the one produced few years before or after. Also the quality of different batches of TPO membranes may be questionable, as some TPO producers release the product to the end user without getting the UL and similar approvals/certification, as the formulation changes too often.Refer to our comparison article of PVC vs. TPO to find out more of the TPO problems / short-comings.

EPDM Rubber

• EPDM Rubber – Ethylene Propylene Diene Monomer – a rubber-like black membrane, usually non-reinforced. Most common application method is a fully adhered (glued down) membrane with glued seams / flashings.
• Material Warranty Period: Up to 40 years Commercial / NO Residential. EPDM roof system life expectancy – 10 to 15 years. Although the material warranty goes up to 40 years for a 90-mil Epdm from some manufacturers, it does not cover the seams. Failing seams are the main cause of EPDM roof leaks followed by ponding water, for which EPDM has no warranty either.
• Special Notes: EPDM is the least expensive single ply roofing type and requires no special equipment to install it (unlike PVC and TPO which require hot-air welding equipment) and thus is the first choice for roofing contractors entering the flat roofing market and asphalt shingle roofers that ‘install rubber here and there’. Although many commercial roofing companies also use EPDM, they usually do not perform Residential installations so many times a home owner deals with a Part-Time flat roofing company.

Please note that there are many manufacturers of all three type of roofing and each has their own formulation / manufacturing process / warranty conditions and periods, etc. Therefore we only provide a generals summary for each of those roof types. Also, since our specialty is installation of IB roofs, when we use the term PVC or CPA we refer to IB PVC Roof (CPA is the way IB Roof Systems refers to its PVC product. IB membranes are generally ‘compatible’ with other PVC products).

Common single-ply flat roofing choices: CPA/PVC membrane – IB Roof

CPA/PVC single play flat roofing membrane made by IB Roof Systems is by far, the best choice for any type of flat roof. Main advantage of IB’s CPA/PVC membrane is that the seams are Hot Air welded creating a physical bond between the sheets, that is stronger than the membrane itself. Such seam is a permanent seal, ensuring that there will be no leaks even if you have puddles of ponding water on your roof (which by the way is covered under IB’s warranty, unlike other types of flat roofing membranes that only cover the defects in material). IB’s CPA/PVC white membrane is the true energy efficient Cool Roof, this will not only give you years of worry-free performance, but will actually save you money in reduced energy costs. IB also offers a variety of colors, many of which will also qualify to carry a Cool Roof label. But the main factor speaking in favor of IB’s CPA/PVC membranes, is that they historically proven to last over 25 years without a single leak!

Learn more about IB’s outstanding single ply flat roofing membrane, its advantages and many choices for Residential, Commercial and Restaurant use.

Purpose of a flat roof or any roof for that matter, is to keep your home or building safe and dry. The roof MUST protect your investment from the elements such as rain, snow, and even sun’s heat. However, many flat roofing technologies on the market today, have some major, inherited drawbacks that take origins in its design. In fact, most flat roofs fail to serve its main purpose just a few years after they are installed.

You are presented with so many choices for a flat roof and every roofing contractor will tell you their product is the best. But which one do you choose and how do you know that you are getting the best deal? Here we have summarized the most common and ‘popular’ flat roofing choices. You be the judge and decide which is best for you.

Benefits of flat roof construction:

There is a common misconception among many home-improvement contractors and residential builders / architects that flat roofs = problems. The truth is such that flat roofs are very convenient, easier to build, and cost less than pitched / sloped roofs. In some cases flat roof is the only way to go, when you have a large size building. Building a reliable pitched roof in those cases will require extra engineering to accommodate for additional structural weight.

Flat roofs are also convenient for installing large HVAC equipment that otherwise would have to be installed on the ground. You can also use flat roof as a roof-top deck, patio or penthouse. Green roofs are also gaining popularity with environmentally conscious companies and organizations.

When you compare all the construction costs and environmental benefits, flat roofs by far surpass any sloped roof, for which, the roof products of choice are ail-based asphalt shingles. These asphalt shingle end up in our land-fills every 12-15 years, and yet more and more of them are produced.

Limitations and Disadvantages of flat roofing:

Flat roofs also have their portion of disadvantages. Main one is the fact that there is no slope and all the water/snow sits on the roof. While water can be taken care of with proper drainage, snow will sit on the roof until it melts. This requires the engineers / architects to implement building components with higher structural load. Another disadvantage that haunted flat roof installations for over a century is ponding water. Until the invention of single ply membranes such as IB roof, there was no effective and economical way to eliminate the leaks caused by ponding water. That had to be taken car of in the initial design/construction stage. Creating a slight pitch and multiple drains was required and still, ponding water caused over 75% of all flat roof leaks.

Now the ponding water problem is solved by either implementing a slight pitch to the roof – such as in ‘space metal buildings”, using tapered insulation to direct water flow toward drains and with the creation of IB PVC / CPA roofing with hot-air welded seams, ponding water is no longer a problem in small quantities. It is still necessary to have adequate drainage system, since a lot of ponding water can cause structural damages to your house or building.

Types of flat roof: Modern and Outdated roofing technologies.

Outdated (Multiple-Ply Roofs) – some are over 100 years old:

• Build-Up Roof (BUR)
• Tar & Gravel
• Bitumen (Modified Bitumen)
• Rolled Asphalt (usually a “single-ply” install, sometimes uses tar-paper as base ply)

Modern (Single-Ply Membranes)- created within last 30 years:

• IB Roof (PVC roofing) – IB PVC roofing membrane is one of the best low-slope and completely flat roofing products available, and that is precisely the reason why we only install IB roofs. With over 30 years of spotless reputation and leaks-free performance in many different climates – from Alaska’s frigid north-lands to Hawaii’s tropical paradise, IB roofs are protecting the buildings and everything inside, without a single material failure since 1978.
  
  IB roofs still feature the same chemical formula as its original design, and with hot-air welded seams, will maintain complete water-tightness over your roof.
• Epdm Rubber Roof – a widely used flat roofing material, mainly popular among contractors because of its low price and no special equipment needed to install the rubber roof. Still, rubber roofs are very prone to leaks, as the seams are glued together, and adhesive tends to break down within 5-7 years. Also in residential roofing market (and not so much in commercial) there are too many contractors who will install rubber roofing products without proper knowledge and training. As a result, we often go to rubber roof repair service calls to fix the workmanship problems, often on fairly new roofs.
• TPO Roofing – a single ply thermoplastic roofing membrane similar to PVC roofs from a first glance. But as you start digging, you’ll find numerous problems with TPO roofs, mainly as a result of manufacturers skipping on adding important ingredients into formulation if TPO membrane, and as a result, quietly scrapping as many as three major generations of the product.
• SFR – Sprayed Foam Roofing (not a single-ply)

Part I: Inferior and outdated flat roofing technologies

These are very common on older building, although many newer buildings also have these systems installed. They are rarely installed on any commercial building today. However they are continued to be produced, and many roofers still install them on residential and small commercial roofs. Particularly due to their low cost of material and roofers’ lack of experience with BETTER solutions. It is sad that there are some decent roofers offering such an inferior product to their customers. I often hear something in the lines of: “I’ve been doing ‘torch-down’ for 20 years, and it is the best” – very sad – so we will briefly describe them, not going into details.

BUR / Tar & Gravel / Torch-down: Multiple-ply roof where each ‘tar-soaked’ ply is applied with a torch (yes, open flame on your roof!), or hot mopped (preheated tar transported to the roof and applied with a mop). Gravel goes on top of this ‘sandwich’ mainly as a protection layer from foot-traffic and sun’s devastating ultraviolet rays. There are many derivations from the above procedure, but they are all within a close range of similarity.

Modified Bitumen: It is also applied with a torch in a similar manner described above. It is however a different material than tar. Modified bitumen has rubber and elastomers added into the formula, so it is stronger and more flexible.

Rolled Asphalt: Similar to asphalt shingles – tar paper saturate in asphalt, with crushed stones glued on top of it. Rolls are installed in overlapping pattern, with cold-mop application and nails to attach it to the roof deck. Overlapping seams are sealed with tar.

Problems associated with flat roofs:

The nature of flat roofs’ problems is just that they are flat. Water does not run off the roof. Proper drainage must be in place to get rid of water accumulating on a roof. Usually older roofs are not leveled, so water puddles will appear here and there after every rain, and just sit there until it dries out. This is called standing or ponding water. Most roofing systems were not designed for ponding water. In fact, most manufacturers of the roofing systems on the market today, will void out the warranty if there is ponding water on the roof (we will get to this issue later). Other major problems for flat roofs, are penetrations such as skylights, vent or exhaust pipes, chimneys, roof hatches, drains, etc. However the biggest problem of flat roofs is the seams. Seams are the most common place for a leak.

Seams:

Seams exist on every flat roof (except tiny ’6×10 porch-type’ roofs, which can be covered with a single sheet of roofing membrane), and are usually put together with some sort of adhesive. After few years the adhesive breaks due to severe weather changes (here in New England, temperature can change 25 degrees or more, in a matter of one day). Another major factor affecting seams’ adhesive is condensation, which always occurs underneath the roof covering. Condensation expands both in the winter and summer. Most dramatic expansion of condensation happens in the winter time when water freezes, expands and breaks the seam. Same happens to our roads. Think of all the potholes you drive over. Those too were caused by water freezing. In the summer water heats up and also expands. When you see bubbles on the roof surface, it is the water vapor lifting the membrane. Third major factor is actually quality of workmanship and the adhesive itself. For different roofing systems the process is different, but most of them share the same shortcoming – the need of using adhesives, be it glue, hot tar, liquid resin, etc. Adhesives are also required to flash any roof penetrations listed above, but here the workmanship is actually more of a factor than the adhesive.

Conclusion – let’s get real.

It is a shame that in the 21st century we are still using 19th century technology. Even more so, because nearly 50% of roofers in the on-line construction forums will advise you to choose a clearly inferior roof. These heavy and dirty roofs, heat up to 170 degrees and make your AC run like crazy in the summer. These very roofs start leaking prematurely and are impossible to fix. Why would some one acting in good faith actually recommend these? Answer is obvious – they don’t know any better. Fortunately there is ONE modern, technologically advanced flat roofing solution available on the market today – IB Roof. In fact this solution had been around for a few decades now, and has a proved track record of 30 years of leak-free service!

Read more: Part II – Single-Ply Roofing Membranes – CPA / PVC / TPO / EPDM / SPF