IB flat roofing

Flat Roofing Materials – EPDM rubber, BUR, Tar & Gravel & Modified Bitumen

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Flat Roofing systems: The 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 the sun’s heat.

However, many flat roofing technologies on the market today have some major, inherent drawbacks that have origins in their design. In fact, most flat roofs fail to serve their 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 can 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 that flat roofs are very convenient, easier to build, and cost less than pitched / sloped roofs. In some cases, a flat roof is the only way to go, for example, 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.

IB roof replaces two sections of this textile factory roof located in Central Falls, RI. These two sections had the most leaks, which were damaging expensive machinery.

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.

Average Flat Roof Costs in US Average Flat Roof Costs in US
Rubber Roof
PVC Roof
TPO Roof

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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 oil-based asphalt shingles. These asphalt shingles end up in our landfills every 12-15 years, and yet more and more of them are produced.

Limitations and Disadvantages of flat roofing:

Flat roofs also have a number of disadvantages. The 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 a 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 an IB roof, there was no effective and economical way to eliminate the leaks caused by ponding water. That had to be taken care 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.

  • Average Flat Roof Costs in US Average Flat Roof Costs in US
    Rubber Roof
    PVC Roof
    IB PVC
    TPO Roof

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  • 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 the 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 problems caused by poor workmanship, 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 of the 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 buildings, although many newer buildings also have these systems installed. They are rarely installed on any commercial building today. However, they continue to be produced, and many roofers still install them on residential and small commercial roofs. This is 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 along 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, without getting 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 deviations 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 is saturated in asphalt, with crushed stones glued on top of it. Rolls are installed in an overlapping pattern, with cold-mop application and nails to attach it to the roof deck. Overlapping seams are sealed with tar.

Rolled asphalt flat Roof in Providence, RI is failing prematurely - seams coming apart, seam adhesive fails, nails backing out, and as a result: roof leaks inside the house.

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 with flat roofs is the seams, because they are the most common areas where leaks occur.

Average Flat Roof Costs in US Average Flat Roof Costs in US
Rubber Roof
PVC Roof
TPO Roof

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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 a 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. The most dramatic expansion of condensation happens in the winter time when water freezes, expands and breaks the seam. The 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. The 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 for 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? The 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 has 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 – PVC, TPO & EPDM Rubber Roofing.

Roofing Price Calculator: Estimate the Cost of Flat Roof Replacement

This Free Roofing Price Calculator is designed to give you a rough idea of how much it is going to cost to install a new flat roof, or to replace an existing one. It will also calculate approximate energy savings derived from installing white* (most energy efficient) IB membrane vs. black rubber (EPDM) or Tar & Gravel/BUR roof.

Quick Navigation:

  • How roofing cost is calculated – Understanding the roofing price structure and the specifics of our calculator.
  • Learn how to use our roofing calculator – If you have questions on how to use our calculator, or need to know which info about your roof is required, read this quick user guide.
  • Roofing material price updates – Because roofing materials as many other products are dependant on price of oil &amp and other factors, we’ll update you on any major change in roof material costs.

Calculate you roofing cost now!

Roof dimensions: x

# ft. (numbers only)

Insulation thickness:
Relative Roof Difficulty:
Tear off existing roof:

Approximate Roofing project price (press ‘Calculate Roof Price’ button to get results) – Sometimes you will have to wait a few seconds to get the price results:

Get an IB single-ply roofing membrane installed on your roof – fill out our roofing estimate request and get a free price quote customized to your roof.

Please remember: these prices indicate approximate cost to install a 50-mil white IB Roof, 80-mil IB or the residential IB Traditions Membrane over an average size home (in a 1000 sq. ft. range). Above roofing prices DO NOT indicate installation costs of IB DeckShield or flat roof deck/patio with PT wood installation.

Please note that if you are still receiving last year’s prices, there is a good chance that you will receive a sub-par service, and/or your roofing contractor will use every chance to reduce their costs ( cut corners whenever possible ). No roofing contractor is immune from rising material prices unless they hold a huge inventory (nearly impossible). Therefore, if you get a “great deal”, you may not get a great roof.

How to interpret the instant price quote:

We want you to know that your actual installation cost may vary based on the specifics of your roof and your roof difficulty, and the roofing contractor you use – refer to our roofing price guide for more insight on how roofing contractors come up with their prices. Also, you should know that the price for Tar and Epdm roof material greatly depends on the price of OIL, which was trading at its all time high of $147 per barrel in July of 2008. Although oil prices have fallen dramatically since then, the material costs remained the same and in some cases (for asphalt-bases products such as shingles, rolled roofing, built-up roofs, modified bitumen and EPDM rubber) they actually continue to increase – the last major price increase occurred in March 2009 with all the major roofing manufacturers. Since we DO NOT install Epdm or Tar roofs, we provide you with our estimated cost, based on our experience. Epdm and Tar roof prices also vary from one roofing company to another.

Dear visitors, please be aware that results of our calculator do not always reflect the price quote you are going to receive from us. Our calculator is designed to provide approximate pricing to install a 50-mil white IB roofing membrane on an average size home (1000-2000 sq. ft.). If your roof is small (about 300-400 sq. ft.), then your cost/sq. ft will likely be higher than results from this calculator. This is due to the fact that our set-up costs remain the same, while the amount of work is smaller.

Like-wise, if your roof is large, your cost per sq. foot may be lower, depending on various variables. There is no exact formula on how the price is calculated, as there are too many factors affecting the price of each particular roof, and including them would make our roofing calculator too complicated to use.

Also bear in mind that Specialty Membranes such as IB Traditions for Residential low-slope roofing or 80-mil IB roof will be slightly more expensive compared to a standard 50 mil roof.

IB DeckShield or 80-mil membrane assembly with Pressure Treated wood on top for walk-on flat roof decks will be considerably more per sq. ft., compared to results from our calculator. Please refer to our flat roof decks section of our website for explanation of our walkable flat roof assembly for both Deck-Shield and 80-mil with PT or composition deck.

How to use this roof price calculator

Plug in your roof dimensions into the calculator. Make sure you account for any overhangs / soffits, as that may add significant area to you total roof size. If your roof has an odd shape ( ‘L’ shape or similar ) you can divide your roof into virtual ‘rectangular blocks’ and add up all your measurements to get the total square footage. Plug in that number and multiply it by 1. For example: if your roof is 2300 sq. ft., type 2300 x 1 into ‘roof dimensions’ section of calculator.

Use appropriate ‘roof difficulty’ setting to get a more accurate roof price estimation. Although your roof may look simple, roof penetrations like sky-lights, chimneys specialty vents, AC units, etc. take a long time to flash correctly, therefore adding a significant amount to the total price tag of the roof.

Choose the desired insulation thickness. Insulation makes up a significant part of total material cost, and in some cases may cost more than the roofing membrane itself. Having good insulating value may seem expensive at first, but it will greatly reduce your energy costs, eventually paying for itself. However, if you already have some insulation, adding more will not have a dramatic effect compared to having no insulation at all.

When comparing prices of an IB roof and the cheaper alternatives like Epdm rubber, bear in mind that total roofing cost concept. While IB has a higher initial cost of installation, the difference in price will be more than offset by savings in future roof repairs, energy savings, and virtually no maintenance required for the IB flat roof.

When looking at the numbers produced by this calculator, bear in mind that each roof is different, and your actual cost will depend on your roof’s difficulty level, as well as a number of other factors, such as ease of access, IB membrane thickness and the type you choose, insulation thickness, etc.

Relative Roof Difficulty: Please Choose according to how many through-roof penetrations/HVAC units/Skylights/Vent or
Hot-stack pipes, etc., are on the roof, as this will make a significant price difference. The more penetrations, the more precision
work will have to be performed.

Roofing Material Price Update – June 20, 2008

As you know the price of oil increased more than 80% in the last 6 months, which in effect increased the transportation and food costs. However, unless you are a roofer, or involved with the construction industry, you may not know that roofing material prices have also risen more than 30%. This is especially true for roofing materials such as Rubber, Asphalt and Modified Bitumen roofing, as they all use oil-byproducts as one of the base components. Since roofing contractors cannot absorb a 30% increase in material costs, as well as other cost increases such as gasoline price hike of more than 40% since November of 2007, the price of roofing installation is also on the rise. Expect a 10-20% increase in the roof price for the above mentioned roofing materials (EPDM, Mod. Bit. and Built-Up Roofing).

IB Roof Material Price Update – Sept. 30, 2008

As with most other construction materials, IB roofs are not immune to rising manufacturing, materials and transportation costs. We had two material price increases – one on July 1st and a second one in the beginning of September. In total, materials prices went up 18% for us, as well as increasing transportation costs.

Fortunately, we purchased a stock of 50-mil white IB membrane before the July 1st increase in prices, so for a limited time we can still offer June installation prices. This is of-course until the stock runs out. Don’t wait too long.

We have modified our roofing price calculator to reflect the recent material cost hikes by a reasonable 10%. These installation prices assume that a roof is installed by a reputable roofing company that is fully insured and licensed, and specializes in flat roofing. If you get a “great” deal from someone, don’t be surprised if your seemingly inexpensive roof leaks soon after it is installed, and your roofing contractor is nowhere to be found. Refer to our flat roof repair guide for some insight and ideas on what to do if your roof leaks and what your options and costs are.

* IB White Membrane has the highest solar reflectance rate of almost 90%. Energy savings refer to the avoided cost of
electricity to operate the AC in the summer. Our calculator does not consider the R-value of insulation as a savings factor.
However, the thicker the insulation, the more savings you’ll realize all year round.

** Savings are calculated assuming the electricity rates in Metro Boston area from N-Star, effective April 1, 2007.
The going rate then was $0.1875 / kWh, for the consumption of 1000 kWh per month. Electricity rates found in the following
report from Hydro Quebec:
Hydro Quebec Electricity Rates
report – 2007
Your actual rate may vary. To calculate your rate per kWh, look at your last 12 electric bills. Add all 12
statement balances (exclude any previous balances, late fees or other misc. charges not related to your energy use), and divide by the total number of kWh consumed.