Replacing an old rubber roof with IB PVC roofing membrane in Lowell, MA.
In the beginning of Dec. 09 we installed a new IB PVC roof in Lowell, MA. This roof replaced an old EPDM rubber roof which was installed by a hack roofing contractor about two years ago, and was failing miserably, due to two factors: poor roofing system design on the part of EPDM roofing, and horrible installation by the roofing contractor. I suspect that this contractor had almost zero knowledge about flat roofing and rubber installation. Before I go into the IB roof installation, I want to talk a bit about the two factors mentioned above that contributed to the roof failure.
The roof actually consisted of two roof sections not connected to each other. One smaller roof in the front of this historic home was about 100 sq. ft. in total, but its shape made using a rubber roof not feasible due to limitations / flaws of rubber roof system design. Another roof section was just over 300 sq. ft. and covered an enclosed porch in the rear of the house. This section had a low slope to it (about 2 in 12 pitch) and a hip roof design. The failure of both front and rear roof sections was the result of bad installation by the roofing contractor and EPDM rubber roof shrinkage, as well as seam adhesive failure.
Rubber roof failure due to EPDM flaws and limitations and faulty installation by a roofing contractor:
When EPDM rubber roofing membrane is installed on a roof connected to a wall of a building, the membrane must be laid down with a flap going up the wall – in essence, the wall flashing and the roof covering must be done with one piece of material to eliminate leaks in the the roof to wall connection. Therefore, the field sheet of roofing membrane is only held down by glue (which happens to break down after 5-7 years). While in some cases this work out fine, very often the rubber shrinks and pulls away from the wall-to-roof connection point. This results in either the detachment of wall flashing, membrane pulling away from the corner of roof to wall connection, or in some rare cases, when the wall flashing is securely attached to the wall, the shrinking rubber roof may pull the wall with it – for example it can pull a brick parapet wall.
IB PVC roof is installed differently. All membrane is terminated at the roof to wall connection with heavy duty fasteners (screws or masonry anchors) and barbed plates, to hold the membrane down. A separate wall flashing is installed up the wall and 5-6″ away from the wall, covering the screws and plates, and is welded to the roof, making the wall flashing watertight. The wall flashing is attached to the wall using either an aluminum termination bar, or nailed to the wall in cases when it will later be covered by siding.
At the edges of the roof, a PVC coated drip edge is installed into pressure-treated (PT) wood nailer, using roofing screws to securely attach it to the roof deck, and to prevent wind uplift. Then the IB PVC roofing membrane is welded to the drip edge. In case of a rubber roof, the drip-edge is nailed down with smooth-shank roofing nails. This makes pull-out very easy – strong wind can pull the rubber roof off, or as in this case, the rubber shrinkage pulled the whole assembly away from the roof edge. In rare cases, a rubber roofing contractor will use the roofing screws to attache the drip edge. Most of the time, a roofing contractor will install drip edge right over soft insulation, with 2 or 3′ roofing nails. You can easily pull off this drip edge by hand, even if its nailed 6″ o.c., as we did on this roof.
IB flat roof installation:
Roof Insulation: The homeowners who just purchased their Lowell, MA home recently, wanted to improve insulation over the back porch, while the front roof was already insulated between the rafters. We used 24–r value, 4-inch Poly ISO insulation board on the back roof and 1/2 inch fan-fold insulation in the front. Because of the design of the rear roof section and the short distance between the two rear windows and the roof, we needed to use tapered insulation to actually reduce the thickness of ISO board from 4″ to 2″ at roof to wall connection. This allowed us to properly flash the roof to the wall, though gradually reducing insulating value from 24-r down to 12-r at the wall.
Roof tear-off: To keep installation costs and land-fill waste down, while installing the roof in accordance with MA building code (which allows no more than two layers of roofing material, unless approved by structural engineer and building inspector), we removed one layer of rubber roof and the fiber board, leaving the old tin roof on the front roof, and rolled asphalt on the rear roof in place.
Day one – installation of smaller front roof.
The first thing we had to do on the first day was to get a roofing permit from the Lowell building department. Since homeowners just recently bought their house, the building department did not catch up with the assessor’s office on the current owners of the property (and why would they do any extra work if they don’t get paid for it?),so it took us some time to square things away. After we got the building permit, it was placed in the appropriate spot – front window of the house. Now it was time to get to work.
The roof was installed between to snow-storms – one right after Thanksgiving and another one just a few days later. On the first day we had to shovel all the snow off the front and rear roof, and then remove the rubber membrane off the front roof. We decided to leave the rubber on the rear roof until we actually had time to get to it, since it was supposed to snow and rain the day after.
Once the rubber roof was removed, we installed the perimeter wood nailer and laid down the insulation. We then installed the drip edge and sheets of IP PVC roofing membrane, which were pre-cut on the ground, to simplify installation on this already tight roof. An IB membrane was welded to the PVC coated drip edge and mechanically fastened down to the roof deck with heavy duty screws and plate in-filed and along the roof to wall connection.
Roof to wall flashing: A separate roof to wall flashing was installed, and welded to the roof, and nailed to the wall and attached with aluminum termination bar along the exposed wall. Inside and outside corners were flashed with IB non-reinforced corner flashing material, which was welded to the roofing membrane.
At the end, an IB 5″ two-way air-vent was installed to remove the condensation between the roofing membrane and insulation. The installation of roof to wall flashing took as long as the rest of roof installation. Since the roof to wall flashing was the main part of rubber roof failure and the most difficult part of this installation, we had to spend extra time, making sure this one will last a lifetime.
Day two – installation of the rear roof.
Rubber roof tear-off, insulation and IB membrane installation all had to done in one day, so the roof would be watertight after we left the job site for the night. We left all the finish and detail work for the last day – our main goal was to have the roof covered at the end of the work day. Fortunately for us, the rubber roof came off very easily, as the glue barely held it, and the drip edge was popping of like popcorn. We also removed the old fiber-board, to maximize the clearance between the window sills and the roof.
Once the old rubber roof was removed, we started laying out our 4 inch high wood nailer along the roof’s perimeter. We used double 2×6 PT boards with 1/2 inch strips of PT plywood in the middle – this gave us almost 4″ total thickness, to match the thickness of ISO insulation. When the wood nailer was installed, we laid down the double 2″ insulation boards along the outer perimeter of the roof. At this point we had to start the tapered insulation. We first laid down 1″ ISO board and then double sheets of 1/4″ per foot tapered ISO, to bring the total insulation thickness from 4″ to 2″ over 4 feet distance.
Once all insulation was laid out, and fastened down according to FM Global insulation fastening standards (8 fasteners per 4×8 sheet of insulation), we installed the pre-cut rolls of IB membrane, which was fastened down 12″ O.C.
First we installed a perimeter half-sheet roll, and then a full width roll, butting it against the wall. Now it was time for the roof to wall flashing and termination. Our roof to wall flashing was made out of 3 pieces of 2 feet wide IB membrane to have appropriate up-the-wall flashing. After the roof to wall flashing was installed and all seams welded, we installed two outside corner flashings. Now the roof was watertight, it was already dark, and time to go home.
Day three – installation of drip-edge, cover tape and cedar clapboard siding.
On the last day we installed the special order 5″ wide face drip edge, which we installed over the IB membrane, and welded down a 6″ IB cover tape to the drip edge and the roof. All joints between the 10 foot sections of the drip-edge sealed according to IB installation spec to prevent roof damage from expansion and contraction of the metal. A 2″ foil-tape was placed over the joint and a 5″ IB flashing material was welded on top. We also replaced the old cedar clapboard siding, which was rotted and fell apart after we removed it to install the roof to wall flashing. Although it does not seem like a lot of work, it actually took us an entire day to complete. As the last finishing touch, we installed a 5″ two-way membrane vent in the center of the roof.
Information for homeowners regarding flat roofs:
Words of caution: we strongly recommend home and building owners to avoid installing an EPDM rubber roofing membrane. Besides the faulty design of this roof, there are too many shady contractors, with little or no experience, who can buy rubber roofing material at almost any roofing supply warehouse. You may be attracted to a seemingly low price of EPDM rubber roofs, but be aware that a low price comes with VERY low quality of workmanship, and to compensate for low prices, these contractors will use cheap rubber glue and accessories.
When you choose to go with a quality flat roofing product like IB Flat Roofs and a professional contractor, you will not be paying twice for a new flat roof and dealing with roof leaks and finding your rubber roof installer to fix the leaks, like the one bellow:
Leaking rubber roof in Quincy, MA, installed directly over asphalt shingles:
Look at the picture above – it is a 1 year old EPDM rubber roof that was installed by a shady “rubber roofing specialist” contractor, who disappeared, and does not return the home owner’s phone calls. They glued the rubber membrane straight to the asphalt shingles roof, which you can see “telegraphing through the rubber. This roof has leaking ever since it was installed. Read more information about rubber roof materials, roofing contractors and their training in installation of rubber roofs (or lack of such training) in our rubber roofing guide for flat roof owners.
If you have a leaking rubber roof in the Metro Boston area of Massachusetts, and can’t afford to replace it now with an IB PVC roof, we can repair you EPDM rubber roof with high quality EPDM peel-and-stick flashing accessories - MA rubber roofing repair services start at $350 and include 2 hours of repair work, and necessary materials to complete the repair. Fill out the rubber roof repair request form to schedule a a professional roof mechanic to come and fix your commercial or residential EPDM rubber roof.
Getting IB roof installed on you flat roof in Massachusetts:
If you have a flat roof in Lowell, MA, or another city in Massachusetts, we can install and IB PVC flat roofing membrane on the roof of your home or business – fill out our roofing estimate and price quote request form and don’t forget to use our roofing price calculator to estimate your roof replacement costs, and compare prices to EPDM rubber, Tar and Gravel roofing.
Written by Leo - roofer with a vision. Follow Leo on Google+