Our Mid Century Modern Flat Roof Restoration
Beginning in May of 2017, we began to restore our flat roof, interior beams and clerestory (high) windows. We wanted to do this for a number of reasons: Restore the look of the house from the outside to make it fit back in with the rest of the neighborhood (5 other homes designed by the architect, Norman F. Carver Jr. all have flat roofs), to improve the interior light quality and to restore the architectural details hidden by drop ceilings.
The project was a big one, but I wanted to be as involved as possible every step of the way. We had some expert advice and support from roofing professionals, but ultimately I oversaw the roof restoration from start to finish. Most of the work was done by me and two young men who had plenty of roofing experience. While it was a project that took several months in total, I believe that we now have an excellent roof - and it was a fraction of the cost that a full professional roofing team would have been.
In May, I began by removing the drywall and 2x4s added as nailers for the drop ceilings covering the beams in the study, screened porch and master bedroom. The living room had a latticework of 1x2s and 2x6s covered by a kind of tongue and groove ceiling panel. It was great to see the beams were in good condition and that the original ceiling/roof deck boards were also intact and not needing to be replaced. These findings allowed us to proceed with the main goal of removing the pitched roof and restoring it to flat. In a way, the 'lazy' methods used to cover up the beams made it relatively straightforward to reverse. Pulling several hundred framing nails by hand was not fun though!
The pitched roof consisted of premade trusses on nailing blocks attached directly through the existing flat roof. OSB decking and asphalt shingles were nailed onto the trusses. The chimney had also been extended 8' to clear the new pitches. All of this material was removed. We also removed 2 layers of old / original flat roofing material (one rubber and one tar and gravel) and altogether with the pitched roof material we filled 3x 30 yd dumpsters!
Once the old roofs had been removed we tackled other problems such as
- Rebuilding trellises which had been cut off for the pitched roof installation
- Rebuilding the roof overhangs on the ends of the high section above the clerestory windows
- Replacing broken clerestory windows
- Devising a way to raise the curb at the bottom of the clerestory windows as this is apparently a major source of leaks in the neighboring houses
-Removing posts that had been added to take the weight of the trusses on the eaves.
Once these issues had been taken care of, we began installing tapered ISO insulation board with long screws and plates to give the roof a slight pitch of 1/4" per foot. This is imperceptible from the road so the flat roof look is maintained. As the high roof section is 36' long we added ISO board to control water runoff to the ends (not edges), meaning there is a peak in the center of about 5". We added fascia boards later to disguise this pitch.
The TPO roofing material was easy enough to glue down directly onto the ISO board but the long pieces need three people to roll in well coordinated fashion. We minimized the number of seams and heat welded them for water-tightness. Edges were trimmed and nailed over edges on the fascia boards. We then nailed on 2 inch drip edges and sealed the transition with TPO PS coverstrip, creating a neat edge. We used Mulehide TPO products from ABC Supply. We chose these based on availability, cost and an excellent series of installation videos and diagrams they provide on their website.
Unusually heavy rains led to leaks during the tear-off phase and once we'd installed the roof - this helped us identify problem areas (mostly around the end clerestory windows) before the winter weather set in and we were all sealed up and watertight by September.
All in all, it was an exciting, challenging and rewarding project! We love the results and are glad that we did it ourselves before winter and saved a lot of money by doing so.
(Aerial photography by Kalamazoo Aerial Media. They do great work!)