Steep Roof and Metal Shingles: We were selected as the general contractor for the St. John Lutheran Church 2009 Re-roof Project. This roof was a very steep 18/12 & 24/12 pitch. The project required proper, licensed removal of the existing asbestos shingles and the single layer of buffalo board underneath the waterproof felts. We installed a new roof consisting of two layers of 3 inch foam insulation with an OSB nailer layer on top. Roof felts and metal shingles were installed over the nailer.
It was originally an uninsulated "hot roof" construction where the underside of the roof boards were also the visible ceiling in the church, so the screws to attach the insulation and nailer had to be long enough for sufficient hold, but not too long to penetrate through the roof deck. We found the specified screws had insufficient hold so we located a better screw, which the project architect and warranting manufacturer approved.
We had concerns that the support blocking specified was insufficient to hold the weight of the roof, given how steep the roof was. The design drawings showed a generic blocking detail for a much lower pitched roof. After further engineering the architect agreed with our concern, accepted our proposed stronger support blocking details, and increased the screw count for each sheet of insulation.
Some of the work was done from tall boom lifts, mainly to lift the material up or down. But for greater efficiency the demolition and installation was done mostly while standing on the roof, using safety harnesses with climbing hardware to easily adjust the rope length for mobility and to assist in climbing the roof.
Going from a completely uninsulated roof to a code compliant insulated roof should bring a quick return on investment due to reduced heating cost for the church.
Shake Shingle Roof: The first project was simple enough, tear off and reshingle a rotted wood shake roof, but it was a very large roof, seven thousand square feet, and the owner wanted very thick shakes, not the standard, usual thickness. And he wanted to do everything possible to extend their life; to keep them from rotting and to retard the growth of moss. Through our local supplier, Alexander Lumber, we located thick wood shakes from a supplier in the Pacific northwest. We also learned of a breather fabric that we installed between the waterproofing felts and the shakes. This fabric allowed for better drainage and air circulation under the shakes so they will dry out quicker and be much less likely to rot.
To prevent moss growth we looked at two products. One was a spray on organic solution. It was expensive and had to be sprayed on every few years and required the roof to be thoroughly cleaned before application, adding to the overall lifetime cost. The second solution we looked at and installed was Z-Stop Zinc Strip. Z-Stop can be installed on composition, shingle, shake or tile roofs. It is installed at the roof peaks, under the ridge cap, beneath chimney gables, skylights, etc. It won't remove existing moss but inhibits the growth of moss on new or newly cleaned roofs.
Roof board tear-off: Our final unique roof project for the season was for an older, large lakefront home with a poorly insulated roof. The roof consisted of 2x6 joists with the drywall ceiling attached directly to the bottom of the joists and the plywood roof boards attached to the top of the joists, with six inches of insulation between. This construction was far from adequate by today's code standards and energy costs, and left virtually no room for air circulation to vent the roof. Then, while searching for a leak that needed repaired, we cut in to the roof deck and discovered that the insulation had sagged, leaving large spaces with no insulation at all.
The owner decided to have the roof re-insulated. Rather than tearing in to the interior drywall ceiling, after tearing off the roofing material we tore off all the roof boards and removed the fiberglass insulation batts. We cut six inch thick sheets of foam insulation to fit between the joist. We foam caulked around all the edges to seal the cracks then added furring to make the roof thicker and allow for correct venting. Slightly taller fascia boards and new very heavy duty shingles completed the repair.
As with all our jobs, with these three roof projects we were able discover and research the problem and adapt our solulution to provide the best finished construction for our customer.
