At some point during your roof replacement planning stage, your roofing contractor might inform you that your roof will need to be re-sheeted. Here’s a look at what roof re-sheeting is and why your roof may need it.
The roofing substrate, also known as decking, is the roofing layer to where the waterproofing barrier and outer roofing are attached. Homeowners today would be familiar with substrate made of plywood or oriented strand board (OSB). However, if your home was built before 1970, chances are it has a different type of substrate.
Shiplap substrate is built using fir wood planks and was the standard material used as substrate from the 1940s to 1970. The fir wood planks are fastened to the trusses and then covered by the waterproofing barrier (“felts”), followed by asphalt shingles. However, half-inch thick plywood has been found to be the superior substrate material and, by 1970, had replaced shiplap as the standard substrate material.
Roof repair and installation contractors like us will recommend re-sheeting if the existing roof still has shiplap substrate. This means the roof is around 50 years old. The resin in the planks would already have dissipated, making it unsuitable for today’s installation processes. The fir planks may also have gaps between them from years of expansion and contraction due to temperature changes.
Re-sheeting involves removing the old shiplap substrate and replacing it with plywood or OSB. Before that can be done, we need to make sure that the roofing structure itself is in sound condition. This is an important step if you are planning on switching to a heavier type of roofing system, such as slate or tile. If the timbers that make up the roof structure are in the same state as the shiplap substrate, then the roof will have to be rebuilt completely.
Why Re-Sheet the Roof?
Re-sheeting the roof and rebuilding the roof structure will, of course, increase the roof replacement cost. But considering the state that we find roofs older than 50 years in, skipping re-sheeting will result in a fragile roof. It helps to think of re-sheeting as future-proofing your roof. Typically, a residential roofing system can be replaced once without removing the decking material. Depending on the type of roofing that will be installed, the replacement substrate will stay on for another 40 to over 100 years.
Tony’s Roofcare Inc. is the roofing contractor to turn to if you have a leaking roof or if you need a new one. Give us a call at (253) 200-4597 or fill out our contact form to schedule an appointment.