A typical residential roofing system consists of several layers of material. Depending on how the roof is built, the difference in the expansion and contraction rates between these layers could result in a condition known as roof substrate movement. Your local roofing and vinyl window installation expert, Timberland Exteriors, takes a closer look at roof substrate movement and how it can be prevented.
The Causes of Roof Substrate Movement
To illustrate roof substrate movement, Timberland Exteriors takes a look at the way roads are built. During construction, concrete blocks are laid down in such a way that there are gaps between each block, which are later filled with asphalt, a softer material. These gaps allow expansion without the concrete blocks pressing into each other, preventing potential cracks and bumps on the road.
Roof substrate movement works the same way. The substrate or decking material, typically plywood or oriented strand board (OSB) expand and contract when exposed to heat, resulting in roof substrate movement. If these substrate panels are installed too close to each other, they could push into each other as they expand from the heat, resulting in buckling. As they contract from the cold, the panels separate, taking the asphalt shingles with them and causing cracks. In some cases, the damage is so severe that the level of required repair work is almost on the same level as storm damage restoration work.
Preventing Roof Substrate Movement
Proper installation technique, like what we ensure at Timberland Exteriors, is essential in preventing roof substrate movement. The roofing contractor must supply substrate that’s normalized with the right moisture content before installation. Too dry and it can readily expand as the humidity rises. Too wet and the outer layer of shingles will drift and crack over time. Correct installation techniques, such as proper spacing between substrate panels, correct attic ventilation and use of moisture-resistant underlayment, can go a long way in minimizing the effects of roof substrate movement.
To learn more about our roofing services, as well as the better solution to vinyl siding installation, call Timberland Exteriors today at (651) 404-2330 (St. Paul), (952) 373-5145 (Minneapolis) (218) 366-9433 (Detroit Lakes), or (715) 203-8040. You can also fill out our contact form to schedule your free quote. We serve St. Paul, MN, and surrounding areas.