Manage PVC Trim Expansion
Properly install PVC trim products during cold weather to prevent expansion, contraction, and bowing issues. Warm up the trim before installation for better results.
As a siding contractor working during a Minnesota winter, I had to be careful when installing products that have a high rate of expansion and contraction with changes in temperature. Trim products made of PVC are definitely in this category—if you install a PVC garage-door weatherstripping when it’s 1°F outside, when the weather warms up that weatherstripping will expand and likely bow out between the fasteners. Longer lengths and dark colors in the direct sun are particularly susceptible.
I’ve learned that whenever possible, avoid installing PVC trim if it’s very cold outside; but if you have no choice, warm up the trim before installing it. You don’t need to get it hot; room temperature will make a big difference—just bring it into a warm house and bring it up to room temperature. The trim will likely shrink a bit when it cools down and create small gaps at the joints, but those are much less visibly offensive and can often be concealed with elastic sealant.
—Mark Petersen, Waco, Ky.
Illustration by Charles Miller