Installing a great-looking TPO or PVC roofing system starts before the first fastener is screwed into place, a drop of adhesive is applied, or a single inch of release liner is pulled back. It begins with how the membrane rolls are stored.
If stacked too high and not properly rotated, TPO and PVC membrane rolls can be flattened into an oval shape. This can result in blocking – a waviness in the sheets that can make welding more difficult. This is particularly true if the rolls are stored outdoors for an extended period in hot weather.
The good news is that blocking is an aesthetic issue only. It does not impact the membrane’s performance or durability. And the waves will dissipate on their own over time.
The better news, though, is that blocking is easy to prevent. Four-packs of membrane rolls should not be stacked more than five high. Stock also should be rotated every 60 days or whenever new material is received. The oldest stock should always be used first.
Small stacks. Regular rotation. Simple steps to help ensure a tight, professional-looking roof that the crew can take pride in and the property manager can be confident singing off on.