Causes of Warping on a Roof Deck

Poor Ventilation

• If you see the boards on your roof deck are buckling or uneven, warping has occurred. When boards or wood warp, their original shape has shifted or curved upward, making them unable to continue to support the structure. One reason for warping could be poor ventilation within the roof. As moisture begins to build up in the attic area, condensation forms, which can find its way into the space between the ceiling and the underlayment of the deck. If the deck is ruined from moisture and warping, it will need to be replaced along with wet wood and materials from the roof and attic area.

Poor Construction

• If your rooftop deck was not properly installed, it could lead to water damage, resulting in a warped deck. If you walk across it and notice bowing, the boards could be warped. Poor construction may include failure to install plywood clip spacers between wood. Lack of spacers causes the wood to swell and eventually warp and ruin the surface of the roof deck. If new shingles were placed over old ones that were breaking or leaking, the damage could reoccur by warping the deck wood that is overtop the shingles.

Improper Drainage

• If your roof does not drain properly, you could have water that builds up underneath your deck. The result of water buildup can damage your roof, deck underlayment and the deck itself. Making sure you have gutters installed around the roof area will make it easier for water to run off. Essential for proper drainage is to make sure your roof is not completely flat or that you have spill-off area to prevent puddles of water from building up.

Old Materials

• If your roof or roof deck is made from material beginning to show signs of structure wear, it may be time for a replacement. Over time, wood will warp if damaged. When replacing old wood with new, make sure you install treated, mildew-resistant lumber. Check to make sure the support structure beams are not warped and are free from mold and mildew.