Stucco Parapet Maintenance

With flat roof architecture, this stucco to roof transition also known as the parapet, is the most problematic with regard to periodic maintenance.

A typical stucco system on most wood framed  homes includes, a moisture resistant barrier of asphalt impregnated paper over a wood sheathing, stucco netting, cement base coat(s) and a cosmetic colored stucco finish coat also known as a color coat. This stucco system will perform well under most adverse weather conditions but is not designed to be a “waterproof system”.  By design, homes in the Southwest have parapets and flat areas that allow water to be retained and undergo freeze thaw cycles.  This action breaks down the stucco and will eventually cause cracking, deterioration, and eventually leaks through the stucco.

With an existing stucco system or even a newly applied cosmetic stucco color coat, the parapet requires annual homeowner maintenance to insure a trouble free system.  Understanding that cement stucco will crack and roof flashings will breach, the following maintenance regiment is recommended; 1) Seal any visible cracks on the parapet with an acrylic/ silicone or a polyurethane caulking. Polyurethane caulk is preferred but a bit messier to work with.  For additional caulking recommendations, please see the accompanying “Caulking of Stucco… Tech Bulletin”. Keep in mind that it is best not to extend the caulk too far over the front face of the parapet, where it will be visible from below and 2) Re-seal the roof flashing to the parapet. This is typically accomplished by applying plastic roof cement to any breaches or breaks that are evident at the stucco to parapet transition. A silver paint sprayed over the plastic roof cement will help to extend the life of the product.

If these maintenance items have been accomplished and you are still experiencing problems, testing of the roof is in order. A competent roofer may conduct a test by flooding the roof and flooding any other transitions to roof penetrations with water to pinpoint a roof leak.

Copyright 2011. Reule Sun Corporation.