Controlling Water Penetration

 Figure 1

Rain and ground water are major deterrents in keeping a home durable and healthy. Mold is one of those words that make everyone cringe. Through best practices and attention to detail, water can be kept out of the building assembly and prevent mold issues. Sounds easy, right? Unfortunately things are often overlooked. I find that common knowledge suggests that siding is all the waterproofing that is needed. Today’s siding materials do shed most of the rain water. Notice I said “most”. Some water will penetrate the siding especially in transition areas. It is very well know from an installer’s standpoint that this does happen. This is why it is code to use a house wrap membrane of some form to handle this exposure to water. Unfortunately this house wrap is not always installed correctly and leads to problems. Most recently we were working on the house shown in 1.

Figure 2

We were here to do some interior remodeling and widen the front entry door. When removing the siding to have access to the wall to modify the opening, we found something disturbing. The wall sheathing was falling apart behind the siding. We continued to remove siding to expose the problem. In 2 and 3 you can see what we found.

A closer look at 3 shows the lack of proper flashing. Just above the siding you can see a narrow strip of white. That is the house wrap material that is designed to protect against water infiltration. You can see that the roof assembly is shedding water directly behind this membrane. After removing all of the damaged sheathing and replacing with new, we installed a piece of flashing behind the roofing assembly and over the house wrap to provide a continuous drain plain for the water to follow. This would have taken the builder 5 minutes to do and would have prevented this from happening in the first place. Unfortunately they did not, but fortunately we found it and were able to correct it. The disturbing thing is that three different trade professionals would have been working in this area. The carpenters, siders and roofers all overlooked the lack of proper flashing.

Figure 3

It is important to have the right people involved that would have noticed the problem and corrected it or found someone who could. We are all human and make mistakes. We need to have relationships with our trade contractors to hold each other accountable. We should all be looking out for the customer and providing them with the best finished product we can.

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