Monday, January 26, 2015

Rainscreen Mold Prevention

Rainscreens alow rain to pass by exterior walls without soaking through.


A rainscreen is a particular building method that seeks to both protect an exterior wall and prevent certain kinds of water damage, including damage caused by mold that loves to seek out moist places to grow. Rainscreens can be made of many different materials, but the most common types are made from stone or brick veneers that are placed over screen meshes and other materials to form the rainscreen. If you live in a damp climate and have exterior, stone-based walls, these screens are a dependable way to prevent mold damage. Does this Spark an idea?


Rainscreen Construction


The rainscreen does not simply protect against falling rain. No matter how durable the surface is, some water will always seep through, and it is this water that causes mold problems when it seeps through the rainscreen and dampens the exterior stone beneath it. A properly constructed rainscreen will not allow this, so when you are planning your rainscreen, make sure it is made properly. A real rainscreen will have a space between the stone veneer that faces the rain and the exterior wall of the stone itself. This forms an important drainage plane and airflow region.


When you create your rainscreen, ensure that any water that comes down or seeps through the screen has a clear and unobstructed pathway to flow straight down into the ground and away from the wall itself. The longer the water spends in the small space between the rainscreen and the wall itself, the more damage it can do. It is equally important that the air outside is allowed to flow through this space. This air must access all points between the rainscreen and the exterior wall surface so that it can move freely and dry out any leftover moisture.


Rainscreen Materials


Although you can test your rainscreen as you make it or hire a contractor that specializes in making real rainscreens, choosing the materials is just as important. The better the materials, the longer your rainscreen will last and the better it will be at mold prevention. Use exterior moisture resistant construction paper or sealant on the stone wall itself before you even being constructing the rainscreen. It is important that the wall resists the moisture that passes by it even for a brief time while it leaks down to the lower part of the rainscreen and is released.


Check with local building codes to see if they say anything about constructing rainscreens. In Canada, for instance, rainscreens are mandatory in some locations. Choose rainscreen materials that are mold and mildew resistant and will not corrode. If you use steel mesh, make sure that is rust-proof, and seal the stonework in place with waterproof adhesives.

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