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Why are my Garage Walls Wet?

There are many potential causes for wet garage walls, and as the water can travel quite a distance from its origin, identifying the cause can be sometimes more difficult that resolving the issue itself. Below we will list some of the main causes of wet garage walls and the best solutions for them.

The Roof

Wet walls can often be caused by a leak on the roof. This can be identified by wet wooden joists acting as a conduit for the water. The flashing where the walls and roof meet is a common site of entry, as are any flaws in the roofing materials. These should be checked and replaced.   

Seal the seams!

Window, door, and utility seams are all potential entry points for water and should therefore be sealed with a silicon caulk. The seam between a wooden internal wall and concrete floors, walls and ceiling should also be sealed with silicon caulk to prevent water ingress.

Humidity and Condensation

High humidity levels or condensation can create wet walls which give the appearance of a leak. The condensation could be caused by uninsulated pipes in the walls, whilst high humidity is likely in garages with many concrete walls. To determine whether humidity or condensation is the problem, tape a piece of foil to the wall and leave for a few days. If the moisture is on the wall side, it is condensation, if it is on the other side, humidity. To stop the condensation and humidity, seal the concrete walls with a penetrating sealant, improve ventilation with vents and control the temperature better by insulating the garage.

Cracks in the concrete

This is especially a problem in garages which are below-grade. Concrete is porous and therefore moisture can travel from the outside into the garage, leaving the walls damp with moisture. To resolve this, make sure any cracks and crevices are filled with hydraulic cement and that the entire wall is then sealed with a penetrating sealant. This will prevent moisture from travelling through. It is also recommended to divert water away from the garage, so install gutters and drains to help keep water away.

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