Stucco provides a beautiful and durable exterior finish for any home or commercial building, but it can and often does allow water penetration which can lead to serious water damage in exterior walls. Stucco leaks can remain undiscovered for years, resulting in extensive wood rot, mold growth and insect infestation.
Why do stucco walls leak?
D.A.M Home Inspections has inspected and evaluated many building leaks over several years and we see the same issues over and over.
When it comes to leaks with stucco walls, the problem is nearly always due to defects in the flashings and moisture barrier behind the stucco layer.
Stucco should be viewed as a ‘system’, not just a layer of cement material applied on a wall. Before any stucco is applied the wall substrate must first be covered with a moisture barrier and all door and window openings must be flashed and properly integrated with the moisture barrier using sheet metal flashing and peel and stick membrane type flashing.
If this is done correctly the entire wall can be made completely watertight before the stucco is even applied. If the flashing and moisture barrier are not applied correctly the wall will most likely leak in time.
Looks Can Be Deceiving
Stucco is a very attractive finish for houses. One to the problems is that only invasive testing can only truly determine the condition of a wood behind the stucco. There are instances where there is cracking and no deteriorated wood sheathing and structural members, and other times where there is a problem.
There are instances where there is no cracking and there are deteriorated wood sheathing and structural members problems.
Some stucco can appear just fine, but sheathing behind itt is rotten. Other stucco can look horrible, (cracked and stained) and the wood sheathing behind is sound. The Only way to know is to probe the wood with twin probes that are 1/8” in diameter. These probes will indicate the moisture content and if the wood is solid or rotten.
Our inspection is a visual inspection of both indoor and outdoor surfaces of exterior walls and includes documentation to the client as the inspection proceeds. It is intended to provide a way to find out if there are obvious defects in the stucco or visible indications of water intrusion at the indoor side of the wall. Where we find defects in the stucco on the outside we often find signs of corresponding water damage on the inside.
Our Testing Methods:
- Detailed visual examination and probing of exterior construction details.
- Identification of likely sources of leakage at exterior walls.
- Photographic documentation of relevant conditions.
- Thermal imaging of exterior and interior sides of exterior through the use of an infrared camera.
- Stucco probe Moisture Meter testing of exterior and interior walls using several different types of moisture meters.
- Moisture probe testing. Two small holes are drilled through the stucco to allow insertion of a two-prong moisture probe at locations where water penetration into the wall sheathing or framing is suspected.