Pest control reports, damaged wood behind stucco and stucco hole testing.
Stucco is one of the most durable exterior wall finishes available. If applied properly it will protect your home from the harsh elements for decades. Stucco is used on the exterior of all types of homes. From entry level bungalows to Piedmont estate properties. Stucco is made from sand, cement and lime all mixed together then applied to a surface in stages. It can be worked into many different textures and finishes. It takes 21 days for stucco to reach its maximum strength and once it is fully cured it will last for years.
Here is the typical process of a stucco application. A wall is framed with wood studs. Another layer of wood is fastened to the studs. Back in the day a 1 by material was used. Newer construction now calls for plywood. Plywood is lighter, less expensive and also gives additional seismic strength. A heavy paper is rolled over the sheathing and stapled to the surface. It is this paper layer that provides the moisture barrier protecting the wood from becoming wet and damaged over time. Heavy gage wire called “lath” is then fastened over the paper. The stucco layer is then applied in stages as wet mud and is pressed into the lath. A fist layer is called a scratch coat, the second is the brown coat and then finish or texture coat is applied. Over time the paper layer can break down and begin to let water get underneath it. The only way to determine if there is damage to the wood below the paper is to have the pest inspector do what is called a stucco hole test. Starting low, the inspector hammers small holes in the stucco and then pokes around to see if the wood is damaged and how deep the damage extends.
Homes built with parapet walls at the edge of the roofline are notorious for allowing water entry. The susceptible spot is the flat area on top of the parapet. Over time the sun bakes the top of the parapet and allows rain water to enter behind the stucco paper. Any property with this type of detail should have a stucco hole test performed. As a home owner, at a minimum you should have the parapet checked annually for water tightness or better yet hire a roofer install a solid metal flashing cap over the top of the parapet.