Dear James: We just found a house to buy, but it has a synthetic stucco exterior. What are some of the typical problems with this and can we strip it off an apply real stucco? — Lori M.
Dear Lori: There have been many stories about problems with the synthetic stucco used on the exterior of a house. Enough of these horror stories are well-founded so you are correct in showing concern. In some homes, the lumber studs inside the walls were completely rotten and there was very little supporting the walls.
Another related problem is the mold and mildew growth as the damp wood rots. Some types of this mold, often called black mold, are a real health hazard for you and your children. Some insurance policies will cover its removal and repair, but not all.
The basic building concept of using synthetic stucco is good. Exterior insulation is often used on the walls and it is covered with synthetic plastic stucco. This stucco looks and feels like real cement stucco, but it is moisture-proof. Cement stucco is waterproof and rain will not pass through it, but it is not moisture-proof. Water vapor can escape through cement so the wall will breathe.
This moisture-proof property of synthetic stucco is good if it is applied properly. The problem arises if there are just a few leaky spots, often around windows and doors. If moisture gets into the wall behind the stucco during a rain, it is trapped. Over time, mold and rotting starts.
The home you are looking at may be fine, but it would be wise to have the synthetic stucco removed. After an inspection is done to assess the condition of the lumber inside the walls and the sheathing, it can be finished with real cement stucco, brick, synthetic stone or any combination of them.
Real cement stucco can be tinted. This can be particularly attractive when it is used in combination with the stone or bricks as accents. The color also goes throughout the stucco, so there is much less maintenance required to keep it looking good. This is certainly a lot less work and expense than having to paint plain stucco after it is applied.
Get some quotations from contractors on inspecting the interior of the walls and on removing and replacing the synthetic stucco with real stucco. You might be able to convince the current homeowners to pay for the inspection since they will run into these same concerns from every potential buyer.
Depending of the current level of wall insulation, you may decide to add more. Applying the insulation to the exterior of the house is the most efficient location for it. Many of the rigid foam board insulation manufacturers have responded to the moisture problem by putting vertical grooves in the back of the board. This allows moisture to drain down and out.
If you are just going to have new cement stucco applied over the sheathing, adding a layer of felt paper will provide a good moisture barrier. For extra insurance against moisture problems, nail thin wood strips over the felt and cover this with galvanized mesh. This will create a channel for moisture to escape. The cement stucco will be applied over the metal mesh.
Send your questions to Here's How, 6906 Royalgreen Dr., Cincinnati, OH 45244 or visit www.dulley.com. To find out more about James Dulley and read features by other Creators Syndicate writers and cartoonists, visit the Creators Syndicate website at www.creators.com.