Artificial stone is not waterproof
best practices when working with artificial stone, real stone, concrete block or any other exterior masonry material.
Builders hundreds of years ago knew that brick leaked water. This is why they used different types of brick to build solid-masonry buildings.
The brick you see on the outside of the structure was fired harder and longer in the kiln and didn’t normally absorb much water at all. But the brick used behind the face brick was a softer brick that was quite absorbent.
When the rain got past the outer layer of brick through the mortar joints, the inner layer of brick acted like a temporary reservoir. As soon as the rain stopped and the sun came out, the water inside the brick wall would wick out to the atmosphere. It was an ingenious system learned no doubt the hard way over a few centuries.
Today brick or stone is almost always a non-structural element on homes. Extra care has to be taken to build the home so the water that gets through the mortar is collected and redirected to the exterior without ever touching the wood framing. All of the methods to achieve this goal are outlined in the technical notes you, your builder and any mason can get from the BIA.
Amanda’s artificial stone dilemma is not easy to rectify. The best way to solve the problem is to remove all the stone and start over with the correct detailing, using waterproof membranes and flashings above and below all windows and doors. But this is not realistic. Very few people can afford to do this, and Amanda’s builder is not going to do the honorable thing and correct the problem.
Amanda will probably have to apply several coats of a silane-siloxane water repellent on her stone facing, but this might solve the problem. If not, she may have to apply a thicker clear sealant that’s brushed on the mortar and overlapped onto the artificial pieces of stone.
How can you avoid becoming a statistic like Amanda? It’s not easy.
You need to have fantastic plans and written specifications to start. Another key point is to have a meeting with your builder before he bids the project, review every aspect of the house and make sure he understands what needs to be done. Include great photographs with your plans, if you can get them, showing exactly what you want each part of your house to look like when complete. These photos help communicate the level of quality you expect.
Be sure you include a penalty clause so each day the builder is late, you deduct a certain amount from his final bill. Don’t get trapped into giving the builder more money at any point than he deserves. If you do this, there could still be $80,000 worth of work to do but only $40,000 in your construction loan account.
Be careful!