It depends on the age of your home. Old foundations were prone to movement, and the support posts in damp basements were prone to rot. But new foundations rarely move, and modern construction techniques keep basements dry. So, if it’s new, your house probably isn’t settling. Then why, in nearly all newer homes, do we find cracks in the walls and gaps appearing along trimwork?
The answer lies in the kind of wood from which modern lumber is made. Older lumber was comprised of mainly “heartwood,” the center portion of the trunk of a tree. In a tree, this wood’s function is to provide structural support, and its composition makes it resilient to water and insect damage. Modern lumber is comprised of a greater amount of “sapwood.” This is the outer portion of the trunk where water is transported. You can think of its composition as a collection of straws where water can easily flow up and down the length of it.
Since sapwood contains a lot of moisture, it will shrink considerably as it dries out with time. This shrinking is the cause of those cracks and gaps inside your home. While these flaws are frustrating to look at, they don’t compromise the structural integrity of your house. However, if you are seeing shrinking inside your house, it may be signaling the potential for bigger problems on the exterior of your house.
Remember those “straws” in the sapwood? When exposed to the elements, they can readily absorb water, which can encourage rot. Areas of concern include trim work around windows and doors, skirting, and porch columns. Even if your house is newer, you should inspect these areas to make sure there aren’t early signs of water damage.
If you are in need of repairs or are dealing with new construction, make sure to discuss with your contractor or builder what options are available to ward off exterior rotting issues. At the very least, he should make sure the materials in use are properly sealed before work begins. He may be able to use engineered materials. Exotic woods tend to be more resistant to water damage, but these may have environmental concerns attached with their use. Since watershed is really the key issue, your contractor can use innovative designs to assure that water runs off the exposed area rather than pool up on it. Your contractor should be open to this discussion and interested in sharing what techniques he is employing to preserve exterior areas of your house.