Settling requires structural repair and, legally, a permit

Q: My home was built in 1953 on post-and-beam foundation. A new torchdown roof was installed seven years ago. Recently, the back door and a nearby interior door have been binding at the sill and floor, indicating possible settling. I checked the 30-inch-high crawlspace and found the cement floor was wet under this area, although the remainder of the crawlspace was dry. What is wrong, and how do I proceed?

A: Your suspicions about the relationship between the door binding and the settling are spot-on. And yes, the water you see undoubtedly is related, for two distinct reasons.

With posts as the sole source of support, you have no traditional foundation wall to keep water out of the crawlspace, and no foundation to spread the weight of the building across a large area. Therefore, you are more vulnerable to leakage, settling and wood deterioration than you would be in a home with a perimeter foundation.

In place of a perimeter foundation, undoubtedly you have some sort of skirting system that rests in or close to the ground to keep rats and other intruders out. While not structural, these skirting systems typically deteriorate, due to their close proximity to dirt and water.

Groundwater, downspout runoff and downspout leakage are the main contributors to skirting and structural post damage. One of these will be the source of the water you see. Very carefully check, during rain or with a hose, to see that the downspouts and roof scupper above are not leaking as they run down the sidewall. Also make sure that once the water hits the ground, it is not running back toward the building. Once you have determined the water source and helped prevent it in the future, you can repair the settling.

Here is the first settling scenario (wood rot): Ideally, your supporting posts rest on concrete piers or blocks that are well out of the path of dirt and water. But they might not be. And ideally, the concrete floor you describe is not poured directly around the posts; concrete will hold water against the wood and cause it to rot.

In those cases, you undoubtedly will have wood rot. The jaffected post(s) will need to be replaced, the home gently jacked back up and firm support from beneath installed if necessary (a new concrete block or pier). Alternatively, after post replacement, the concrete and dirt are pulled out of harm's way if support is adequate beneath.

Second scenario: When the posts are up out of the path of direct deterioration by water (but water pools beneath as you describe), you will incur settling as a result of movement of the supporting soil, not because of wood deterioration. This is the type of settling seen on homes with conventional poured-concrete or block foundations. The soils compact, consolidate and wash away under the influence of water, allowing the concrete pier or block to settle.

Post and pier foundations are more susceptible to this type of settling since they typically are not dug as deeply into the ground and into firmer soil that is less prone to movement. Typically, their supports are resting just below the surface, where they are more vulnerable to freeze/thaw movement as well. This will require some digging to get the concrete block or pier well below present level into firm soil at least 24 inches down.

So where to turn? Most of these repairs are pretty straightforward and require no specialized diagnostic skills, repair techniques or knowledge. Quite honestly, in my experience, more than 90 percent are done by general contractors, homeowners and handypeople — without permits. Most are done quite well and are a vast improvement over the original construction techniques, both in method and material.

But does that mean it's legal? No, it does not. This is a structural repair and therefore requires engineering, plans, permits and the whole ball of wax.

Fulfilling the obligatory requirements generally exceeds the cost of the repair, which means a lot of these are done under the radar with a wink and a nod. If that is the route you choose, make sure you disclose that fact to potential buyers of the property down the road.

Darrell Hay is a local home inspector and manages several rental properties. Send questions to dhay@seattletimes.com or call 206-464-8514. Sorry, no personal replies.