Stand outside by each corner of the house in turn and sight down the line where the framework meets the foundation to see it’s straight. If it’s an older house that has already seen weather and has had a few years to settle, and there’s no apparent sign I structural deformation, then that’s a good sign. Foundation problems are hard to conceal, simply because they affect the very shape of the house itself.
Every house has a frame. The frame is usually made of large numbers that support the building and that the foundation, siding, roofing, and sheathing are attached to. Some of the earliest American houses were framed with the post (vertical member) and beam (horizontal member) construction favored for centuries by barn builders.
An alternative method introduced late in the last century is called balloon frame because carpenters who were accustomed to post and beam construction thought of houses built in this way as being held up by nothing but air. A friend of mine lived happily for years in such a house, however, and thousands of balloon-frame houses are still standing despite the fact that they often have insufficient timbering to meet today’s building codes.
This method may have achieved its considerable popularity because it enabled carpenters to build a house with less wood than was required for a post and beam frame, and thus to save on construction costs. But there was precious little science to house carpentry when this technique was introduced. If a building stood the test of time, the construction technique was considered proven. Nobody had to worry back then about heavy hot tubs, waterbeds, and the like, and nobody would have thought of removing interior walls from such structures without adding additional support. In any case, many balloon-frame buildings today show signs of insufficient structural support.
How do you tell if your prospective dream house is in this category? A building with too little wood in it will have bouncy foors. Go to the middle of the room and jump up and down. If the floor moves appreciably, chances are that either a wall is missing underneath it or the joists are undersized.
Another tip-off will be window and door openings that are out of square; if the building is sagging, windows and doors won’t close properly. The most obvious symptom of weak structure is often the ridge of the roof. It should be perfectly straight; if it isn’t, make sure to have the inspector (see chapter 11) find the cause.
A third construction method is the platform or “Western frame” method, in which a deck is built and rests on the foundation. From there up to the second floor, stud wails are built, then another deck is added for the second floor. Another stud wall carries to the roof level, and then the roof rafters are added. Most homes built today use this method, which results in a good strong frame. Houses built this way are also the easiest to modify after the fact.
What do you do if’ a house you’re interested in shows signs of structural weakness? Don’t walk away from it. You may be surprised to learn that structural problems can often be corrected in straightforward, effective, and relatively inexpensive ways. Often the problem can be fixed by simply placing floor jacks where the added support is needed. Bouncy second-story floors are harder to deal with because no one wants floor jacks in their living room, so the added strength has to come by adding thicker and wider timbers alongside the originals. This “sistering” technique works fine as long as there is enough space for the new lumber. Our “This Old House” team once took the roof off a nicely built ranch-style house, added hefty timbers where the old ceiling joists used to be, built a platform or deck structure on those timbers, put stud walls on top, put in a system of trusses to carry the weight of a new roof, and thus successfully transformed a simple ranch into a two-story garrison colonial.
Another common solution for structural weakness, or for those occasions when renovations call for expanded openings in the frame, is to use steel or glue-laminated I-beams. Old-time carpenters employed very little steel in residential building, but its use today is widespread because it makes possible easy solutions for otherwise quite impossible problems.