Your old house has started to crack, but you needn't

HOMEWORK

November 28, 1999|By Karol V. Menzie and Ron Nodine

IF YOU OWN an old house you are undoubtedly interested in why you have cracks in your walls and how to fix them. Cracks are alarming, and while they're not usually serious, sometimes they are the result of deterioration that needs to be checked.

Cracks are usually caused by settlement, but not necessarily. Expansion and contraction can cause them, as can inadequate framing members.

Houses move with the climate: Heat and moisture will make them expand, cold and dryness will make them contract. This movement is normal and in most cases will not cause cracks.

However, when walls get old and brittle, after many years of being stressed by the movement, they will break down at their weakest point, hence the cracks.

Settlement cracks are caused either by the foundation moving or the framing members sagging because they are spanning too long a distance, or supporting more weight than they are capable of.

The sagging-framing-type problem is most common in houses dating to times before building codes were enforced, or even before they existed.

Ron just finished a renovation on an old farmhouse, apparently built by the farmer, which had just such a problem. The second floor joists were only 2-by-8s, set 24 inches apart, and spanning 17 feet from support wall to wall.

The most a 2-by-8 should span is 12 feet. (The rule of thumb to calculate a span is 1.5 times its height, so 8 plus 4 equals 12 feet, with standard 16-inch spacing) The result of this was a floor that looked like a soup bowl.

The center of the floor was a good 5 inches lower than the perimeter. (Ron and crew added a new center beam, but that's another story. We'll be doing a future column on this project and will tell you the rest then.)

When foundation settling is the problem, you can correct it.

Usually, the most cost-effective way is to leave the foundation alone and jack the framed part up to its original position. Then you can repair the cracks and hope it doesn't settle any more. You have to leave the jacks in place, or shore up the beams.

Some minor settlement is normal. Old houses usually have settled as much as they ever will, unless there is some other cause, such as erosion, causing it.

It does happen, though. Ron had an interesting experience with a house in Parkville, where he built an addition on the back.

There were existing cracks in the dining room adjoining the addition. Assuming the house, about 60 years old, had finished settling, he repaired the cracks with the other work. A year later the cracks were back, and the door on the adjoining wall was sticking.

Ron assumed the new foundation had settled and that was causing the problem. But there were no cracks in the foundation where the new and the old parts met.

If the new part had settled, there should have been at least a hairline crack.

As it turned out, rather than the new foundation sinking, the old foundation was actually rising.

The motion apparently was related to the water table beneath the ground rising and falling according to the amount of rainfall in a given period.

Although common in some places where the water table typically is closer to the surface, this is an extremely rare occurrence in this region, and baffled Ron and his client for some time. Cracks, like leaks, can be tough to fix, because the causes are mostly invisible. Yours may be simple, but don't count on it.

Next: How to fix cracks, including those in foundation walls.

Ron Nodine is owner of American Renovator Inc., a Baltimore design-build remodeling firm, and former president of the Remodelors Council of the Home Builders Association of Maryland.

Karol Menzie is a feature writer for The Sun.

If you have questions, tips or experiences to share about working on houses, e-mail Ron at hw@renovator.net. Or write c/o HOME WORK, The Sun, 501 N. Calvert St., Baltimore, MD 21278.

Questions of general interest will be answered in the column; comments, tips and experiences will be reported in occasional columns.

Baltimore Sun Articles
|
|
|
Please note the green-lined linked article text has been applied commercially without any involvement from our newsroom editors, reporters or any other editorial staff.