Q. We recently purchased an older home. The living room floor sags noticeably in the center. A friend of ours says the floor joists probably need to be replaced. Is this the case?
A. When sections of flooring become uneven, usually a problem in older homes, the cause is seldom the joists but more often the weakening of the girder or supporting post.
One remedy is to add another post directly beneath the sagging section of girder. Rent a shoring jack and use it to raise the girder to level, plus a fraction of an inch more to allow for settling. Raise the jack gradually, a partial turn or so per day over the course of a week or more. Adjust the height of the new post and make sure there is solid footing beneath [a 20-inch-square concrete slab 10 inches thick is standard].Then fit the post, check that it is exactly vertical and lower the girder onto it as you remove the jack.
Sometimes all that is necessary is to place shims between the girder and existing posts, using the same jacking method.
To determine the amount a girder must be raised to level it, stretch a string along one side of the beam, from the bottom corner at one end to the bottom corner at the other. The amount of wood showing below the string [where the sag is most extreme] is the distance the girder must be raised.
Q. We remodeled our kitchen and replaced our 40-gallon, gas-fired water heater with an electric water heater that has a 5,500-watt element. When our three grandchildren come to visit, the water is not hot enough for them to bathe at half-hour intervals, like they did when I had a gas-fired water heater. Can you help?
A. People switching from a gas-fired to an electric water heater frequently cite this problem. When selecting a water heater, consider its capacity and the recovery rate. The recovery rate is the number of gallons that the unit will heat to 90 F to 100 F above its inlet temperature in one hour.When the tank capacity is low, to have an adequate supply of hot water, the unit must have a high recovery rate.