A newer basement may have walls and ceilings that are solid and secure. Older basements often have problems that must be attended to. In some cases, the fixes are fairly quick and easy; in other cases, serious surgery is called for, which can be performed only by professionals.
If brick, stone, or block shows signs of surface deterioration, the problem is very possibly only deep. As long as the wall as a whole is plumb and free of bulges or indentations and the floor above is not sinking, damage like this can be fixed by filling in with mortar.
Problems with basement walls and floors— often called a house’s foundation—are visible not only in the basement itself but also on upper floors, as shown in the drawing. When these problems manifest themselves, you should take steps to fix them in a timely manner, or they can get worse and damage the rest of your home. They certainly should be repaired and shored up before attempting any basement remodeling—which can often cover up the problem, so it grows worse when out of sight. In general, look for cracks that are wider than 1⁄4 in. or that are offset. Also, see if your walls or floors are uneven.
If cracks in a basement wall are uneven or offset, like those shown here, there could well be a problem with the underlying concrete or stone footing. This problem will not fix itself and is likely to get worse. Has it looked at by a professional?
The drawing shows other signs of structural problems. If a chimney leans so it pulls away from the house at the top, the problem may simply be with the chimney. Or, it could be that the foundation it rests on is sinking or leaning. This can lead to damage to your house’s siding and even its structure.
WARNING: If a floor has a crack wider than 1⁄4 in., or if it is uneven so that one area is more than 1⁄2 in. higher or lower than an area less than 8 ft. away, the basement floor is likely in trouble. However, unless the floor is separating from the wall, the problem can often be solved by reinforcing the floor, perhaps by adding another layer of concrete. Or, you may need to break out the old concrete and pour a new floor.
Crumbling and falling ceilings
Older basements with lath-and-plaster ceilings often end up looking something like the photo at right. If the damage is not severe, you may be able to “skin over” the ceiling by attaching sheets of drywall that hold the old material in place. However, if it looks like this or worse, you should remove the plaster and the lath—an extremely messy process, so wear a respirator and ventilate the basement with outward-pointed fans as you work.
Old plaster often fails in a basement. Depending on the amount of damage, you may repair, replace, or cover over it.
Bowed walls are a sure sign of trouble. Hold a 6-ft. or 8-ft. level against the walls at a number of places. The walls should be reasonably plumb (though they do not have to be perfect), and they should be straight. If you see a bulge, or if a wall is out of plumb by more than half the level’s bubble, call in a basement expert for assessment.
If you see gaps under baseboards—either in the basement or on the first floor—that means the floors are sinking, which most likely means that the house’s footing is sinking. If the gap is more than an inch, the problem could be serious, and you should have the house’s footings inspected.
If windows or doors in the basement or on the floor above are noticeably out of square, they will not close properly. The problem could be that the house’s foundation is sinking in some places. You could reinstall the windows or doors, using shims to keep them square, but the underlying problem may remain and get worse. The foundation likely needs to be fixed.
If cracks like this near a window develop on the first or second floor of the house, have the foundation inspected. This is often a sign of a sinking footing.
Solving Foundation Problems
Unfortunately, foundation repairs are not do-it-yourself projects. Find a company with a long history of foundation repair in your area. The company should have plenty of references you can call, and the salesperson should explain clearly the type of work they will do. Two common repairs are adding carbon armor straps and neckties.
If a wall is bowing in the middle due to soil pressure, the bowing can often be stopped with the installation of special foundation straps that are typically made of super-strong carbon fiber. These can be installed quickly and on the inside of the basement, so no excavation is required. They can be painted over or hidden behind walls that you frame out.
If an entire wall is leaning at its top, the process can be stopped by the use of a foundation strap with the addition of a necktie. Made of exceptionally strong Kevlar® or fiberglass, a necktie is bolted with special hardware to the outside or rim joist, to hold the wall in place.
If the floor is sinking, the foundation likely needs to be raised and reinforced. A basement repair company can insert foundation piers.
A carbon strap won’t fix a bowed wall, but it will stop the wall from continuing to bow. The strap—and bowed wall—can be hidden behind drywall.
A floor that is 11⁄2 in. below the bottom of the wall (left) has sunk and needs to be raised and reinforced. After raising the foundation with a foundation pier and supporting it by pumping in concrete, as shown on, the floor is brought up to meet the wall and will not sink any farther (right).
WALL ANCHOR SYSTEM
Straps and neckties stabilize walls that lean slightly. But if a wall is leaning or bowed seriously, and you need not just to keep it from getting worse but to actually move it into a better position, then solutions from the outside are called for. A wall anchor system can be installed with surprisingly little disruption to your yard.
With almost surgical precision, heavy-duty wall anchors are inserted into the soil and secured with threaded steel rods that poke into the basement. Inside, you see a series of wall plates. Bolt heads on the plates can be turned to adjust the wall’s position.
Installing wall anchors
Companies that specialize in repairing bowed and damaged basement walls have developed methods to limit the damage to interior walls and the lawn outside. Here are some techniques used by the Perma-Seal company in the Midwest. There are likely companies in other areas that follow this or a similar technique.
- Using heavy-duty drills and massively long masonry drill bits, holes driven through the interior wall are generally only 2 in. or so in diameter.
- Through experience and some calculating, the workers know pretty much where the drill bits will end up on the outside. Holes are dug from those locations.
- Here, I see that the sod is neatly cut out so it can be replaced later. Large threaded rods are pushed through the hole in the interior wall to the outside holes, where they are attached to wide plates.
- From the inside, the threaded rod’s hole is filled with a very strong epoxy that keeps out any possibility of moisture infiltration.
- A large plate is attached temporarily while the wall is ratcheted back into straight vertical.
- The plate is left in place. It may need adjusting in the future. You may leave it exposed, or cover with framing and drywall.
If your walls and floors are sinking, the concrete footing they rest on is likely sinking. Believe it or not, footings can be raised. However, this is the most extreme repair, involving digging a wide trench around the house, inserting a steel push pier deep into the ground next to it, and raising the footing up with steel brackets attached to the pier.
The process can take some days, as the footing is raised slowly with hydraulic pressure. Once raised, concrete is pumped into space under the footing, and the house will remain stable for a century or more to come.