23 Feb How to Repair a Sinking Floor

A sinking floor is disturbing and dangerous. Before embarking on a course of action to rectify the problem, it’s essential to ascertain the reason for the sagging and its severity. While it’s possible for individuals to fix the problem themselves, it’s really best to hire professionals that have experience in the field.

The most common reason for a sagging floor is a flaw in the design that doesn’t provide adequate support for the flooring. Enough floor joists may not have been installed when the home was built. Over time, homes settle under the weight of furnishings, which can be traced to a problem with joists. The flooring may also have been subjected to flooding or a damp crawl space may be the culprit.

Identifying Areas of Sag

A floor typically won’t exhibit sag across an entire room or the home. One method for detecting sagging is to measure the floor-to-ceiling distance over where the sagging is most noticeable. A carpenter’s level may be used instead to detect the primary area of sagging.

Individuals should also get under the floor for a visual inspection to see if there are any cracked, rotted or broken joists. There are a couple of options for sagging floors if the joists are old, losing their strength or cracked. If the problem is due to moisture, the area will first need to be dried out. Wood is a porous material and easily absorbs moisture.

Repair Options

Individuals can provide extra support for sagging joists with a floor jack. A 2×4 is nailed to the underside of existing joists at their point of sag. The jack is then placed under the sag point and jacked up about 1/8^th of an inch per day until the floor is level.

A concrete or block support can also be placed underneath the sagging joist to hold it in place and prevent further damage – providing the amount of sag isn’t extensive. Using a sister joist is another alternative. A new joist is installed next to the one that’s sagging and the two are connected with screws or nails.