Common Subfloor Problems and Solutions

From on May 15, 2009 in Flooring

feetonfloor.jpgPhoto credit: Orin Optiglot

Sunken and uneven floors can mean big problems and big bucks to fix. To troubleshoot shoddy flooring in the home, look to the subfloor for answers. This is a likely source for those pesky and annoying problems. Wooden subfloors are built in three ways: Tongue and grove panels, plank subflooring, and OSB (Oriented Strand Board) glued and nailed to joists. With the correct design and proper installation, these modern designs are durable and trouble free. But if poorly installed, a faulty subfloor makes it impossible to maintain quality floors. Here are some common subfloor problems and solutions to help restore the floor.

Sinking Floor

This could mean that the subflooring was not installed correctly. If the floor feels soft or spongy, then the subfloor is not as strong as it used to be. Water or moisture may have started rotting the joist, causing certain areas of the floor to sag. You’ll have to take a look at it, either from the basement or by removing the flooring. The subfloor can be temporarily propped up with a floor jack and then pressure treated beams can be put in place to stabilize the floor.

Creaking or Popping

This is a familiar sound in many older homes. It’s usually far too easy to just overlook, but that wouldn’t be wise. A creaking noise can mean that the subfloor is not secured to the underlying joists. It could also indicate the wrong thickness of plywood or OSB was used. The recommended width is ¾ inch. In any event, you’ll have to remove the old plywood and replace it with thicker panels. If that’s not possible, install wider joist. This tactic serves the same purpose and should stop the noise.

Uneven Floor

The foundation or support walls may have settled and left you with an uneven floor. Another possibility could be water damage to the floor joists. My first suggestion would be to get the subfloor inspected by a contractor. Replacing floor joist, beams, and any other framing is complex, but a professional can fix it correctly. As far as leveling the floor goes, that can be a DIY project. You’ll have to rip out the old flooring and pour on a leveling agent. Wait for it to cure and then install the new flooring. All of this is much more than a day’s work, so finding an experienced contractor would be the first option.

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