How To Shore Up Floor Joists

These days many new floors are framed with i joists a type of engineered lumber that s a fraction of the weight of conventional lumber and capable of spanning greater distances image 6 left.

How to shore up floor joists.

If you build a wall to support joists be sure to place a stud directly and tightly under each joist. Set a hydraulic jack and post under the beam and jack up the joists about 1 8 in. Floor joists and posts support the flooring and damage to them is the most common cause of a sagging floor. The floor above will be stiffest if you place the wall in the middle of the joists.

The sagging floor was the symptom and somewhere under the house there had to be a cause. A day until they re level. Replacing joists costs around 100 to 300 for each new joist. Well after doing the navy seal crawl up under the house we found that the joists that were supporting that floor were not actually attached to the sill plate any longer as seen in the photograph below.

Nailing two 2x4s together will work to span about three joists unless the sag is under a weight bearing wall. Floor joists are usually set either 16 or 24 inches on center. The best choice depends on access to the joists obstructions in the floor system or current remodeling plans. Still if asked to span too great a distance i joists will bounce.

You can shore up floor joists and reduce the bounce in a number of ways but the six methods outlined here represent a mix of common and not so common solutions. Jacking them up too fast may cause cracks in the walls and floors overhead. Joist spacing depends on the width of the floor joists combined with the thickness of the subfloor and the distance to be spanned. By building a wall under joists you divide the span.

One technique or a combination may be your most practical solution. Deteriorating floor joists or posts. The longer the distance a joist spans without support the more it will flex. This type of repair may require a building permit and usually requires extensive.

As a rule the same kinds of methods that take the bounce out.