For instance you may have a dining room floor that end to end is level but between those two points are various sags and dips.
Shoring up floor joists.
The floor above will be stiffest if you place the wall in the middle of the joists.
In some cases pouring floor leveling compound will fix the problem.
To check joists and diagnose the problem a pro must pull up the flooring and the subfloor to see what shape they re in.
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.
By building a wall under joists you divide the span.
The longer the distance a joist spans without support the more it will flex.
By jacking up the ceiling of the basement you.
Nailing two 2x4s together will work to span about three joists unless the sag is under a weight bearing wall.
Whenever anyone walked across the kitchen floor in the home where this old house general contractor tom silva grew up teacups trembled in their saucers and pots and pans rattled on the stove.
For more serious weaknesses you may need to shore up the floor joist structure with a cross beam and lally posts.
The sagging floor was the symptom and somewhere under the house there had to be a cause.
Stretch a string across the floor to evaluate the amount of deflection then use it as a benchmark for improvement when jacking.
Shows raisinge a sagging floor gradually with bottle jacks.
Set a hydraulic jack and post under the beam and jack up the joists about 1 8 in.
Place support of the floor joists with wood studs.
It was nerve racking tom recalls.
Photo by richard howard.
Where these repairs are not sufficient also consider shoring up joists or beams that were cut drilled or notched for pipes wires or ducts.
Deteriorating floor joists posts or beams can be caused by termite infestation water damage or dry rot.
Instead it may be an issue with joists and beams below your floor that require shoring up.
A day until they re level.
Tack a beam under the sagging joists.
Eventually his father a carpenter went down to the basement with tom in tow and reinforced the undersized floor joists.
Your foundation may not be the problem.
Then set new joists same height as existing ones alongside the old.
