Go Back  DoItYourself.com Community Forums > Interior Improvement Center > Framing, Flooring and Sub-Flooring
Reload this Page >

Best way to level a sagging floor - affects 5 joists - sagging 1+ inch

Best way to level a sagging floor - affects 5 joists - sagging 1+ inch


  #1  
Old 02-07-15, 12:11 PM
J
Member
Thread Starter
Join Date: Aug 2014
Location: USA
Posts: 7
Upvotes: 0
Received 0 Upvotes on 0 Posts
Best way to level a sagging floor - affects 5 joists - sagging 1+ inch

Hello everyone,
This site has helped me in the past, so here goes.....

My kitchen/dining room floor is sagging. I can see that it is sagging about 1 inch over a 5-6 foot span. The sag in the joists is halfway between the foundation wall and the support beam in the middle of the basement.

I have 2 bottle jacks as well as 2 adjustable screw columns - that go from floor to ceiling. I also have several 4 x 4 posts 8 feet long. Was thinking of using a 4 x 4 to span the 5-6 sagging joists with screw jacks on each end?

I can access from the basement. After I get the floor raised, I will build a stud wall underneath in the basement to permanently support the joists.

What is the best way to go about raising up the floor - and what to use?
WHat is the best way to determine how much to raise - go up until level - or string line, etc?

With this much sag, I imagine walls will crack?
Is this easy to do, or should I find someone who has done this for a living?

Thanks, Mark
 
  #2  
Old 02-07-15, 01:14 PM
B
Member
Join Date: Oct 2008
Location: New England
Posts: 9,460
Received 47 Upvotes on 43 Posts
Hi Mark,
I recently had to bring my bathroom floor up about the same amount. The house was built wrong with an off center wall over a centered beam in the basement. That meant my jacking would be lifting two floors and it was a lift. I built a 12' triple 2x10 header with 1/2" plywood sandwiched between the layers from alternate ends. Not perfect, but wanted to leave it in place once in position.

I notched the end next to the foundation to set on top of the foundation and wedged a supporting 2x6 below it. At the other end I used a 20 ton bottle jack and progressively jacked it into place. Once in full contact with the joists above it still needed to go up another 1/2". Wow was that a load. Once in place and floor above was level I installed a heavy duty screw jack, not the typical light duty.

It came out perfect and for me was a reasonable DIY, but I have some experience. If things decide to let go you need to be sure they don't go your way. The advantage of jacking up a floor it at worst it will fall back to where it was. But any wood supports can explode if they aren't heavy enough.

IMO, a 4x4 won't be strong enough to achieve that much of a lift and until you start lifting you won't know what else is going to move. Careful you don't lift the ends right off of the center support. It may take time and gravity to bend them back to straight.

Bud

Bud
 
  #3  
Old 02-07-15, 01:54 PM
XSleeper's Avatar
Group Moderator
Join Date: Dec 2004
Posts: 27,061
Received 1,910 Upvotes on 1,716 Posts
Bud is right... a 4x4 is not a structural header. But if you're going to build a wall under the area, it would work as a top plate.

Best way to raise it is with a header and a couple bottle jacks. You don't really need any strings or levels if you are just straightening it, between two points.
 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: