Replacing Subfloor under interior wall

Reply

  #1  
Old 04-08-15, 01:15 PM
B
Member
Thread Starter
Join Date: Apr 2015
Posts: 15
Received 0 Votes on 0 Posts
Replacing Subfloor under interior wall

Hi All,
Looking for a little help on a project I worked on this weekend. The home I just purchased had water damaged under the fridge. The water rotted the subfloor under the fridge and into the bedroom closet floor behind it. The subfloor is a single sheet that goes under the wall from the kitchen to the bedroom closet. This is where my question comes. I cut out both sections for the subfloor and knocked off the rotted pieces that were still connected to the bottom of the wall. When I tried to replace with a single sheet of subfloor, I could not slide it under. The wall has sagged a little towards the corner. The wall runs parallel with the floor joist. I had to cut sections for both sides of the wall. Under the wall I ran 3 2x4s with shims to support the wall. I wanted to see if this is the correct way to do this? I just read another option would be to cut the base plate, slide the subfloor in and then reinstall the base plate. Let me know what you think
Thanks!
Bill


Name:  Floor.jpg
Views: 9397
Size:  20.3 KBName:  Floor 2.jpg
Views: 7372
Size:  21.9 KB
 
  #2  
Old 04-08-15, 01:50 PM
M
Forum Topic Moderator
Join Date: Mar 2005
Location: USA - N.E.Tn
Posts: 47,827
Received 361 Votes on 318 Posts
Welcome to the forums!

I don't know if it's correct or not but I've always just drove in shims or short pieces of plywood to replace the rotten subfloor that was missing under the base plate ... and then replace the sub floor on each side with separate pieces.
 
  #3  
Old 04-08-15, 02:00 PM
B
Member
Thread Starter
Join Date: Apr 2015
Posts: 15
Received 0 Votes on 0 Posts
Thanks Mark, that is essentially what I did. Only place I could not replace is the corner (you can see it in the second picture). I got nervous taking the corner out support wise and wanted to limit the hardwood floor I have to replace. The rot is only about 1/4 inch more in that corner, I think it will be fine. That corner is where I still have a dip.
 
  #4  
Old 04-08-15, 02:14 PM
czizzi's Avatar
Member
Join Date: Jul 2007
Location: USA
Posts: 7,388
Received 14 Votes on 12 Posts
I think you have 2 things working against you. One is that the wall has sagged and you need a lever on a folcrum to lift it back up and hold it there while you replace some wood. Second, is that you are trying to put a piece of plywood in that is at an angle to clear the original boards before it can lay down flat. I would get a long cheater bar or 2x4 and get it under the wall close to the end and lever it up and get a shim in that is higher than needed. Then replace 1/2 of the plywood and place a shim on the new plywood to hold it while you lower the lever out of the way. The new shim will hold it up while you replace the final section. Then use a flat pry bar and a scrap of shim to lift the wall enough to remove the final shim and set the wall back down.

One issue may also be that nails that were driven through the bottom plate may be interfering with the plywood sliding under. Run your hands underneath to make sure all is clear.
 
  #5  
Old 04-08-15, 02:30 PM
czizzi's Avatar
Member
Join Date: Jul 2007
Location: USA
Posts: 7,388
Received 14 Votes on 12 Posts
On further thought, remove the nailing surfaces noted as the 2x4's sistered onto the floor joists. Instead, run 2x8 cross blocking between the two joists under wall. Fasten by nailing through the floor joists with 16d nails. It may necessitate the removal of additional flooring in the closet. Then use the above techniques and slide a section of flooring in from both sides to around 1/2 the distance under the wall. Then ease the wall back down.
 
  #6  
Old 04-08-15, 03:10 PM
B
Member
Thread Starter
Join Date: Apr 2015
Posts: 15
Received 0 Votes on 0 Posts
Thanks for the input czizzi, to be clear you are suggesting to cross brace with 2x8 and shim it until the floor is high enough to slide a piece under? I did cross brace with 2x4s and shimmed until they were tight to support under the wall. I guess I didn’t really think I had any shot at raising the wall like that or even with a lever, because of how tied in it still is.
 
  #7  
Old 04-08-15, 03:29 PM
czizzi's Avatar
Member
Join Date: Jul 2007
Location: USA
Posts: 7,388
Received 14 Votes on 12 Posts
An interior, non-load bearing wall you should be able to move. It is fighting the ceiling joists, but those are under tension to begin with. You will be relieving some of the tension. There is the possiblility you pop through the ceiling, but the wall has to be tied into the ceiling somehow. Be it with cross bracing or a joist directly over the wall. Remove what you have done (sister and cross brace) and stabilize on one side. Get the other side under and transfer the weight shimmed to the other side and then work on the bath side. The wall just need something to sit on. Your goal for the flooring is to be properly supported and fastened down.

The cross bracing will become a part of the floor structure so it needs to be beefed up to at least 2x8 and properly nailed off (not just to nailed). You will be amazed at what you can do with a little leverage and a 6 foot 2x4. Get the leading edge under the wall and push down, little effort will be needed to lift that particular wall.
 
  #8  
Old 04-14-15, 10:32 AM
B
Member
Thread Starter
Join Date: Apr 2015
Posts: 15
Received 0 Votes on 0 Posts
Thanks for the advice, I was able to use a 8ft 2x4 to pry up the wall and slide a new 3/4inch subfloor piece underneath! As far as the subfloor patch is it important to get an exact fit? It was difficult to get in the exact fit, but it is very close and is supported and tight with no flex. I will be installing hardwood over top. I ran into the same situation with moving a heat vent that was in the kitchen. I boxed it out from underneath and cut a piece to fit the vent hole, but it is not perfect fit. let me know if you think I will run into issues with the hardwood install

Thanks
 
 

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