rotten floor joists

Reply

  #1  
Old 05-20-07, 09:14 AM
rebeljeep's Avatar
Member
Thread Starter
Join Date: Aug 2006
Location: illinois
Posts: 155
Received 0 Votes on 0 Posts
rotten floor joists

I tore off an old deck and noticed that the ends of the floor joists are rotton. They have been decayed by years of water. The rest of the joists are in A-1 condition but the ends are rotted and barely sit on the sill. How can I repair this awfull problem without replacing the whole joist. These old joists run a long ways. Iv'e thought about building another wall in front of the old one and have a new sill plate, then scab peices and have a false sill plate in front... Nevertheless, I have the whole mess supported with floor jacks so it don't bow or cave in.,,,,
 
Sponsored Links
  #2  
Old 05-21-07, 09:10 AM
A
Member
Join Date: Jun 2006
Location: USA
Posts: 110
Received 0 Votes on 0 Posts
If this were my house, I would implement a two-stage fix.
1) Stop any further damage by stabilizing the damaged area ASAP.
2) Determine the extent of any sag, out-of-level condition caused by the damage and decide whether it needs to be addressed as part of the ultimate repair. [E g, if a 20' wall section has sagged 1/2" in the middle and is practically unnoticeable, you may decide the expense of correcting that is not justified, and just proceed with the final repair and leave the sag.]

Be aware that the joist ends transfer weight from two sources, down to the sill.
a) The weight of the floor itself. This includes the joists' own weight, subfloor, flooring, furnishings, occupants, and interior non-loadbearing walls.
b) The weight of the exterior wall and roof. Most of this weight comes down through the exterior wall, and the joists ends act merely as blocking between the base of the wall and the sill. But if the joist ends are rotting, the weight may be crushing them and the wall may be sagging. You can stop any further sag temporarily by inserting blocking between the subfloor and the sill, in between the joist ends.

Your temporary jacks will help with the floor weight, but won't do much to support the exterior wall forces.

Scabbing new joist ends onto the existing framing can work, if done right. I would use pieces not less than 3'-4' long, where possible. You can tack them into position with nails but then use stout [3/8" dia or larger] bolts to fasten to the old joists. Use a staggered bolt pattern, but don't put any bolt nearer to the joist edge than one quarter the joist width. I would probably use constructiion adhesive as well. [No such thing as overkill when it's the house I sleep in.]

Because you are fastening new wood to wood known to have rot, I think I would use pressure-treated lumber to make the scabs. Of course I am assuming you will treat the joist ends with something to arrest the rot.

I assume you are talking about a masonary sill of some kind. If there is a wood sill plate I would examine it carefully for water damage, and replace if necessary. However, if this is necessary it gets much more involved, as you will have to establish temporary supprot for the exterior wall while you R&R the sill plate.

Good luck.
 
  #3  
Old 05-27-07, 11:25 PM
H
Member
Join Date: Jan 2004
Location: United States
Posts: 1,168
Received 0 Votes on 0 Posts
I am in similar situation. thanks for the great answer. I have not examined my sill plate yet. My house is 107 years old but has had multiple additions so not sure how sill plate is in that section yet. the foundation there is poured concrete. If the sill is wood on top of foundation, how is it replaced if it comes to that? I am really p***ed at previous owner that did't put deck on correctly!

Bill
 
  #4  
Old 05-29-07, 08:25 AM
A
Member
Join Date: Jun 2006
Location: USA
Posts: 110
Received 0 Votes on 0 Posts
Essentially you have to temporarily take the weight of the wall off the sill, in order to R&R it. I've seen Tommy Silve on TOH do this a couple of times. It's a fairly heroic undertaking. Usually he fastens a heavy beam along the wall, running lag bolts into the studs. Then he uses jacks and temporary blocking to lift the wall enough to remove the damaged sill section and replace it. Then the structure is lowered back onto the new sill.

I'm in the middle of doing this in my garage, not to replace the sill but rather to replace the cheapa** foundation the PO built it on. [Don't get me started on that situation.]
 
  #5  
Old 05-29-07, 10:19 AM
H
Member
Join Date: Jan 2004
Location: United States
Posts: 1,168
Received 0 Votes on 0 Posts
wish I could see it done. I will have to check if they have episodes online or if I can get it somewhere. Do you know if they have them available anywhere?

I have an unattached building that has a garage, and two rooms. It had gravel floor and was unfinished. my wife had a friend's son finish it. put in floor, drywall, drop ceiling. it is nice now, but still sits on 6x6's-no block or concrete, and the floor joists sit in gravel. I know it is just a matter of time till it goes so I was wondering if there was a way to put foundation under it. something like this may work, but you couldn't do it all at once so you would have sections. don't know if that would be acceptable--but be better than 6x6's!

Bill
 
  #6  
Old 05-29-07, 12:56 PM
A
Member
Join Date: Jun 2006
Location: USA
Posts: 110
Received 0 Votes on 0 Posts
"you couldn't do it all at once so you would have sections. don't know if that would be acceptable"

Indeed, I'm doing my garage in sections simply because I'm doing it on my own. If you were to hire a crew you could lift the whole thing at once I guess.

It's extremely tedious because once I have a wall section supported and raised, I then have to demolish the existing crap foundation and excavate a suitable trench below it to pour a footing. Then I set up forms for a new stemwall, pour the stemwall, and strip off the forms. Footer and stemwall are reinforced with rebar. Not fun at all.

This garage is 25 by 30, and I've got one 30' side and 10' out from each of those two corners done, a total af about 50', and an 8' wide strip of new garage floor poured on that side. Right now I've got 30' of wall [the rest of the back and half of one side] suspended in midair. And I've been stalled for six weeks because of wet weather that has the ground soaked. Thought it might be dry enough to start again this past weekend, and I did manage to at least dig out most of the mud that had washed or slumped into the trench. But it's still just too soft to properly shape the footer trench, and it rained every day, and we're forecast to have another rainy week. I may not make any more progress on this until the summer. Sheesh.
 
  #7  
Old 05-29-07, 01:20 PM
H
Member
Join Date: Jan 2004
Location: United States
Posts: 1,168
Received 0 Votes on 0 Posts
Wow, sounds like you have a big project on your hands. Did you talk to an engineer about doing it it steps? Are you leaving rebar sticking out so that the next pour attaches to the previous? Just a thought. I had structural engineer at my house for an addition recently and he mentioned doing that in area that my old contractor poured foundation wall but another wall needs to go right next to it. At this point he suggested putting some kind of steel drilled into the existing wall to tie the two together. He also said to leave some bent rebar sticking out top of foundation pointing inward to tie to the slab when poured. So how do you support the garage if the ground is so soft and muddy? getting a little off topic now so maybe want to PM me? I am not sure how to do that?

good luck
Bill
 
  #8  
Old 05-29-07, 10:22 PM
A
Member
Join Date: Jun 2006
Location: USA
Posts: 110
Received 0 Votes on 0 Posts
"Did you talk to an engineer about doing it it steps? "

Actually I am an engineer. Not that kind though. It's my [detached] garage, and not a habitable space. So I'll do the job however I please. Nothing could be worse than the state it was in when I started.

'Are you leaving rebar sticking out so that the next pour attaches to the previous?"

On the footer/stemwall joint, yes. On the stemwall/slab, no. Read reasonable arguments both ways, decided not to do it.

"So how do you support the garage if the ground is so soft and muddy? "

Most of the time I've had the opposite problem-dry weather with clay so stiff it's difficult to dig out working in an awkward position underneath the wall. the soil is perfectly acceptable for holding up the structure provided ithe weight is distributed over a properly sized foundation, which was not the case. I dug the trench out when it was dry, then the wet weather stopped me, that's all. My temporary supports are 2' square concrete pads, so far no problem with them sinking down.

To use PM, once you've logged in, there is a link at the top of the page "Private Messages". But i will continue the discussion here unless a mod intervenes, i don't think there is a "foundations" thread.
 
  #9  
Old 05-29-07, 10:46 PM
H
Member
Join Date: Jan 2004
Location: United States
Posts: 1,168
Received 0 Votes on 0 Posts
Since this sounds exactly like what I may need to do in future, I was wondering if you had any digital pics you could send me of this? Some shots of beams attached to wall and then how the beams are supported. How thick are your 2' square pads and how far apart do you place them? Are you supporting wall from inside and outside or just one side?

I hope it doesn't come to this on my sill plate!

If you have some photos, let me know and I will PM you my email address to send them.

thanks
bill
 
  #10  
Old 05-30-07, 06:08 AM
A
Member
Join Date: Jun 2006
Location: USA
Posts: 110
Received 0 Votes on 0 Posts
I'll see about getting some shots of the present setup. Might come in useful when we sell, to show what was done.

On the corners, I just extend the beam out beyond the corner and support it directly

On the end of the beam in the middle of the wall, I put in a short cross beam below it, and the cross beam is supported by temporary piers, one inside and one outside. Of course I have to pierce the sheathing for this cross beam. These holes will have to be repaired, but that's not a problem because my wife dislikes the siding on the garage, so we'll be re-siding anyway.

The 2' pads are 2" thick, I get them at the home center. This would not be thick enough for a permanent support, but work fine for temporary pads. Remember the unimproved garaged structure is nowhere near as heavy as a house would be. [No drywall, no floor, etc]
 
  #11  
Old 05-30-07, 08:33 AM
H
Member
Join Date: Jan 2004
Location: United States
Posts: 1,168
Received 0 Votes on 0 Posts
thanks. I think I have a pretty good visual in my mind now. I guess you could use load tables to calculate the beam size. I guess an LVL wouldn't be good for this -the weight isn't bearing right down on it and probably the lag bolts provide a twisting force on beam and I don't know if LVL really is made for that kind of force? But I don't really know. What are you using for the beam?

Oh yeh, where do you get the forms for the walls? Duh, I guess you could just make them. I was thinking about when they poured my walls using the metal forms and thought where the heck do you get those then thought that you probably just make them from wood.
Bill
 
  #12  
Old 05-30-07, 10:15 AM
A
Member
Join Date: Jun 2006
Location: USA
Posts: 110
Received 0 Votes on 0 Posts
I'm using a double 2x10 16' long.

And yes my forms are homemade of plywood and lumber. My approach to getting forms installed
-level and straight,
-as near exactly vertical as possible,
-lined up correctly under the desired final position of the wall,
-supported sufficiently to prevent a collapse or blowout,
-and with the top of the form at the exact level desired for the top of the finished stemwall [so all I have to do is fill the forms and screed the concrete level with the top of forms]

is kind of involved, and you'd never see a concrete contractor doing it, because it's WAY too labor intensive and time consuming. But so far I've done 50' of stemwall this way, and I'm satisfied with the result.

You could however build the stemwalls up using Concrete Masonary Units [CMUs, often just called cinderblock though in fact cinderblock is only one of a number of different types of CMU]. It would eliminate many of the problems I have had to work through pouring concrete, but then of course I would have had to learn the masons' art of laying CMU level and straight. That wouldn't be a bad thing to know how to do actually.....
 
Reply
Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


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