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jdrunbike 09-05-2012 01:15 PM

replace/repair rotten rim joist (with picture)

I need to repair or replace a rotten rim joist on my house and have posted pics below. Assuming I get rid of what caused the rot in the first place, I have three questions about my options to fix the rotten board:

1. Given the board is not completely rotted through (it is rotten up to .5" deep on the exterior side), can it be repaired with penetrating epoxy alone?

2. Perhaps in addition to epoxy, can I also sister another board next to it from the inside (making cut-outs for the sill bolts) to provide additional strength/backup?

3. Do I need to replace the board? If so, I imagine I'll need house jacks and may need to cut-out the higher portion of the concrete patio to gain access...correct? I wouldn't plan on replacing the rim joist myself but would appreciate your opinions to help me be better educated when I get an estimate.

Thank you!

View from outside (note hose bib and cut-out in concrete near pry-bar - the sources of the moisture that caused the rot). The gap between the concrete and side of the house is from where I pulled out a rotten water-table board (2x10 cedar) that was attached to the exterior of the rim joist.

A close-up of the rot from the outside:

Another close-up of rot from outside, this time at a pre-existing hole for an old dryer vent:

Same hole, view from inside crawl space:

View of backside of rim joist from inside crawl space:

notmrjohn 09-05-2012 02:33 PM

I don't think i'd rely on the epoxy, its really for holes and such in otherwise sound wood, and best for non-bearing parts. Drive your notched sister in there. From outside chisel, scrape, dig out every bit of rot all the way to sound wood and a bit past, that raised pad is sure in the way, see what ya got left. Treat the exposed wood with your favorite rot-B-gone.You may be able to make a nice notch to drive and fasten a tite fitting filler in there. Got a multi tool? you mite rip bottom of rim off and out and drive in a filler. You mite take out entire rim. and put in new one,perhaps a two piece, ripped from what would be wider one piece.With old rim out, you may be able to drive sister out into place and another sister behind that, just so they aren't lonely.New table, flashing, caulking and all. I realy, really dont like that raised pad. i don't like any of that pad bein up against the wall. I'd like to chisel it back, well, have somebdy else chisel a trench and line it with some super caulk with a bottom sloped to carry water along it and away.

GBrackins 09-06-2012 07:32 AM

I agree with john.

my only question is if that is a raised concrete sill what are the anchor bolts for????? wood in contact with concrete should be treated because of moisture issues.

allthumbsdiy 09-06-2012 07:32 AM

From my limited experience, look on the rotted surface does not tell the whole story. Grab a flat head screwdriver and firmly scrape off the rotted section until you can find solid wood, then make a determination about using epoxy. But from the look of it, you will need to replace that rotted section.

Based on the rot on your rim (band) joist, your sill plate is most likely rotted too. Buy yourself an awl (looks like an ice pick) and poke around from inside to check the condition. My rotted sill plates looked and felt solid from the inside, but once I started poking around, I discovered the extend of the damage.

To remove a rotted rim joist and sill plate, you will need a reciprocating saw, wood chisels and a hammer.

You also most likely will need to rent a small electric demo hammer to remove at least 2 feet of concrete pad to give you enough room to install a new sill plate/rim joist from the outside.

You can install blocking between joists for temporary support but they will have to rest on the sill plate that might be rotted. This is just a ban-aid solution and you will ultimately have to re-visit it later (taking apart the exterior sheathing, shingles, etc. all again)

After getting several $7,000-$9,000 quotes, I ended up doing it myself.

If you want to read about how I did it, just google "how to replace a rotted rim joist and sill plates".

Good luck

notmrjohn 09-06-2012 11:22 AM

Oh boy! You get to buy a few nifty implements of destruction.:)
Don't need a house jack though, in fact you could wind up cracking walls and opening drywall joints. drive in allthumb's temporary blocking while you do job. Set a temporary sill plate behind bad one and block on it. You could leave all temporary stuff there after you put in real stuuf as a backup, somtimes removing temporary can be almost as hard as removing permanent.
GB, I just now saw that, I did see it B4, but I just now saw it. surely not concrete covered sill? didn't leave enuff bolt forthe sill, said fuhgittaboutit, had apprentice screw bolts for practice? Great long all thread, holding foundation to earth for when law of gravity is repealed?
A very small nit to pick,thumbs, me and all the folks I've worked with use "rim joist" if it runs parallel with floor joists, since it is a joist, "rim band" if perpendicular, makes no diff really, some folks may use exact opposite, just so long as everbudy knows what we're talkin about.
BTW "replace/repair rotten rim joist (with picture)" I don't think you wanta do that. Sure it'll look nice, but....

allthumbsdiy 09-06-2012 01:23 PM


Originally Posted by notmrjohn (Post 1004379)
Oh boy! You get to buy a few nifty implements of destruction.:)
A very small nit to pick,thumbs, me and all the folks I've worked with use "rim joist" if it runs parallel with floor joists, since it is a joist, "rim band" if perpendicular, makes no diff really, some folks may use exact opposite, just so long as everbudy knows what we're talkin about.

BTW "replace/repair rotten rim joist (with picture)" I don't think you wanta do that. Sure it'll look nice, but....

Thanks for clarifying rim joist vs rim band.

Also, would you please send me a PM regarding my last sentence? If that was for me, I don't think I fully understand it. :)

notmrjohn 09-06-2012 04:44 PM

thumbs, my fault, i wasn't very clear (surprize) last sentence should have been directed to OP, concerning "title" of thread. I didn't think it was good idea to replace rotted rim joist with a picture.

I'm not so sure if I clarified anything about rim joist or rim bands, so did a bit of web surfing, seems some folks use term as I did, others make no distinction, some use one some use other, some use them intechangably even in same sentence and i ran across band joist, so call it what you want.

GBrackins 09-06-2012 04:50 PM

but a pitcher could throw the ball a lot harder than a rotten rim joist ...... :laughing:

mae-ling 09-06-2012 08:22 PM

Here we call it all a rim Joist if it on the outside edge.

Don't jack the house.
If there are no joists nailed into it, just cut it out and put new section in. Then sister new on on the inside.
If joists are nailed into it, support them with a temporary beam, cut out the rotted area, nail new one in, reside in a way to stop water from getting at it.
Maybe use blueskin or similar.

notmrjohn 09-08-2012 10:08 AM


Originally Posted by mae-ling (Post 1004709)
reside in a way to stop water from getting at it.

Ah, the English as she is spoke and wrote, he is a funny language.
reside: to replace siding or apply new siding
reside: to live or abide in a place.
So, jd, live and reside in such way so as to not allow water from getting to your residing, residing in such a way may mean major changes in your way of residing.

Oh, GB, "I agree with john." When was the last time you had a mental evaluation?

oodssoo 09-08-2012 10:24 PM

Looks like you may have a multiple cause here.... termite, ground water damage, and pest.

To replace it, the concrete will have to be removed, and then the board will be removed and replaced with new. Followed by the replacement of the concrete - with proper flashing and grade it so water can't get in...

Lastly, pest and termite control would be necessary for the entire house IMO.

jdrunbike 09-12-2012 11:35 PM

Thanks for all of the advice! I've finally gotten a better look at the sill plate after digging out the rest of the rotten table. I'm afraid the sill plate is partially rotted and that it may be partially rotted along the whole 40' wall (the concrete touches the wood along it's whole length).

As for supporting the wall while replacing the wood - will blocking be ok? There aren't any joists nailed to it because it is running parallel to the floor joists - which also makes me think the weight of the whole wall and 2nd floor is resting on it, too...which makes me nervous about putting any temporary blocking farther back from the edge of the wall. Is that really ok?

notmrjohn 09-13-2012 08:37 AM

drive blocking as close to old joist as you can, still leaving working room. Shorter blocking pieces instead of one long one, with gaps between for sawzall blade to clear. You'll still bend some blades I bet. When end of sawzall blade hits something it can knock ya back a step. Take old joist and and plate out and replace in sections. Off set joints in new joist and plate sections. Sister in a backer joist, off set any joints in it with joints in other pieces. Screw two joists together, slow setting construction adhesive between them won't hurt. If new table is not one peice, well, by now you know what to do about joints.

oodssoo 09-13-2012 12:05 PM

One thing to add here is to check with local code department. The last time I checked, it's against code having concrete next to wood like that we see in the photo you've provided.... Further, I think if you install flashing to separate the two you should be fine... worth looking into IMO.

allthumbsdiy 09-13-2012 01:57 PM

Just out of curiosity, can you re-take your firs picture from far away?

Also, I noticed a section of the subfloor that has been cut out as well as what looks like a joist that has been cut. Can you also pull back and re-take that picture?

I am visual kind of guy so I took what notmrjohn and said and drew a simple picture. I took the liberty of:

1. Doubling up the blocking to increase the support surface area
2. Added joist hangers to minimize the risk of twisting.
3. For added vertical support, added in a beam and floor jacks.

What do you guys think?

BTW, I am *not* an engineer nor do I have professional experience! This project may also be dangerous so when in doubt, call in a professional.

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