SIstering joists questions

[Todd.Brock]

Hey all,

Front door leaked for years apparently on previous owner. He covered it up with duct tape, caulk and PT lumber.


This area is behind the concrete steps under the front door. Needless to say- access is restricted! I regraded the front yard, replaced the front door and caulked everything. It's dry and has stayed dry. I am getting ready to put in hardwood floors on the first floor and need to address this. I had thought about a temp steel column by the foundation, but the sill plate is non PT 2x4 and rotten.

My thoughts are this
1. Go to middle of next joist cavity and cut/ replace sill plate with 2x4 PT and then mending plates over the joint and then powder actuated nails to tie into foundation

2. Replacing double 2x10 joists is difficult at best. I will be pulling upstairs carpet to put in flooring, but these joists run under door ways and a wall. Re attaching the Subfloor under these walls and doorways will be impossible without pulling drywall upstairs. Electrical can be pulled and then rerouted but that's the easy part.
3. Current line of thought is to sister in 2x10 as far back as I can back to the stairs which is about 6.5 ft from the foundation on the outside of the double joist. I will have to reroute the electrical going through by the foundation into junction boxes and then extend into another jbox b/c I can't pull the wire down. It is for the front porch lights and brown wire is for doorbell.

Questions- will 6.5 to 7 feet of sistered joists be sufficient with carriage bolts and glue or Should I run one side all the way back to the support beam (about 12 ft) and then run the short side as far as I can, lag and glue and then put a support column under that section? That seems like a lot of work, but doable vs pulling the joists for replacement.

Some pics for clarity/confusion.

 

[sands35]

Since you are going to be messing with the house structure, you really need to talk to your inspector. Perhaps they can provide advice on what to do as well. You may want to talk to a builder as well.

Can you put in a post under the top of the stairs? Then you may only need to replace the sistered joint back to there.

It also looks like the rim joist is rotten? Unfortunately, that can only be replaced from the outside.

The sill plate can be replaced by jacking up the floor joists 1/8" or so. You can rent bottle jacks for that. Since the weight of the house holds it down, I don't think it will need to be attacked to the basement wall. There should be bolts embedded in the concrete for that anyway. (check with AHJ on that one too)

 

[finn]

Jack up the floor joists, cut out the sill and replace it with PT. Then sister the floor joists. You only have to go back a foot or two.

The rim joist has to be replaced from the outside, but it will have a trim board covering it (at least mine did), which is also rotted. You will have to loosen the siding at the bottom for access. Add flashing to avoid a repeat failure.

I did 2 doors and a patio door on my old house over a couple year period.

The first one takes a while, but you can bang out the second and third in a few hours each on a saturday.

The root cause is poor, or no flashing between the stoop and the rim joist.

 

[Todd.Brock]

Thanks for the feedback! It occurred to me this afternoon that I had a structural engineer look at something in the basement and do a report. I shot him an email and he was open to looking at it. He said about the same that sistered only needs to go back a short distance.

The rim joist looks like a 1x10 pine shelf board.. The black is actually a thick plastic mesh that goes behind the bricks. Problem with replacing the rim joist is I would have to tear out a 4x3 concrete porch and then repair and then repour. So I just caulk the steps really well.

 

[bzinsky]

what he said

I'd go 3-4 ft though just so you have more room for screws. When you jack that up and sister it, it's going to create a situation where all the weight is on the sisters and the beam isn't even touching the sill. That's why the repair failed in the photo you have. A couple nails/screws isn't going to hold that beam up.

Do it on both sides.

Sisters need clamping pressure. If you have a home depot near you I would use these exact screws. I would use about 10 on each side. Or even better would be some beefy nuts and bolts through all 6 inches. (will not be easy to drill holes for bolts) You need clamping pressure, which you get from fat heads.
http://www.homedepot.com/p/Simpson-...al-Wood-Screws-25-Pack-SDS25300-R25/203302236

 

[bzinsky]

to be honest if it was my house, I would probably just jack it up and stuff an 8x8 steel plate in there as a spacer just because I wouldn't want to move the electrical. It's tough to get it at the right height with a spacer though.

 

[nadogail]

I think I would notch the supplemental joists to clear the existing wires.

I am neither a carpenter or an engineer. My advice is guaranteed to be worth exactly what you pay for it.

 

[Leaflessshadetree]

Jack it up. Cut the rotted portion of the sill plate out (far enough to get into the neighboring joist spaces). Toe-nail it to the joists.
Your sistered joist pieces can be notched to go over the wires if there isn't a junction box that is convenient.

 

[rsanter]

Jack it up and replace the cill plate. Best way to do it.
It's a bunch of work but not as hard as it may seem
Replace with pressure treated

Bob

 

[Todd.Brock]

Tore into it last night and dang it's a rotten SOB.... I am going to jack up the joist to the right and go a little farther with the sill plate. I found some places where it seems soft. It's a mess! More to come....

 

[The Cobbler]

I have some ideas on how I would fix it, but in reality you might want ti think of getting an engineer to spec what to do. covers your bottom end when you go to sell