Releveling porch joists

[Wayne Whitney]

Hello,

As I've mentioned in previous posts, I'm rebuilding my porch deck. Most of the deck joists are in good condition, except they are pitched slightly wrong. I'm wondering if it would be workable to simply sister on a 2x4 to the side of the existing joists, which are rough

2x6s for the 6' span. I would set the top edge of the 2x4 to the desired pitch, which be anywhere from 0" to 0.5" higher than the top of the existing joists. So the 2x4s would basically just be nailers to accept the porch deck and transfer the load to the existing joists.

Any problem with doing this?

Thanks, Wayne

[avid_hiker]

Me.........would bolt on a 2x6 with the correct pitch to the outside of the existing 2x6. I dont believe a 2x4 could handle the wieght long term.

[spamTHISbrp]

If you nailed frequently, a 2x4 would be plenty but it might tend to 'roll over'.

A 2x6 would be better, and in the end prob. easier to work with.

Think about having a board at the near edge and at the far edge that the new sister joist would be pressewd up against just before nailing. Adjust those end boards once, and you have a jig, and all your joists will match position nicely.

Dave

[BobK207]

Wayne-

How are the exsiting joists attached to the rest of the structure (ends) & are they supported in the middle anywhere?

Sistering is on approach but then you've got the face to face "gap" to catch water, debris

...a 2x4 might be a little small but doing the 2x6 thing is the same as rep-placing all the joists

can the exsiting joists be fiddled with (easily) to get your desired slope? You've got the porch pretty much torn apart, could you just re-set the exsitng joists?

cheers Bob

PS Id' use screws (SS of course) to set the sisters....screws are better than nails in a lot of situations

[dpb]

Other than quite a waste of material and that it just sounds "kludgey" to me, the only real potential problem I would foresee might be that you'll create a water trap between the two pieces that might lead to early (as compared to if it weren't there) failures since it won't dry easily between the two pieces. Could put a cap over them, of course, but that's yet another step in the process...

If the house end were at the proper and same level, I'd probably go to the trouble while I was doing it to make the outer rim the proper level and re-hang them correctly, but that's just my nature -- if I'm going to the effort, how much more effort would it actually be to fix it right?

Alternatively, if it is only a 6-ft run, I _might_ consider shimming the low ones as I have bandsaw and jointer to make the tapered cuts a pretty straightforward operation, but still seems like the coward's way out...

IMO, YMMV, $0.02, etc., etc., etc., .... :)

[avid_hiker]

After reading these replies......I believe I am just a learning dumb blonde. Good advise here.....and please take no notice in my post before. I am no expert carpenter but just a DIY. But thanks people, I am learning something new everyday.

[Joe]

Maybe.

People tend to forget that a load on a sistered joist is transmitted to the mated joist mainly through the nails and only small load component from friction. Therefore, top mounted shims are structurally more sound. If you have a table saw, buy a taper sawing jig ($15 or so) and slice off the needed pieces. Use construction adhesive and tack them in place and secure with new floor boards and ring shank nails or screws as preferred. Doing a dozen joists this way shouldn't take an hour; less if you have help, more if the help brought a six pack. HTH

Joe

[Wayne Whitney]

The 6' span joists are not supported in the middle anywhere. The house end of the 2x6 porch joists bear on the cripple wall top plate, with a slight notch on the bottom. The other end of the porch joists are balloon framed into the outer porch wall.

Hmm, taking a closer look, it appears that I would only need to move (raise) the joists on the house side, they are good on the other side. I believe the connection on the house side is just two toenails into the cripple wall top plate, so it ought to be possible to disassemble that without damaging the joists. Then I can just shim between the joists and the cripple wall top plate.

Thanks for the idea! Now I just have to figure out the stairs. :-)

Cheers, Wayne

[Wayne Whitney]

This is a good point and worth considering. The load on each of my joists is 83.33 lbs/ft (10 lbs/ft dead + 40 lbs/ft live with joists

20" o.c.). I believe the shear value of a single 16d common nail connecting a 2x member to a rough 2x member is over 100 lbs. So one nail per foot connecting the sistered member would be plenty for the gravity load.

Cheers, Wayne