Question on sistering rafters

[rwilner]

Hey guys
I have a cracked 2x6 rafter in my screened in porch.

In the past when I've sistered rafters I've used construction adhesive to bond the sistered rafter to the damaged one, along with bolts.

These rafters are all painted though, in a yellow latex paint.

Do I have to somehow strip the paint before applying the adhesive? It will it be ok?

 

[matt_i]

I would scrape or sand that off for several feet in each direction.

Also nice if you can sister from both sides if it isn't a full length replacement.

 

[Lassen Forge]

Wouldn't hurt, as you want your bond to be wood to wood, and the latex paint will be far weaker a bond to the wood (either wood) than the epoxy would be wood to wood (I've seen latex bonds so weak that they will actually peel off in a decade or so, sometimes less). Depends how hard it is to remove the latex, but if it's possible, then I would.

 

[rwilner]

Question
Does anyone make a construction adhesive design for this situation?

I think the latex may have lead under it which makes this a much more involved project.

How much structural benefit am I giving up if I just bolt it up with no adhesive?


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[The Cobbler]

the longer you make the sistered rafter the less flex there will be, therefore the glue becomes less important. can you run a full lenght rafter ?
I would make it as long as possible and nail accordingly

 

[Shiftless]

the longer you make the sistered rafter the less flex there will be, therefore the glue becomes less important. can you run a full lenght rafter ?
I would make it as long as possible and nail accordingly

to that ^^^^^^^^^

An inspector insisted I sister up a joist in my garage because it had a minor split that had been like that for 30 years. Not only sister it up but put up a new joist end to end resting on the same supports as the old joist. He gave me the choice of either 16 penny nails or rated structural screws in a staggered pattern. Never mentioned glue. Simpson makes some 3 inch long hex drive screws that went in easily when driven with a half inch drill motor. IMHO, way better than driving nails into old Doug fir.

 

[joe_padavano]

Question
Does anyone make a construction adhesive design for this situation?

If you bond to the paint, you are now relying on the strength of the paint adhesion to the wood. This is not a good idea structurally.

 

[larry4406]

to that ^^^^^^^^^

An inspector insisted I sister up a joist in my garage because it had a minor split that had been like that for 30 years. Not only sister it up but put up a new joist end to end resting on the same supports as the old joist. He gave me the choice of either 16 penny nails or rated structural screws in a staggered pattern. Never mentioned glue. Simpson makes some 3 inch long hex drive screws that went in easily when driven with a half inch drill motor. IMHO, way better than driving nails into old Doug fir.

++2!!

 

[rwilner]

Thanks guys. I can make a full length sister so I think I'll just skip the glue.


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[James-W]

I would run the repair the full length if at all possible. I would sister a 2X6 on each side of the damaged 2X6. I would use nails but I would use a nail gun and nail the **** out of it. If you would like to use some glue, go ahead, it won't hurt anything, but I wouldn't bother scraping the paint off first. The nails should be more than capable of holding the whole thing together without any glue.

 

[rlitman]

I would run the repair the full length if at all possible. I would sister a 2X6 on each side of the damaged 2X6. I would use nails but I would use a nail gun and nail the **** out of it. If you would like to use some glue, go ahead, it won't hurt anything, but I wouldn't bother scraping the paint off first. The nails should be more than capable of holding the whole thing together without any glue.

+1

If you have a framing nailer, 50 or so nails (and three minutes) later, and you'll be fine. Just stagger the nail pattern so that it doesn't try to split the wood.

A bolt or screw every other foot or so first to keep things together is a good idea.

Glue won't hurt, no matter what you do with the paint.

 

[bob15]

Construction adhisive wouldn't hurt.

For hardware, I would either carriage bolt them together or use TimberLOK screws.

https://www.fastenmaster.com/products/lok-line/timberlok-heavy-duty-wood-screw.html

 

[Lt1cobra]

Over here (Sweden) there are thin metal beams available that you can 'sister' beams with.
What caused the split? Bad from the start or heavy load?

 

[6768rogues]

I never glue them.

 

[Squashfest81]

This is a screened in porch we are talking about. Just sister in a full length. Sure, add glue if you like. I guess 50 nails to join them. Sister on both sides? That is just rediculous. If you were building new only one 2x6 would be needed. Not 2. Certainly not 3.
Good luck!

 

[rwilner]

I'm gonna do a full length win timber loks. Thanks everyone. Love this forum.


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[PT Doc]

Full length ftw. Layout the screw placements and it will look good.