24 thoughts on “Sistering broken rafter in attic for roof repair June 2013

  1. morgando2

    I would of squirt as much glue in and all along that sister and in the crack. While the bolts are loose then tighten. Its cool when the glue ooses out. Your bolt method is good but the amount of wood removed when drilling that many holes the glue is a good mix.

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  2. Darwin Sango

    Although what you did is probably sufficient and everyone has different ways of doing things that aren't necessarily wrong, here's how we would do this one. Get a few 6" truss screws and construction adhesive. Put construction adhesive in crack. Draw the board back together with the 6" truss screws. Plate both sides with the same size board as your broken board, putting construction adhesive between new boards and the old one, and then use truss screws long enough to go through the 1st new board, the old board, and about an inch into the other new board, putting truss screws on both sides. One every 12 inches should be plenty. It's easy, doesn't remove wood and uses the whole surface of the wood, rather than just bolts to distribute weight. We do a lot of lam beams and such too, and think about how strong lam beams are. It's not a true lam beam, but it's easy to do and very strong.

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  3. jjthefed

    I prefer 5/16 or 3/8 bolts on 2×4 sister boards. I drill the holes to the bolt diameter. Bolts tap through the holes with a lite hammer tap with no play. I have used this method on a sagging covered patio (10'x25' decking) roof after I had to jack is up to get it level. Some tool cut the rafters too short so they notched in new ones. 13 years later still no roof sag. I had a home inspector and a construction expert both look at it and both gave me the same recommendation to fix it. Jack the roof level. Install sister boards with screws or bolts. Overlap the ends of the sagging connections by 6" to 1'.

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  4. Joseph Böhme

    Should have used 3/16 steel fitch between the two or(2) outside 2 x 8s  onto this wimpy broken 2×6.   Could have used glue and less bolts. Could have placed washers between sister pieces and that compression would do a better lock of course by taping washers in place after your 1 side pilot holes are done.  Also bolts of this side should be @ 4-5 min. inches away from each other.
    Lastly there is such a thing as square plates rather than just thin fender washers.

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  5. Shawn Ross

    I believe the proper way to fix a cracked rafter is to pull the fascia, pull the soffit and slide a new 2 by up to the ridge and nail it on. Also, one might be inclined to add a gusset with webbing to the ceiling joist, maybe?

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  6. Anderson Hicklen

    Would this same concept work on a portion of wood that has water damage? I was thinking connect a new piece on the side where the wood is still good. The roof has been replaced and the leak is no longer there. Thanks!

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  7. Sandra Sanchez-Rolon

    I have this same split but in the 1st ceiling and 2nd floor, I have a split level 100+ year home… contractor quickly covered with drywall, what is the suggested repair, I'm open to removing the drywall to make it right… the large split is right above my grandson room who does jump in his room ..

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  8. danigomez7

    Hi there. I have a split (about 10" long) on a hip rafter, with jacks attaching to it every 24" or so. Will this solution still work but with smaller boards for clamping? Your advise is greatly appreciated. Thank you!

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  9. wangbungal

    I dont get it what exactly your doing, correct me if im wrong, what you just did exactly was to add a dead load on that crack 2×6. The reason i said that is you attach that new 2×6 with no counter loads at both ends basically floating, well the other tip is touching, so if you have a good load of snow in your roof or someone walking there, that cracked 2×6 will still continue and your bolts will be subjected to shearing, if anything i will extend that 2×6 up to the ridge, and bird mouth the other end so it would sit at the wall plate, then bolt it just saying,

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  10. Tjfreak

    I think I would have sandwiched it,used adhesive,deck screws & focus on stopping the split from furthering & make sure the split isn't due to overheating..if you see sap droplets everywhere, it might be an indicator of poor ventilation.

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  11. Chad Cosgrove

    Man you talk all scientific but while you use the words preload, and shear force and all this other riff raff about structural integrity.. Your 1/4 inch zinc plated shoulderless non grade 8 bolts aren't protecting anything with structural integrity. The way you fix that problem is remove the soffit and facia and slide a new rafter in place next to it to "sister" it with another bird mouth cut and nail it. That is a rig and its doing nothing. If the joists are spread correctly on center that one cracked board isn't nothing. It was a bad piece of lumber. For something to crack like that a tree would have to fall on it with force. That crack will still run. If any force is applied to the roof in that spot you all threaded zinc bolts will shear.

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