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Cracked roof rafter repair

I live near Boston and there is a lot of heavy, wet snow on my roof - I recently went up into the attic to inspect and sure enough I saw cracks 12-18" long in 3 rafters emanating from the corner of the heelcut where they bear on the top plate, parallel to the rafters. The rafters are REAL 2x6's at 24" c/c (i.e. old framing, not newer nominal stuff) - this house was built at the turn of the last century. My idea was, instead of sistering them, to first lay flat 2x10's over the ceiling joists and screw them into place, then use vertical lengths of 2x10 as "wedges" to try to permanently "jack" the rafters back up and close the cracks - I would either toe-nail the bases of the "jacks" to the flat boards or use joist hangers to hold them in place, and nail or screw the sloped tops of the "jacks" to the underside of the sloped / cracked rafters. The way I see it, this would both prop up the damaged rafters and prevent them from cracking any further. Any comments or suggestions on this course of action? Any help would be appreciated! I am trying to attach a photo but apparently the max. JPG attachment is 100KB!!!

Timothy Miller
Re: Cracked roof rafter repair

Howdy sister in new rafters and use pl premium and lots of fasteners. F 24" on center is a big spread for 2 by 6". i would sister both sides of the damaged rafters and not just the cracked ones but the ones that have a heavy snow load. Note framing on its side offers very little support-1&1/2" verses 9.5" turned upright.

Re: Cracked roof rafter repair

i understand what you're trying to do but the problem is....what are you using for support under your new knee wall? the vertical columns (2x4's) that you're going to use to jack or support the rafters can't be just propped up on the attic floor, you might be right in the middle of a bedroom ceiling span that can not handle that type of weight. i live just outside boston too and this amount of snow is insane. all i've been doing for the last week is emergency call after emergency call. i've been up on probably 15-20 roofs in the past 4-5 days and the weight of the snow and water/slush below the white snow and above the roof is astounding. you can do what you're planning on but the MOST IMPORTANT thing to do is to make sure that whatever you're using for base support is properly framed to support this huge amount of weight.

Timothy Miller
Re: Cracked roof rafter repair

Howdy first emergency temp shoring of the damaged area -place a temp wall perpendicular to the cracked rafters to bear the loading of the roof.

The rafters sit on an outside wall top plate or a knee wall and at the top of the roof a ridge beam or do they simply bear on the opposite rafter? sistering the rafters would be to support the new ones just like the currant ones.
However it may be substantial damages and you local codes may require you to replace the not up to code roof framing.... Have you considered contacting your homeowners insurace to present a snow load damage claim to your roof? If snow load damage then you have likely coverage to repair or replace the damaged area and also 10% of policy limits for mandated code improvements.
Temp emergency repairs are also covered damages. Gret time to contact your insureer....

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