broken floor joist

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Forum topic by Coble posted 03-03-2010 02:10 AM 3566 views 0 times favorited 6 replies Add to Favorites Watch
View Coble's profile


76 posts in 3111 days

03-03-2010 02:10 AM

A tree fell on my shed over the weekend, and pretty much took out half my shed. It broke three floor joist “in half”, its not cracked or split, its in two pieces. I was wondering instead of replaceing the whole joist, if it is possible fixing it by nailing another 2×6 about a foot back from where it cracked and running it the rest of the way. The shed is just for storage, but I still want the fix to last. If ya have any other suggestions, feel free to tell me. Thanks

6 replies so far

View JAGWAH's profile


929 posts in 3109 days

#1 posted 03-03-2010 02:18 AM

Depending on things like span and load use you may be ok. You may also need to bypass the break 2 feet either way and ideally screw together with a good quality deck or truss screw. You could also need to splint both sides using construction adhesive and through bolts.

Depending on height above soil you may benefit fro a couple of blocks and a beam under your splices as well.
lots of good reasons for any of these to be needed.

-- ~Just A Guy With A Hammer~

View John Ormsby's profile

John Ormsby

1288 posts in 3762 days

#2 posted 03-03-2010 02:30 AM

If you can, cut a hole on the end next to the broken joist and slip in new ones fro the outside next to the broken ones. You can then patch the holes you made and paint them. It is always best to replace the joist entirely. I know it hurts to make these types of repairs but it is best.

-- Oldworld, Fair Oaks, Ca

View reggiek's profile


2240 posts in 3295 days

#3 posted 03-03-2010 03:34 AM

It is always better to replace a broken joist.

Bridging could be used to support the joist – using offset pieces between the joists on either side or by resting a cross piece or a pier/post on the ground and offsetting the two halves of the broken joist. If that is not possible, then a splice made by attaching a splicing board (attach as far back from the break on either side that is possible). You could also use steel or metal to splice for more strength. Splices will almost always sag…and they will never be truly plumb…but on a shed it would probably not make too much difference.

-- Woodworking.....My small slice of heaven!

View davidpettinger's profile


661 posts in 3225 days

#4 posted 03-03-2010 04:34 AM

The technique is called sistering. Cut another floor joist 1” shorter than the overall length of the original. Run it in flat, between the joist space. Stand the joist upward, placing the highest edge against the floor and old joist. Then use a habd sledge and a block of wood to drive the bottom in until it goes vertical. After that, just nail the new to the old. Framing air nailer works real good for this. Also, once you’ve sistered up the old joists, you will have actually strengthened that area more than before, kind of like when you install a header over an opening.

-- Methods are many,Principles are few.Methods change often,Principles never do.

View Gofor's profile


470 posts in 3812 days

#5 posted 03-03-2010 06:15 AM

1 foot is not enough unless that gets you to the band edge.

If it is a long run, you can sister it in by going at least 8 times the joist width (i.e for a 2×6 you want a “sister” that is at least 4 foot long + the length of the break if it went diagonal). Ideally it would be centered on the break, but if you run into the band edge at less than that, still go the full 4 foot. Use Liquid nails (Industrial adhesive for treated lumber if that is what it is, otherwise General Purpose grade, whatever brand) on the bond face and spike it in after jacking it (or wedging as stated above) straight. 3” nails from both sides, staggered, about 8” apart on each side about 1” from top and bottom. (that will give about 4” apart for each nail).


-- Go

View Coble's profile


76 posts in 3111 days

#6 posted 03-05-2010 03:55 AM

thanks so very much guys.

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