I’ve been replacing 2×10 x15′ dry rotted first floor joists in the cellar of a Victorian home. I’ve been able to remove 2 rotted joists at once and leave the sub floor unsupported in order to have room to slip in the new joists. The floor above is 2 layers of 1 inch thick soft wood subfloor and a layer of finished 3/4 inch fir, finished floor. Now I’m coming to
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Is there room to build Temp support walls on each side of the beam, allowing you to remove it and slide another in? Do the floor joists overlap enough to allow for one built up beam to be placed beside it?
How much do the ends of the joists overhang the beam? This will help determine if sistering will be effective.
Can u provide a picture?
Hi. Thanks for the response.
This "beam" is parralel with many other joists, only this one is a 4x 10 instead of a 2x10. no other joists rest on it. it is essentially a double joist. it is just that a wall is right above it and it is a 2 story house. I could definately lay a 2x6 flat next to it on one side and support it with 4x4's temorarily to shore it up whlle I slide the new double joists in from the other side.... hopefully the subfloor would have enough "sheer strenght " to with stand this... what do you think:? Hey thanks.
Could you build the new beam and slide it in next to the rotten one, remove the old beam, and bang the new beam over 4" into place? I would still support the side opposite where the new beam is being slid into. When you place a 2" x 6" flat on the ceiling nail another 2" x "6 or greater to it on edge, creating an L. Known as a strong back, this will increase the span between support posts. It's posible that if you can jack your support wall that you could move both the old and new beams at the same time (with a sledge) and that you wouldn't need to have the support absent at any time.
This might be a feasable option, is it a load bearing wall above? How many floors? roof/ cieling?
Dont use a 2x6 flat. double it up and use vertical with lots of columns.
There is no such things as dry rot. Rot needs four things to live: Moisture, Food, Oxgen, and Temperature. If you remove any of the four, you have no rot. It's impractical to remove the food (lumber), or change the temperature (do you want to chill your crawl space to below freezing?), or oxygen (I think you get the picture), so moisture is the winner. Dry rot is a descriptive term, not an actual name: rot that is now dry. It's a good thing that you asked the question, because I was reading your post and thinking "he's going to go to all the hassle of replacing the framing only to continue to let them be subjected to the reason that he's working on the old joists." Your best bet is to put a vapor barrier down. FHB issue #153 had an excellent article on this. If you control the moisture from below and the sides, then you should be set. This is assuming the moisture source is not from above, (i.e. plumbing leak, well used bath about joists with bad floor, etc.). If that's the case, then you need to address that problem first.
Good Luck.
Dry rot spreads by spores and needs the four things Jon Blakemore lists. To stop it, any of the four prereq's need to be eliminated. But the spores remain viable for a long time, waiting for moisture, most likely in this case, to return. One method to eliminate the spores is to encapsulate them with epoxy. Check rotdoctor.com (?) I believe. The epoxy is almost like water and gets brushed on. This is also the first step in the restoration of wood that has been compromised by dry rot. I don't know how well epoxy restoration works for load bearing joists/beams.
Hey, thanks for all your advice. This Breaktime is a great thing.
First time I've used it. I like the idea of freeing the old beam from it's flooring nails with a sawsall and building the new one next to it and banging it and the old beam and the temporary 2x6''s out ot the way all at once... perhaps with some soap on the ceiling to assist the move. thanks to all. Except for W, the lying, cheating, pseudo president. P.S. the cellar is no longer damp so I don't think the rotting will continue...