I did search on this …. honest 🙂
I am HO, but have construction education and worked in roofing contracting for 15 years, but as desk type jockey, so I know how things go together, but not necessarily how to put them together.
Main floor on 2 storey house, expanding kitchen into dining area (have bldg. permit already as load bearing wall is coming out). Floor joists are 2×8 x 16″ oc, 10′-3″ clear span. One end rests on sill plate on outside of 8″ poured concrete and other is on steel beam. Right now it is stripped to subfloor 5/8″ T&G ply. Basement below is unfinished.
1 joist has dropped / sagged 3/4″ and 2 joists either side 3/8″ +/-. I want to level this area and beaf up these joists. The frig will sit on this area and I’m installing a new partion parallel with joists.
My intent is to pull up the sub-floor and replace the lowest joist with 2 new (joist was not nailed to any header or joist over beam i.e. was left loose, and has warped.) The other 2 I intend to sister new 2×8. I think I can get a 10′-7″ joist into the space (existing are 11′-0″) which will give me 3″ bearing on steel beam and 3″ onto a new sill on concrete.
My dilema ….. existing 2×8 are 15 years old and 7 1/4″ …. new joists will be 7 3/8″ – 7 1/2″. Do I persuade the new ones into place with the help of a BFH (sledge hammer) and live with the slight raise until they dry or glue & screw or nail to existing and not rest on bearing and hope glue etc. maintains the finished height I want. Other option is to notch, but wouldn’t that result in a sagged floor again?
Thanks
Replies
you might consider using a LVL for your joist instead. stronger, stiffer but unfortunately more money. i think the actual dimension is 1 3/4" x 7 1/4" which might make installation easier. you could also rip down the piece to your desired width without really compromising the structural integrity. unlike dimensional lumber, LVL's are very stiff and a 1/4" wouldn't be missed much.
good luck
Actually LVL might be a good idea. I was aware of them but was not thinking of them for this application. Thanks, I'll have to look into costs and availability.
scottbr --------
although you didn't specify, I assume that there is an inteior wall over the steel beam preventing you from accessing its full width with the floor joist. if not, then a firemans cut on the new joist for under the mudsill end will give you much greater bearing surfaces; which is the best solution if possible. your new joists should be the same height as the original existing ones. simply ripping them to the correct dimension is all that is required. sister the new joists along side the old; use plenty of construction adhesive along with your mechanical fasteners. don't forget to jack the old joists up to the correct position before making your mechanical attachment.
tealwood
Interior load bearing 6" stud wall is directly over steel beam.
I never thought of firemans cut, I'm assuming you mean cutting ends on an angle, top to bottom, but I don't think I'll get the clearance to get the full length into place.
If I rip them to 7 1/4" (KD wet) will they not shrink in future when they dry to normal house humidity and drop 1/4"?
Edited 3/23/2005 5:40 pm ET by scottbr