![]() When you place a load bearing wall on top of concrete there also needs to be a load bearing footing under the concrete floor to support the new load points. Balloon framed walls need to be tied to the floor joists to keep your structural elements locked together as one. platform framing that is used in new construction these days are not designed with the same structural values. Do not buy the inexpensive lines of their glues as they will not be designed for your application. Glue heavily with a polyurethane-based CONSTRUCTION Glue like Liquid Nails construction glue. Before nailing I would draw the joists together with some 1/4" lag bolts every 2'-3' or as needed. They should be glued and nailed with 4 16d nails vertically at every 12" spaced rows. The new floor joist patch will involve new floor joist for the entire span and should coincide with the exterior wall studs from the balloon framed exterior walls. The area that needs a patch or repair cannot be fixed without providing a new bearing point for the new load distribution. If you want a 2' cantilever then a floor joist needs to be a total length of 8'minimum from bearing point to bearing point. A floor joist can only extend 1/3 of the distance of the total span from beam to the foundation wall. The middle of a span is the weakest location in that floor joist. You cannot make a splice in a floor joist in the middle of its span and expect that to be sufficient. We sistered ~8' of the damage end of the existing joists so that the sistered joist (2x10), with the notch, would rest at the proper height on the sill place. The question is would we better to use a full length (16’) 2x8 as a sister, or an 8’ 2x10 that only sisters the bad end of the joist, the end that would rest on the sill plate? In either case, we want to remove the "added later" beam (shown in the light purple), so that the run from the main beam to the wall is uninterrupted. ![]() A shorter piece of 2x10, 8’ long would also work (we have two of these dry fitted in place). HVAC ductwork, and other things in the way. But, we don’t have room to slide a 16’ 2x10 in place – too many pipes. Our desire is to use 2x10’s, 16’ long that would sister a joist along its entire length, from the main beam to the sill plate. We want to sister the joists with new lumber, 2x10 or 2x8. The blue beam is being used to raise the joists to their proper height. Oh, and some of the joist are split at the sill plate end. We think this beam was added to support the joists which no longer rest on the sill plate. These joists are also supported by a 4”x4” post (used as a beam) at their mid point, which means they are basically a long cantilever. In some places the joists seemed to be short of the sill plate. My son discovered, after removing some insulation, that the joists were no longer resting on the new sill plate. Sometime in the past, the sill plate in this part of the basement was replaced. On the outside wall, they were also notched to sit on the sill plate. They bear on a 10”x10” wood beam that runs down the center of the basement, with a ~1” deep notch cut into the bottom of the joist, and extend to the outside wall. The joists in question are true 2”x10” lumber approximately 16 feet long (for the longest run). The first floor joist rest on the sill plate and were at one time nailed to the studs. The wall studs rest on the sill plate, and extend all the way up to the 2nd story. We have been working on some framing repairs in the basement, and have some questions about the best way to sister some joists. You want the best wood there to carry the shear load.My son recently bought a 100 year old house. Be sure to recheck to make sure deflection is ok.įinally, I suggest that you pick the "best" end of each individual member to at the end of the beam. It is asking a lot of a simply supported beam of any material to perform well with that slenderness. I agree with dcarr82775 that the glue is most important don't cut skimp on that.Īdditionally, the span to depth ratio of the beam is very high, 26.7 (i.e. In principle, this is not much different than coping of a steel beam at the connections. Likewise, since the one foot length of single 2 x 12 at each end is adequate for shear this is not a problem either. IMHO, if the two members are properly bonded over the 23 foot overlap (which should be pretty easy to do considering the length) then the splice in not a problem. ![]() See "Bending Strength of Vertically Glued Laminated Beams with One to Five Plies" at this link: Their conclusion is that for common grades of lumber bonded 2-ply beams perform better than two separate individual members. Department of Agriculture, Forest Products Labs has looked into bending in bonded multiple-member wooden beams.
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