beefing up the joists was the only answer. for blocking, i ran a 2×4 perpendicular to the joists across their bottoms at the center of the span. with the butt end of the 2×4 against the foundation, i worked my way across the floor, plumbing the joists and screwing through the 2×4 into each joist to secure them.
the easiest way to repair a compromised joist is to firmly attach another board of equal or larger size to the questionable joint. this board is called a 'sister board' and the whole process is
4. make an angle cut at the mark that ensures a better joint where the inner end of the new board will butt the existing ledger at the selected joist.
as with the joist size, the building code for your structure will stipulate the proper spacing between floor joists. the code itself is determined by the engineering requirements of a particular building. normally, floor joists are spaced 16 inches apart on center. this means from the center of one upright joist to the center of the next.
step 3 - install the sister joist. you will need two rows of screws at each end of the joist, around 1/4 inch from the top and bottom edges. before you screw these into place, add a layer of construction glue to the sister joist. press it into the pole of the pre-existing wood support. tighten the screws into place with your screwdriver. attach the bottom of the joist to the wall.
step 3: place the plate on the joint. place the plate against the holes that you created in step 2 of this how-to process and take a screwdriver to secure the plate using the appropriate screws. make sure that the screw heads are flush with the joint. this should complete the process of strengthening your wood joint with steel plates.
in this q. and a., david grandpré, p. e., a structural engineer with c. a. pretzer associates inc. in cranston, rhode island, answers a question discussing joints in the layers of a built-up beam. read on and learn more.
decking is installed in a regular pattern so that the joints of alternating courses are aligned. step 4 - remove the damaged joist or joists remove the fasteners from the joist hangers and any that might be attached to a cross beam. you can leave the joist hangers in place if they are undamaged. remove the damaged joist.
in situations when sistering damaged floor joists with lumber of similar dimensions, it can be easy to notch and slide the sister board into place. however, doing this does not fix the slant that the floor has taken since the old joists got damaged. take some extra time and jack the damaged area up so that the new lumber doesn't need to be notched. 3.
if a crack or sag is isolated to one area, the sister joist should extend at least 3 ft. on both sides of the problem area. but its usually best to run the sister joist over the entire span. when the sagging joists are level, apply a generous bead of construction adhesive to the existing joist.
one of the problems with complete removal is the the floor above is nailed to the joists. that's why the preferred and easiest method is sistering to the old joists. if you treat the old joists for termites, clean up as much of the mold as you can and sister on treated joists you should be o.k. without moisture the mold should be little problem. jack
how to sister a floor joist. place two hydraulic floor jacks under the 4-inch-by-4-inch post, and raise the post until it contacts the floor joists. raise the jacks about 1/8 inch more. only raise the jacks about 1/8 inch per day, allowing the house to settle so you avoid cracking drywall and flooring.
building a weatherproof deck that will withstand any climate or condition, including: deck posts, butt joints, dry rot, ledger, cutting, fastening and types of lumber.
wood joints that have been attached with glue or nails over time become loose and need reinforcement. one way to strengthen your wood joints is to use steel plates. plates can be tee plates, angle plates, corner plates or a mending plate for your wood joint. this article will discuss the types
q: how do i repair a deck joist that is starting to rot? a: the easiest way is to repair a joist is to install a sister joist to strengthen the damaged area. use a hammer and chisel to chip away the damaged wood. liberally apply two coats of waterproof sealer over the damaged joist. cut a reinforcing sister joist from lumber that is the same dimension as the damaged joist.
sister refers to attaching an additional framing member alongside an existing member. with roofs, this is done to improve the load value of rafters when installing roof-mount air conditioning
deck joists last longer if you protect them from rot. the same statement applies to all structural framing members in your house, but most of them aren't as exposed to moisture as deck joists. if you nail or screw the decking boards directly to the joists, as many builders do, you create moisture traps between the boards and the joists.
replace deck joists in 6 steps. it is sometimes necessary to replace deck joists that have become time worn or damaged due to exposure to the elements. decks that endure wide ranging seasonal temperature extremes as well as large amounts of precipitation will eventually become susceptible to weathering and decay that even pressure treated lumber
maximum notch depth in the outer third of a joist is one-sixth of the joist depth. limit the length of notches to one-third of the joist depth. no notching in the middle third of a joist. floor truss rules. no notching or boring anywhere joist construction: good planning means less notching wood and boring
sistering a new joist. cling under the house pier and beam i found a joist i do not like one little bit. a few of my joists have some minor termite damage that i plan to repair with bondo, but this one has some heavy damage on the bottom 4 inches for about three or four feet, bad enough that i could probably just rip the bad parts out by hand.
once this has been completed, you can fasten the decking to the joists. sealant for cedar decks. once the deck has been constructed you can prepare it for a sealant. this is vital in prolonging the life of your new deck, and should be done right away. you can choose to stain your deck or use a clear sealant. either way it will be protected and beautiful.
use a hammer and chisel to chip away the damaged wood. liberally apply two coats of waterproof sealer over the damaged joist. cut a reinforcing sister joist from lumber that is the same dimension as the damaged joist. treat all sides of the new joist with the sealer, and face-nail it flush over the old joist with 10d nails or screws every 2 feet.