I am working on a 100 year old Victorian. Several of the floor joists have split.
Due to plumbing and wiring, it is impossible to sister new joists to the old joists.
I was thinking of gluing and nailing two plies of 3/4 inch plywood to the split joists. I am sure that I could slip the 8 ft length into the tight space.
The joists that need to be repaired are about 15 feet long so it would take two lengths of plywood end to end and then a second layer overlapping the joints.
Has anyone else had to deal with this type of situation? Or have an opinion on what I am thinking of doing?
Thanks.
Mike
Replies
Mike,
If the wiring will be in the way of the new joists won't it also be in the way of the ply? What is above? living space, attic floor etc..
The joists are in a heated basement with finished living space above.
The plywood would fit because it would only be 8 ft lenghts. The wiring and plumbing is about 1/3 of the way between the houses primary support beam and the foundation wall.
How much plumbing and wiring are we talking about? Why not just peel it out of the way, do your structural repair correctly with a single length of 2x material, redrill the new and splice the wire and pipe?
I hear you on the "right way" to do it.
Unfortunatly, the plumbing is a real sensitive topic. The plumbing which is in the way is for the heating system which is probably 80 yrs old. It is old cast pipeing not copper. There is a very real posibility of a serious snowball effect if we start messing with those pipes. That is why I am working on an alternative plan.
If you can prop the joists back up to a straight line your solution would probably work. If the joists have a permanent bow in them the best you can do is saw off high spots and shim low spots in joists, after installing plywood.I once tried to straighten 3x5 1/2 joists in a victorian much older than yours ( circa 1845) with plywood nailed and glued. These joists sagged about 1 -1/2" in the center. Wound up removing them and install engineered joists.
mike
beleive it or not, the joists are actually straight. They did not CRACK due to weight, they look like the SPLIT as a result of drying. The joist only support the living space above. They are not really carying any load other than people and furniture.
Mike, go ahead and nail and glue the plywood. It will work fine, you may have to remove any loose splinters if there are any.I would use 10d nails and subfloor adhesive, plenty of nails staggered.Glad to hear the joists are straight.
mike
Mike - I read about a technique (back issue of FHB?) using a metal strap about the length of the joist. It's nailed at the top of one end, run at an angle down to the bottom of the joist in the center of the span, wrapped around and run back up the other side of the joist to the opposite corner, nailed all along its length. Apparently it adds tremendously to the joist's ability to resist deflection, and may compensate for the split.
It sounds like a really elegant solution, especially because you could probably weave it through wires and pipes.
Maybe one of the many experts here could comment on this technique, since I've never actually tried this myself and I'm not a structural engineer.
Bill.
If they ain't sagging, don't fix what ain't broke.....
Those old timbers tended split, but you still have enough as far as Bottom Fibre Stress and Modulus of Elasticity, for the dead/live loads I'm sure. Those timbers are usually very clean(no large through-knots) so probably the only concern I would look at is if the whole timber/joist has full bearing onto/into the sill. They use to mortise them inand half the joist was hanging off the sill/ carring beams. If that looks questionable, I'd concentrate on supporting the bottom edges @ the walls.(angle iron, stud wall built on the flat)
I don't think any of this is a concern tho, its been there 100+years
Could you run lag bolts vertically into the joists? If they haven't sagged, the bolts would pin the joist back together.
Are they cracked or checked? Old joists often have checks, a form of splitting which rarely affectes structural strength.
Take a hard look at the ends of the splits, is the wood inside darked, or does it look fresh?
Is the floor above bouncy?
Tool Donations Sought
I'm matching tool donors to a church mission to Haiti - we're shipping a bus converted to a medical facility in (now it looks like) April and can fill it with clothes, tools and all sorts of stuff needed in that poorest of all countries. A few hand tools or power tools can provide a livelihood for an otherwise destitute family. Please email me if you have tools to donate.
Thanks to Jeff and David and Jim and Rich and Steven and Mark and Jason and Shep and Jen and Mike and Joe and Bill and Ken for their offers!
Several donations have arrived! Thanks and God bless!
Mike
In my circa:1680 house I bought a year and a half ago the walls were sagging big time.
When we removed the exterior shingles along with two dbl windows we could see the huge oak beam above it seriously cracked.
The dopes that obviously installed those dbl windows years ago cut out the studs and didnt replace em' with anything but windows.
The walls above it were braced to the addition I added on and the old timber was cut out and then added three 20'x18" lam beams in its place.
Whewwwwwwwww
Be wall.I mean well
andy
"My life is my practice"