best way to correct swollen LVL .. floor lifted
So lets see if I can explain this correctly.
Building the workshop … taking me forever.
I have an 8 ft opening in a wall.
Used a triple 16″ deep LVL on the top … then a double sill … floor joist (rim board on the edge) … the 3/4 advantech …
I am planning on a double plate on the floor edge and then the roof trusses will sit on this.
Problem, the LVL’s have swelled … say 3/8 – 1/2″ /// lifted the double plate off the two studs on each side of the LVL.
So … two ways to repair …..
1) draw a line .. cut the LVL (would need to cut with a circular saw from both sides they a reciprocating saw to reach all the way through).
With luck the floor (double sill, joist, floor ….) would fall when I get the wood out and the floor would again be flat.
2) I can shave down the top double sill (where the trusses are sitting) … it is not in yet so this would be relatively easy to do.
Yes the floor would have a slight bump there but it is the attic of a workshop so it really would not matter.
Just wanted to get a recommendation on which way to go to fix this.
Thanks ….
Replies
Most likely the increase in size is due to too much moisture. When closed in, the moisture will normalize, and the LVLs should return to nominal dimensions.
https://pacificwoodtech.com/wp-content/uploads/2019/05/E705-Proper-Storage-and-Handling-of-IJoists-and-LVL.pdf
If you cut them, you will have issues when they dry out and return to normal size.
I would be tempted to try this:
Instead of shaving the top of the double sill, plan to install the top member level, placing it on spacers that carry the load from each truss to the joist below. make these spacers out of shaved 2x installed parallel to the truss, and plan to adjust to fit as the LVLs dry out and the assembly settles down below this elevation.
It sounds a little fussy, but you are talking about four places. since you have access to the floor, it might work out. You will be around to examine and adjust.
Attach the trusses to the upper top plate with clips and screws. Since you expect the shrinkage, and would not securely tie the trusses firmly to the supporting beam, you will have to provide for uplift protection. supplemental X bracing along the truss ends should help. How tall are these ends of the trusses?
The "right" thing to do would be to temporarily support the floor and replace the LVL beams with dry ones.
I agree on the right way but this is a workshop ... a triple 16" is now $45 a foot ... and even if I did nothing, it would probably be OK
I just wanted the roof flat.
This is only an 8 ft opening so way over built with 3 x 16" LVL
I would be much easier to do what you suggest than to cut them.
I don't think they will shrink but ... but they could.
Thanks ... MIke
The document I linked to by the Engineered wood association leads me to expect they will return close to the original dimension as they dry. (see page 6)
You may find you need to re-set nails that were moved by the swelling after the LVL shrinks back to original size.
Thinking a bit more, Instead of "shaving", you could make up some shims out of 2x and put a pair of these sets under each truss (in the raised area where you skip the bottom member of the double plate). Just make sure you end up with continuous bearing area under the truss of enough width.
A rip cut at an angle should be easier than trying to shave down with a planer or belt sander, and get you the adjustment you will need. (while also keeping the top half of your double plate parallel to the floor)
Great thinking ....
I know I am probably being way to particular but I like "trying" to do things right.
Thanks!