shimming a header

11 years ago

I'm building a support header for a floor to allow tiling above. My header doesn't contact all the joists since they have a little variation. I need to shim where there are gaps between the header and the joists, but the commercial pine shims look too soft for all the pressure they will see. Anything else better for this application?

Comments (8)

millworkman
11 years ago
I would use metal shims
snoonyb
11 years ago
"they have a little variation."

In order for your header to accomplish it's function it needs to loaded, so forget the shims, load the floor with the tile.
If you shim several, load the floor and a "little variation" occurs in the rest, are you then going to shim again, or remove some of the previously placed shims?
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sombreuil_mongrel
11 years ago
If I was going to the trouble of adding a mid-span beam, I'd be very tempted to break the backs of the joists by cutting them through so the weight is all on the new beam from the get go, much less shimming required.
Casey
bus_driver
11 years ago
"If I was going to the trouble of adding a mid-span beam, I'd be very tempted to break the backs of the joists by cutting them through so the weight is all on the new beam from the get go, much less shimming required.
Casey"

This would not be my choice.

Older joists perhaps were never "dressed" (run through a planer) for smooth surfaces and uniform size. They may vary in size when sawn from the log. In one case, the gap that developed between the top of the some of the joists and the subfloor boards was just a few thousandths of an inch. Coating business cards with Gorilla glue and inserting in the gaps ended the squeaks.
jaansu
Original Author
11 years ago
I found composite shims in the lumber area of HD. This seems to be what is usually used. Perhaps metal would compress even less but these are rated for very high loads.

I'm not sure how loading the floor would cause new spaces to open up. More likely it would cause any existing ones to collapse. But that is exactly what I don't want since it would imply deviation from what seems to be a flat floor at the moment.

I'm probably overengineering this since I am adding 5/8" plywood on the floor anyway and then Ditra before tiling, but the composite shims should keep the joist aligned as they are now.
brickeyee
11 years ago
"I am adding 5/8" plywood on the floor anyway"

That does not reduce deflection by an appreciable amount.
alan_s_thefirst
11 years ago
Incompressible shims are the way to go, those composite ones are probably best, or metal. Don't hammer them in so much that you raise the floor.
jaansu
Original Author
11 years ago
Those composite shims did the trick. I did put them in really snug and since I noticed the next joist/shim interconnection was now loose, backed off a little on it.