Levelling a platform

[Sean Plant]

Hi Mark,

I wondered if you have had any experience with lifting platforms that have a wobble in the area you need it to go in the gym, and how you might fix it?

Thanks.

[Mark Rippetoe]

To clarify: the floor is not level, and what do you do to correct this is you have to put the platform there?

[Sean Plant]

The platform is level and part of it covers where two concrete floors meet (the two floors were layed at different times). I think this is what’s causing the wobble.

So that part of the floor isn’t level. I’ve put some slate underneath to bring it level. Hopefully the slate will stay in tact. If not I’ll probably have to screw the platform down to the concrete.

I was just curious to know what you’d do in this situation.

[Mark Rippetoe]

Better to shim the platform, not the floor. This requires carpentry. But depending on the gap, floor rubber would work well.

[Sean Plant]

Thanks. I’d have to go with floor rubber now as I’ve glued down rubber matting over the plywood. I’ll have to check the gap, don’t think it’s too much.

[Sean Plant]

Just checked, it’s about 7mm or 1/4 inch off.

[Mark Rippetoe]

Then you may have to use some Thinset on the floor.

[Sean Plant]

Ok thanks for the help.

[Satch12879]

The slate is going to crush. Get some composite shims, not wood, from Home Depot. Do the high corners and midlines. Surprisingly stable.

Alternatively, you can do what SSC Andrew Jackson did in his garage and cut a series of plywood shims to match the floor slope.

As Rip said; there’s always thin-set.

[VNV]

Lots of good advice on floor prep here:

https://www.johnbridge.com/vbulletin/index.php

As Rip said, thinset. Or perhaps self-leveling compound (SLC)