Does anyone have any input on how much error you can have when it comes to leveling the forms for a slab? Right now, I have about a half inch height difference in my forms from corner to corner. Is 1/2 inch too much for level? It is 26'X40'. Thanks!
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Slab elevation
- Thread starter Ebuuck
- Start date
pattenp
Well-known member
1/2" isn't going to be the end of the world if it's on the low end towards the door to allow drainage. If it's towards the back then you will end up with water puddles from wet cars. Technically I think 1/8" to 1/4" can be achieved using a quality laser lever.
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Kevin54
MEMBER EMERITUS
If it's just your forms so far, raise them up 1/2".
Falcon67
Well-known member
We were level then due to some mishap in the pour ended up with a 2"+ drop from one corner to the other. Building stands fine, no issues. But it's much better to stay level IMHO.
Cyberbear
Well-known member
All my concrete people claim they can level a slab to within 1/4" of level, but the reality after a rain reveals the truth, I'm lucky to get 3/8" deep puddles. Since some of my projects need a level floor to make fabrication a little easier, the flatter the better, when possible. A bad floor never gets better with time.
Kevin54
MEMBER EMERITUS
All my concrete people claim they can level a slab to within 1/4" of level, but the reality after a rain reveals the truth, I'm lucky to get 3/8" deep puddles. Since some of my projects need a level floor to make fabrication a little easier, the flatter the better, when possible. A bad floor never gets better with time.
I don't care who it is, but basic concrete guys will never get a large slab level to a 1/4" without spending all of their time shooting grade ever few feet. Just the weight of the concrete itself will cause a difference in areas.
If you are depending on the floor to build different projects, you had better get a large blanchard ground table to fixture things up on and not depend on a concrete floor.
ConCretin
Well-known member
Your finishers will probably rely on the forms to establish grade around the perimeter so you really want to get your forms a lot closer to grade than 1/2" - you should be shooting for as close to perfect as the lumber will allow. It shouldn't be that difficult if you have a laser or level.
Getting a flat floor depends on two processes. Screeding determines the overall levelness of the floor (this is where your forms come in) while floating determines the waviness of the surface.
A good floor crew can produce a floor that doesn't show more than a 1/4" under a 10' straightedge without too much difficulty and an 1/8" if they know it's required.
Getting a flat floor depends on two processes. Screeding determines the overall levelness of the floor (this is where your forms come in) while floating determines the waviness of the surface.
A good floor crew can produce a floor that doesn't show more than a 1/4" under a 10' straightedge without too much difficulty and an 1/8" if they know it's required.
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