Tricks on leveling / preparing garage floor for concrete ?
- Thread starter Weedwaka
- Start date
1969
Well-known member
Builders level,transit. Can be done with a water hose, much harder though.
nehog
Well-known member
Rotating laser level, a good one, makes the job trivial. With that one person can do the entire job of site prep and forms.
Pour your concrete really runny and it will self level
Laser is the way to go although the guy who poured mine( I set up the forms with clear plastic tube and water) said I had one corner high, guess what now its low
so be careful as transits aren't always money, sometimes they get dropped and don't work correctly anymore
Laser is the way to go although the guy who poured mine( I set up the forms with clear plastic tube and water) said I had one corner high, guess what now its low
so be careful as transits aren't always money, sometimes they get dropped and don't work correctly anymorePour your concrete really runny and it will self level
Laser is the way to go although the guy who poured mine( I set up the forms with clear plastic tube and water) said I had one corner high, guess what now its low
A laser is just as prone to error as an optical level. Know how to check the calibration and you will be OK with either one. I had the concrete guy in for my shop and I asked if I could check his level and it was out. He had no idea how to check it or calibrate it. Most machines have the check proceedure in the manual and how to adjust.
lg
no neat sig line
6768rogues
Banned
I did my 36x48 with a home made water level years ago. We did my son's 42x64 last week with a laser level. Both worked fine.
Shadowdog500
Well-known member
I just had this done by a professional and watched what they did.
First make sure the building is high and dry. To do this you want the building floor level in the building to be higher than the ground around the building. This way you can slope the dirt around the building so the water runs away from the building.
Next they put in at least 4 inches of recycled concrete and tamped it down. This gives he concrete a good base. I had them build up the floor level with recycled concrete instead of dirt, so mine ranges 6 to 9 inches thick, and that stuff is solid.
To set the grade they used a rotating laser level with a detector mounted on a stick, like shown below. The detector beeps solid when it is at the same level as the laser, and it is adjusted up or down on the sick so that it beeps when the bottom of the stick is at the height you want.
Then they dug 2" deep into the recycled concrete 2 foot wide around the perimeter of the building to install insulation. This insulation helps prevent frost heave.
Then they put down a vapor barrier. From what I read, you want to make sure it is good plastic because some of the recycled stuff breaks down after a while. A friend poured a slab without a vapor barrier and has humidity issues.
Then I had them put down a wire mesh. The concrete had fiber and the concrete guy (and everyone else) said it wasn't really needed, but for a few hundred extra I figured I would have both.
Then they put dow the concrete with fiber and finished.
Are you doing the concrete yourself? I watched that too and picked up a few things that I didn't know.
Chris
First make sure the building is high and dry. To do this you want the building floor level in the building to be higher than the ground around the building. This way you can slope the dirt around the building so the water runs away from the building.
Next they put in at least 4 inches of recycled concrete and tamped it down. This gives he concrete a good base. I had them build up the floor level with recycled concrete instead of dirt, so mine ranges 6 to 9 inches thick, and that stuff is solid.
To set the grade they used a rotating laser level with a detector mounted on a stick, like shown below. The detector beeps solid when it is at the same level as the laser, and it is adjusted up or down on the sick so that it beeps when the bottom of the stick is at the height you want.
Then they dug 2" deep into the recycled concrete 2 foot wide around the perimeter of the building to install insulation. This insulation helps prevent frost heave.
Then they put down a vapor barrier. From what I read, you want to make sure it is good plastic because some of the recycled stuff breaks down after a while. A friend poured a slab without a vapor barrier and has humidity issues.
Then I had them put down a wire mesh. The concrete had fiber and the concrete guy (and everyone else) said it wasn't really needed, but for a few hundred extra I figured I would have both.
Then they put dow the concrete with fiber and finished.
Are you doing the concrete yourself? I watched that too and picked up a few things that I didn't know.
Chris
Last edited:
Thanks for the input guys.
My brother was saying to make up a stick and use the floor joists above as a guide. We used the rotating laser transit thing when we did the footings etc but I no longer have access to it. Looking for a po boy way to get the floor level now lol.
My brother was saying to make up a stick and use the floor joists above as a guide. We used the rotating laser transit thing when we did the footings etc but I no longer have access to it. Looking for a po boy way to get the floor level now lol.
The po boy way is to use a water level. Using it right will get you +/- 1/8".
lg
no neat sig line
P.Allan
Well-known member
I checked my laser level ($9) against the highway workers transit and I was different by 1/8" in 70 ft. Good enough for any thing we did building our new shop
If your existing foundation and floor joist were put in correctly, and are still level,
yes you could use a story pole to transfer the level plane to the four corners of
your area that is being prepped. We put an addition on a 40 year old house last
year and found in 28' the existing house floor sloped 2.5" .
yes you could use a story pole to transfer the level plane to the four corners of
your area that is being prepped. We put an addition on a 40 year old house last
year and found in 28' the existing house floor sloped 2.5" .
GarageEnvy
Well-known member
I suppose there are a lot of regional differences and requirements on pad prep. As far as getting it level I'd highly recommend a good quality rotary laser or transit. I tried to DIY this on my 34x53 and I was off by 3/8" when checked by the pros. You haven't mentioned anything about compaction testing. For mine the concrete contractor required the pad to be level within 1" of final grade. After two days of the pros excavating, filling and compacting it was right. Honestly considering the fact that it was 2 days, involved hauling off the old 22x22 slab, took 6 semi's full of fill, was excavated 2' down to get rid of a ton of tree roots from 4 50' trees and was recompacted after every 6" of fill, I'd say the $1,500 was money well spent to have it done professionally. Forms are being set today and they are using a laser. I'm all for saving a buck but that's a big slab to DIY.
nate379
Banned
3/8" in 50ish feet isn't bad at all. I doubt you could even notice that.
That's nothing... like you say, probably never notice that.
Proper pad preparation is important though. I wish the folks that poured the
pad I am working with at the moment had taken a tad more care in their
project.
Take a look at these two pictures and see if you can spot the trouble:
shamrock12
Well-known member
Holy ****, that must've been off by at least a foot! How big is the pad? At least this isn't yours!