Leveling A Concrete Garage Slab - Construction - Contractor Talk

Leveling A Concrete Garage Slab

 
Thread Tools Search this Thread Display Modes
Old 08-11-2019, 05:53 PM   #1
Designer/Contractor
 
Rio's Avatar
 
Trade: General Contractor
Join Date: Oct 2009
Location: San Diego city/County, Cali
Posts: 3,196
Rewards Points: 2,372

Leveling A Concrete Garage Slab


We are involved with a project and part of what we're doing is going to require the existing garage slab to be made level. It is currently sloped .25:12 towards the big door. It has a stem wall so it's already formed on the perimeter.

We are thinking of using pumped concrete to about 2" and stopping it there and then using a self leveling underlayment of some sort from there, planning on using concrete glue for the top of the slab for that part.

If we go from 0" to 2" thick it will be about 15-17 cu. ft.. We're thinking of using something like SikaLevel, have used Sika products before with good results but wanted to see if anyone has another product that is better and to go over pros and cons of what the plan is.

It's in San Diego city so it's very temperate. The space will be conditioned but even if it wasn't there is no freeze/thaw cycle to be concerned with, the highs rarely get above 90 and never get to freezing, it's usually around 70 degrees.

Thanks for reviewing and comments!
Rio is offline  

Warning: The topics covered on this site include activities in which there exists the potential for serious injury or death. ContractorTalk.com DOES NOT guarantee the accuracy or completeness of any information contained on this site. Always use proper safety precaution and reference reliable outside sources before attempting any construction or remodeling task!

   

Advertisement

 

Old 08-11-2019, 06:42 PM   #2
Pro
 
Fouthgeneration's Avatar
 
Trade: Masonry
Join Date: Jan 2014
Location: Middle
Posts: 2,431
Rewards Points: 8,691

Re: Leveling A Concrete Garage Slab


Gyp crete/ fireproofing, contractor, add some Portland for a little more strength?

Al the wood multistory apartments use the G-Crete ask a fire floor/noise barrier, every other floor vertically, two inches + over the 3/4" OSD T & G....

Advertisement

__________________
I might be an Idiot, but I know things that You don't: Please wait till after you get my know-how to insult me....
Fouthgeneration is offline  
The Following User Says Thank You to Fouthgeneration For This Useful Post:
Rio (08-12-2019)
Old 08-11-2019, 11:15 PM   #3
Eater of sins.
 
ScipioAfricanus's Avatar
 
Trade: Designer/Drafter/General Contractor(again)
Join Date: Sep 2008
Location: Orange County, CA.
Posts: 4,058
Rewards Points: 1,956

Re: Leveling A Concrete Garage Slab


HI Rio, forget the self-leveler, just go with pea gravel in the mix and really tamp it so a a thick layer of cream comes to the top.

They may want 6 mil. visqueen on the existing garage slab as there was probably no VB in the initial pour for the garage slab. It will dry slow but strong.

It will have to be about 1" thick minimum though.

Andy.
ScipioAfricanus is offline  
The Following 2 Users Say Thank You to ScipioAfricanus For This Useful Post:
Dirtywhiteboy (08-12-2019), Rio (08-12-2019)
Sponsored Links
Advertisement
 
Old 08-12-2019, 12:11 PM   #4
Pro
 
dave_dj1's Avatar
 
Trade: general contractor
Join Date: Mar 2010
Location: Upsate Ny/Vt border
Posts: 1,002
Rewards Points: 1,118

Re: Leveling A Concrete Garage Slab


Mud jack it?
Or use spray foam to jack it up on the low end.
dave_dj1 is offline  
The Following User Says Thank You to dave_dj1 For This Useful Post:
Rio (08-12-2019)
Old 08-12-2019, 02:10 PM   #5
Designer/Contractor
 
Rio's Avatar
 
Trade: General Contractor
Join Date: Oct 2009
Location: San Diego city/County, Cali
Posts: 3,196
Rewards Points: 2,372

Re: Leveling A Concrete Garage Slab


Hi Scipio, it's going to be 6 sack pea gravel so 3,000 psi, guess we could go less than 2" but I'm skeptical about long term stability at 1" and would like to take it down to about 1/4" or so for threshold purposes; did think about a vapor barrier and like the idea but I think that once it's getting down to the thin end it would be accentuating the cold joint, they'll just have to go with tile on the floor and area rugs.

Regarding mudjacking it's a monolithic slab on grade with a continuous footing so that's not an option.

Contractor wants to use a product called Levellite, never heard of it, need to check it out.............
Rio is offline  
Old 08-12-2019, 11:19 PM   #6
GC/carpenter
 
Calidecks's Avatar
 
Trade: Decking, Railing, Carpenter/General Contractor
Join Date: Nov 2011
Location: Anaheim Hills, California (OC)
Posts: 37,309
Rewards Points: 21,258

Re: Leveling A Concrete Garage Slab


I've done this with great success. Did it like Andy said. We made the garage into a room and built them another garage. We used 6 mil as well. It came out great. However I think our thinnest area was 3" thick. I'd have no problem doing it again in a heartbeat. Remember it's not really structural it's just a fill so to speak.

We pushed around all kinds of ideas. Those in hindsight seemed to be Overthinking it. Imo


Mike.
_______________
Calidecks is online now  
Old 08-13-2019, 12:35 AM   #7
Designer/Contractor
 
Rio's Avatar
 
Trade: General Contractor
Join Date: Oct 2009
Location: San Diego city/County, Cali
Posts: 3,196
Rewards Points: 2,372

Re: Leveling A Concrete Garage Slab


Yeah, I like Andy's suggestions, good advice all the way around, especially the tamping till the cream rises and the vapor barrier; thinking now maybe 6 mil up to 2" and then nothing from there on, the half loaf is better than none theory.

I was reading up on the levelLite and it looks like it's good stuff, has a bunch of ASTM compliance statements on the cut sheets, I'm attaching them in case anyone wants to take a gander.
Attached Files
File Type: pdf TDS-107.pdf (94.4 KB, 5 views)
Rio is offline  
The Following User Says Thank You to Rio For This Useful Post:
Calidecks (08-13-2019)
Old 08-28-2019, 12:23 PM   #8
Registered User
 
rounde683's Avatar
 
Trade: Electrician
Join Date: Aug 2019
Location: Seattle
Posts: 16
Rewards Points: 32

Re: Leveling A Concrete Garage Slab


Self leveling compound. It's pricey per bag but super easy to do yourself.
__________________
Removed by staff
rounde683 is offline  
Old 09-11-2019, 12:01 PM   #9
Designer/Contractor
 
Rio's Avatar
 
Trade: General Contractor
Join Date: Oct 2009
Location: San Diego city/County, Cali
Posts: 3,196
Rewards Points: 2,372

Re: Leveling A Concrete Garage Slab


Now we're thinking of taking the 6 sack(3,000 psi) pea gravel pumped concrete to as thin as we can and still have it adhere to the sloped slab below it. I'm not sure how thin it can go without having delamination issues. We're thinking of putting concrete glue after the 2" thickness and going to about 1". Is this going to come back and bite us on the butt is the question.

The other issue is for the vapor barrier. We found a product called Bone Dry, talked to their technical department and it sounds good. They don't have any independent lab testing on it which can be a problem in San Diego. The building department is very picky on products, ask for ICC or UL or similar reviews all the time. Here's the link to their site if anyone wants to take a gander at it. The techie said we should use the Bone Dry Original.

https://www.bonedryproducts.com/
Rio is offline  
Old 09-12-2019, 01:28 AM   #10
Pro
 
Fouthgeneration's Avatar
 
Trade: Masonry
Join Date: Jan 2014
Location: Middle
Posts: 2,431
Rewards Points: 8,691

Re: Leveling A Concrete Garage Slab


3000KPSI concrete will erode away with a stiff broom....

either top dress with Portland powder for broom proof surface, or just man up with > 4000PSI mix....

I'd have some sand mix + bonding agent ready to go as soon as the truck is gone,
to infill at the feathered edges, the pearock mix will be a nightmare anywhere the rock is bigger then the infill is deep.

No joy on Gypt- Crete subs?
__________________
I might be an Idiot, but I know things that You don't: Please wait till after you get my know-how to insult me....
Fouthgeneration is offline  
Old 09-12-2019, 07:36 AM   #11
Designer/Contractor
 
Rio's Avatar
 
Trade: General Contractor
Join Date: Oct 2009
Location: San Diego city/County, Cali
Posts: 3,196
Rewards Points: 2,372

Re: Leveling A Concrete Garage Slab


Quote:
Originally Posted by Fouthgeneration View Post
3000KPSI concrete will erode away with a stiff broom....

either top dress with Portland powder for broom proof surface, or just man up with > 4000PSI mix....

I'd have some sand mix + bonding agent ready to go as soon as the truck is gone,
to infill at the feathered edges, the pearock mix will be a nightmare anywhere the rock is bigger then the infill is deep.

No joy on Gypt- Crete subs?
Thanks for the input 4G, appreciate it. I do disagree about the 3,000 psi concrete being eroded with a stiff broom, unless it's diamond tipped, as the normal minimum psi for concrete slabs is 2,500 psi and they seem to hold up just fine. Actually we don't have an option to go with 2500 as the ready mix company only does 6 sack with pea gravel. It'll be plenty strong in that respect.

My only real concern is how much is a bare minimum for a concrete slab to go over an existing concrete slab. I'm thinking that with concrete glue to help it bond 1" out to work. Like Andy/Scipio had mentioned at the top of the thread, tamp the heck out of it to bring up the cream and to settle the rocks and one would think it would be okay. Having said that we've always done a minimum of 4" and I don't want to find out that at 1" it's going to have bonding issues or delaminate from the slab below. The pea gravel is about 3/8" so 1" should be plenty thick, shouldn't be a problem catching rock when troweling.

Regarding using gypcrete the project is on a budget and we're already getting extras on it due to the city, don't want to incur more if possible.
Rio is offline  
Old 09-12-2019, 05:38 PM   #12
Pro
 
Fouthgeneration's Avatar
 
Trade: Masonry
Join Date: Jan 2014
Location: Middle
Posts: 2,431
Rewards Points: 8,691

Re: Leveling A Concrete Garage Slab


Thought you were trying to pour a feathered edge of "0" inches at the high end of the old SOG...

The thicker the thin end the less call backs, I'd consider re-pouring slightly out of level to add an 1/2" at the high, unless it is a lab or something that requires true flatness.

Chopped fibers to increase the average size of concrete cover post cracking?
__________________
I might be an Idiot, but I know things that You don't: Please wait till after you get my know-how to insult me....
Fouthgeneration is offline  
The Following User Says Thank You to Fouthgeneration For This Useful Post:
Rio (09-12-2019)
Old 09-12-2019, 07:06 PM   #13
Eater of sins.
 
ScipioAfricanus's Avatar
 
Trade: Designer/Drafter/General Contractor(again)
Join Date: Sep 2008
Location: Orange County, CA.
Posts: 4,058
Rewards Points: 1,956

Re: Leveling A Concrete Garage Slab


Most AHJs accept red guard.

I have used and it does work well for sure.

Andy.
ScipioAfricanus is offline  
The Following User Says Thank You to ScipioAfricanus For This Useful Post:
Rio (09-12-2019)
Old 09-12-2019, 09:17 PM   #14
Designer/Contractor
 
Rio's Avatar
 
Trade: General Contractor
Join Date: Oct 2009
Location: San Diego city/County, Cali
Posts: 3,196
Rewards Points: 2,372

Re: Leveling A Concrete Garage Slab


Quote:
Originally Posted by ScipioAfricanus View Post
Most AHJs accept red guard.

I have used and it does work well for sure.

Andy.
Thanks so much!
Rio is offline  
Old 09-13-2019, 01:38 PM   #15
Contractor
 
AustinDB's Avatar
 
Trade: Remodeling & Home Additions
Join Date: Sep 2006
Location: Austin, TX
Posts: 4,353
Rewards Points: 1,186

Re: Leveling A Concrete Garage Slab


Quote:
Originally Posted by ScipioAfricanus View Post
Most AHJs accept red guard.

As a bonding agent or vapor barrier (only)?
AustinDB is online now  
Old 09-13-2019, 04:00 PM   #16
Eater of sins.
 
ScipioAfricanus's Avatar
 
Trade: Designer/Drafter/General Contractor(again)
Join Date: Sep 2008
Location: Orange County, CA.
Posts: 4,058
Rewards Points: 1,956

Re: Leveling A Concrete Garage Slab


I have only ever considered it as a VB.

Andy.
ScipioAfricanus is offline  
Old 09-13-2019, 05:23 PM   #17
Designer/Contractor
 
Rio's Avatar
 
Trade: General Contractor
Join Date: Oct 2009
Location: San Diego city/County, Cali
Posts: 3,196
Rewards Points: 2,372

Re: Leveling A Concrete Garage Slab


I was doing some reading up on it and since it is used with thinset I don't see why it can't be applied on top of the existing slab and then have the leveling concrete placed on top of it. The cost of it does start to add up if it's applied at the rate of 50 s.f. per gallon with two coats so I'm thinking of going with 10mil plastic up to about 2" of thickness then transitioning to the redgard with the redgard going under the plastic for 6" with a continuous bead of urethane caulking between the plastic and the redgard, think that should work okay to keep the water out.

The bone dry looks pretty good but without any independent testing I'm leery about using it.
Rio is offline  
Old 09-13-2019, 06:41 PM   #18
Pro
 
Fouthgeneration's Avatar
 
Trade: Masonry
Join Date: Jan 2014
Location: Middle
Posts: 2,431
Rewards Points: 8,691

Re: Leveling A Concrete Garage Slab


Last minute "brain Wave": tapered, high density foam board cut by roofing foam jobbers? XPS type

E.g. use 4" thick foam cut at floor angle, do the 'low' end, use "scraps" at high end.

Gives you warmer/cooler floor?

~6-8.00$ / Cubic foot, = 161-216$ / yard...

Some studies show closed cell picks up less moisture over time =Better R value later... I'd use the stiffest product for less cracking. Or just install a VB under the foam.
__________________
I might be an Idiot, but I know things that You don't: Please wait till after you get my know-how to insult me....

Last edited by Fouthgeneration; 09-13-2019 at 07:48 PM.
Fouthgeneration is offline  
The Following User Says Thank You to Fouthgeneration For This Useful Post:
Rio (09-13-2019)
Old 09-13-2019, 07:26 PM   #19
Pro
 
rustyjames's Avatar
 
Trade: Constructioneer; LEED AP BD+C
Join Date: Aug 2008
Location: Central NJ
Posts: 1,303
Rewards Points: 1,722

Re: Leveling A Concrete Garage Slab


@ Forthgen: Good thought but tapered roofing insulation is typically closed cell PolyIso, and I don't think that it would be best practice under cementitious materials.

Edited to add that I was unaware of XPS tapered insulation, so that could be a viable solution.

Advertisement


Last edited by rustyjames; 09-13-2019 at 07:49 PM.
rustyjames is online now  



Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Join Now... It's Fast and FREE!

I am a professional contractor
I am a DIY Homeowner
Drywall Talk is for
PROFESSIONAL CONTRACTORS ONLY!

At DrywallTalk.com we cater exlusivly to professional contractors who make their living as a contractor. Knowing that many homeowners and DIYers are looking for a community to call home, we've created www.DIYChatroom.com DIY Chatroom is full of helpful advices and perfect for DIY homeowners.

Redirecing in 10 seconds
No Thanks
terms of service

Already Have an Account?