Leveling old concrete floor

[yeldogt]

I'm trying to figure out the best way to level out an old garage floor so I can place a wood floor on top of it. My "studio" is two buildings ... the older being a 24 x 32 garage with the original sloped floor to the door -- the floor was strictly for utility and was never finished very well.

I got an estimate a few years ago to rip out the old concrete -- level with stone and insulate and then install tubing for radiant in a new slab ... about 15k. But in the back of my mind I really wanted a wood floor in this area ... I am thinking that maybe I could just over-pour the current concrete to level it out and then insulate and install something like Warmboard (I have used this before in a small space - it is $$) or another product to get me the radiant floor. I don't have enough height to install 2x lumber to build a floor structure.

Anyone ever do this ?

 

[theoldwizard1]

If the concrete itself is in good condition (no big cracks, no loose piece) you can just use a "self leveling cement" product.

There is a lot of prep required for such a product and you will be raising the floor by the amount that you apply.

Warmboard is a radiant heat system, so yes it is more expensive.

I think you would be better off with a basement subflooring product like Dricore. It can and should be leveled while it is being installed. The benefits are it provides a moisture barrier from the concrete, and an air space for insulation drainage.

There are a couple of different similar products on the market.

 

[yeldogt]

The floor slopes almost 3" from the back to the front -- this is the longer side .. it is actually 35'. So it is a lot to level. It is just above grade and I don't have any moisture problem.

The building currently has propane forced air heat -- so I was thinking some radiant would be nice.

I have heard of lightweight concrete -- that self levels -- but I do't know anything about it ... or if it is even used for this.

 

[mobiledynamics]

How High is the Foundation off the walls ? Slope may be a good thing......depending on build.

 

[yeldogt]

I'm not sure exactly what you referring to regarding the walls/ foundation ..... The floor is just about at the top of the block in the rear and is down over three inches when it gets to the other end.


I was thinking maybe I could put plastic down over the old slab and pour a new one over it up to the level of the block top and then put down sleepers with insulation between and then the floor system -- I would be about 3 1/2 inches above the block and the walls to the ceiling would be just under 8'.

 

[theoldwizard1]

I'm not sure exactly what you referring to regarding the walls/ foundation ..... The floor is just about at the top of the block in the rear and is down over three inches when it gets to the other end.


I was thinking maybe I could put plastic down over the old slab and pour a new one over it up to the level of the block top and then put down sleepers with insulation between and then the floor system -- I would be about 3 1/2 inches above the block and the walls to the ceiling would be just under 8'.

Won't work. If you are trying to pickup 3+" Most self leveling products will allow a maximum of 1" of "lift" in each application.

Read Quikrete's instructions.

It maybe cheaper to higher a carpenter and install custom cut sleepers made out of pressure treated 2x4. These can be attached to the floor using several different methods.

Any plastic vapor barrier should be applied the sub-fllooring NOT in contact with the concrete. This why products like DriCore work well.


Of course if money is no object and you really want a radiant heat floor (they are nice), bust of the old floor, add insulation and piping and pour a new floor.

 

[yeldogt]

This is not something that I am going to be doing myself. I understand that you can have professionals come in with some form of lightweight concrete that is more or less self leveling - I just don't know anything about it.

I did a small 20x15 single story addition to my house -- it was a slab/ foundation pour and I used the Warmboard over the slab with hardwood floor on top to match the rest of the house -- all connected to my current radiant system in the house. It works very well.

The reason I did not have the studio floor replaced a few years ago is that I want a wood floor. The one thing about radiant floors -- especially a high mass concrete one is they are very slow to respond - so they work best when left "on" and I want something with a quicker response --- and I'm sure putting the wood floor on top of the concrete is going to make it slower still.

When I did the Warmboard they recommended the vapor barrier directly on the properly constructed concrete slab (plastic w/ insulation under the slab).

The Dricore product looks to be designed for below grade situations when water may be a problem.

 

[ssentt]

Find an outfit that does mud jacking and get an esitmate. The cost can vary, but usually a base trip charge minimum of $150 + volume/yards of mud (concrete/mud mix ) they use.

 

[yeldogt]

Hay .. that mud jacking is slick! It is amazing all the stuff going on.

In my case the floor was poured to slop to what was the old garage door opening so I did not have any settling.

 

[ssentt]

Where I work we have two buildings adjoining built several yrs apart. Floating floors with a height difference of about 3" and no apparent settling. Mudjacking was done and raised lower floor to same height for a smooth transition from building to building. Thought this might work whether settling has occured or not. Estimate are usually free, might be worth asking a professional to see if it can be done & cost effective.

 

[yeldogt]

That is very interesting - I am going to look into it ... Thanks

 

[theoldwizard1]

The Dricore product looks to be designed for below grade situations when water may be a problem.

Water, at least in the form of humidity is ALWAYS present in concrete that is laid on grade (unless you live in extremely dry climate).

Placing plastic in direct contact with the concrete will cause condensation, that is water droplets.

Because DriCore sits above the concrete it actually allow air to pass underneath. This air also acts as an insulator. The plastic coated bottom keeps the moisture below the subfloor.

"Mud jacking", if feasible, is a good option. If you really want a hardwood floor on top, you need need a subfloor that is not in contact with the concrete !



Find the Holmes On Homes episode where he rips out the lady's wood floor laid on concrete repeating over and over, "Never lay a wood floor on concrete !"

 

[elevator joe]

The light weight concrete is called gypcrete its a great self leveler. I'ts used a lot of times over spancrete in apartment bldngs. It might work well for you given the fact that you don't have moisture problems. Don't know many more details about it but iv'e seen it work well on some pretty rough surfaces. Good luck!!!

 

[yeldogt]

Like a lot of situations -- it all depends. A slab on grade with proper insulation and poly should not have any moisture -- people install wood floors over them all the time. I did the warm board on top of the slab with 2x sleepers creating 1.5 inches for additional insulation -- a bit over kill -- but I wanted the extra insulation in case the slab did have any issues.

The dricore looks to be an interesting product -- and especially important where you may have some actual water intrusion from ground sources -- like below grade in a basement.

I'm in no way suggesting your concern about wood over concrete is not valid as many slabs are not properly protected.

I'm just wondering how an over pour would work in my situation vs the expense of taking it out

 

[bernialisha]

In my opinion concrete flooring and concrete wall coating are very good, and it's working is nice and life long living without any problem. For my home, i am using that one only, i am fully satisfied with that.