Pour new concrete over old ?

[washnvac]

I have a 4 bay wash (2 auto/ 2 s/s) that needs all new concrete and floor heat tubing. I have a vendor that says it will be fine to lay new tubing over old concrete, then pour 4 to 5 inches of new concrete over it.

Has anyone ever done it this way ? If yes, what are the results ? Obviously this way is about 55% of the cost of ripping all of it out; then re-pouring. I am concerned if it will hold up without cracking in the future.

 

[Ric]

I did the exact thing to one my washes about 25 years ago. It's still going strong today. The contractor did tear out the aprons so he could bring the new floor down to asphalt level. Pit grates had to be framed up also. I would not hesitate to do it again.

 

[wash4me]

As long as you don't feather it out at the edges (it remains a full 3-5 inches clear to the edge) I think it would be fine.

 

[lag]

Will it effect the vehicle height you can accept in the two auto bays?

 

[Randy]

I have a 4 bay wash (2 auto/ 2 s/s) that needs all new concrete and floor heat tubing. I have a vendor that says it will be fine to lay new tubing over old concrete, then pour 4 to 5 inches of new concrete over it.

Has anyone ever done it this way ? If yes, what are the results ? Obviously this way is about 55% of the cost of ripping all of it out; then re-pouring. I am concerned if it will hold up without cracking in the future.

How much is this project going to cost you? My bay floors are in pretty bad shape. The idiot who built my car wash 35 years ago poured the floor over the dirt, no rock ballast, no rebar or wire. There getting pretty cracked now.

 

[washnvac]

Complete demo, and new floors is about $35,000. This is with me doing the labor installing the floor heat tubing.

Pour over old, with me doing the labor on the floor heat tubing is about $19,000.

Lag-- Yes it would affect autos. They are lasers, so I would have to raise the units up to keep 7' clearance. I have not gotten a price on that yet, but it seems to me that is not too complicated. The s/s bays- one is already 12'6", and the other 9'6", so that is not a big deal to lower that clearance.

 

[slash007]

I've been thinking about doing that to get new floor heat intsalled, but can't afford to lose the 4-5" in bay height. Any pictures of completed pour overs would be great.

 

[sparkey]

Seems like you would need twice the BTU's to heat the concrete slab pouring another floor on top of the existing floor.

 

[mjwalsh]

We poured over ours for part of our car wash & our dog wash. I could be wrong but I think the over 10 inches of accumulated concrete height also makes it stronger in case something extra heavy travels over it or mounted on top of it.

 

[DiamondWash]

My concern would be what caused the original concrete problems would eventually makes it's way into the new concrete.

 

[washnvac]

My concern would be what caused the original concrete problems would eventually makes it's way into the new concrete.

Bought this location out of bankruptcy. Previous owner thought it would be a good idea to plumb the floor heating system with water; and constant fresh water pressure feed. Gas meter was removed years before we bought it. Needless to say, it was busted in many places. We have jackhammered and fixed many. But these have just been temporary repairs; as floor it just cracking up all over the place. It is time to fix it properly.

 

[mjwalsh]

Bought this location out of bankruptcy. Previous owner thought it would be a good idea to plumb the floor heating system with water; and constant fresh water pressure feed. Gas meter was removed years before we bought it. Needless to say, it was busted in many places. We have jackhammered and fixed many. But these have just been temporary repairs; as floor it just cracking up all over the place. It is time to fix it properly.

That is an example of if the cement is kept from freeze thaw via deicer ... it tends to stay in a much more pristine condition.

 

[DiamondWash]

Could you post pictures of the concrete you are going to replace?.

 

[DiamondWash]

Have you started/completed this concrete project? I'm really interested on how it turned out.

 

[washnvac]

Negative; I have not decided what I am going to do yet. I am awaiting the contractor to come back so I can get firm pricing on both avenues. It may be a few months. Whatever I decide, am going to try and complete in September. I will let you know.

 

[DiamondWash]

I have been researching "concrete resurfacing" lately and it's got me thinking about it alot more now, as I too have cracking in my bays but from what I have seen and heard a 1/4" resurface would solve my issues, 1/4" resurface just doesn't seem very durable in our application considering we get a lot more traffic then typical driveways.

 

[MEP001]

Years ago I saw a product that was basically an epoxy mixed with concrete and some sort of fiber reinforcement that could spread thin on top of existing concrete. I haven't been able to find exactly what I remember.

 

[VetteCity]

OP
I have never poured any concrete with floor heat but I have poured many caps on existing concrete some as thin as 2 inches most were 4 inches and all held up well. It is my experience that the extra thickness and the grout that settles in the cracks from the new pour stabilizes the broken concrete underneath. That being said none of these were car washes but most had heavy truck and trailer use(not semi tractor and trailer). I am not sure if you can use fiber in the concrete with floor heat but if you can I would pour the first 2 inches with fiber and the top without for a smoother finish.

 

[VetteCity]

I have been researching "concrete resurfacing" lately and it's got me thinking about it alot more now, as I too have cracking in my bays but from what I have seen and heard a 1/4" resurface would solve my issues, 1/4" resurface just doesn't seem very durable in our application considering we get a lot more traffic then typical driveways.

I have used several different skim coats we call them and I have yet to find one that will hold up to pressure washing.

 

[VetteCity]

Years ago I saw a product that was basically an epoxy mixed with concrete and some sort of fiber reinforcement that could spread thin on top of existing concrete. I haven't been able to find exactly what I remember.

We have applied many different High build epoxy coatings in factories and mixed them with a variety of fillers for traction and they are very expensive. In my area it would be cheaper to pour a cap on existing concrete if you have the height.