Pour new concrete over old ?

[sparkey]

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.

I had to repour my automatic bay a couple years ago. I used fiber in the concrete and the floor heat has no issues.

 

[DiamondWash]

OMG I starting to hate concrete right now, our slabs are finally settling and the cracks are appearing everywhere in my lots n,e,s,w, had a company come out to quote me "just my backlot" at 4,925 Sq Ft with 6" thick C4 concrete $35,050.00 and that doesn't include the areas with floor heat, so I ask this if you had to demo out your concrete would you replace with asphalt I know the price of oil dictates the cost of it but $35k

 

[MEP001]

You shouldn't need 6" concrete unless you have fully loaded dump trucks going over it regularly. A proper base and 4 1/2" is the standard here. Asphalt needs an even sturdier base to not shift and crack, so your cost won't be a lot less if asphalt is done right, and if it's in an area that will get wet a lot it won't last 20 years.

 

[DiamondWash]

Majority of our business is commercial traffic such as: FedEx, UPS, Construction vehicles, RV's, Etc were going on 16 yrs here, so we are at that time to probably replace the concrete because I think we have hot poured the cracks over the years to the point of no return. I've seen some wash owners just pour a slab in the front and rear of the bays and have gravel for the parking lot LOL.

 

[6t7gto]

Over $6.00 a sq. ft. seems high.
I did 5" concrete 23 years ago and mine is fine.
UPS, Fedex, garbage truck, semis cutting thru to neighbors building.