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Floating concrete garage floor thickness
Mr Whippy - 11/3/24 at 12:49 PM

Ok so it probably a bad title as it's not floating but on foam, however it’s all I could think of.

As my wife refuses to let me park the old car in the living room (such a heartless savage woman) I’m forced to build a new garage of the side of the old one. This will be specifically for safely storing the Prefect, thus one of the conditions is that it is to be so heavy insulated I can then afford to heat the garage space. To achieve this for the floor, I want to pour a slab on top of 100mm EPS100. As the Prefect only weights 850kgs and this garage is not for working it, therefor no axle stands or jacks will be used. What do you think the thickness of the concrete floor should be? I was thinking 4 inches with rebar grid would be more than enough? Seeing that the concrete is on top of foam… The floor is 3m x 6m. My other garage floor is 8 inches thick with rebar and I haven't broken that yet but that rests on the ground.



[Edited on 11/3/24 by Mr Whippy]

gremlin1234 - 11/3/24 at 02:30 PM

have you considered using underfloor heating?

Mr Whippy - 11/3/24 at 03:19 PM

quote:
Originally posted by gremlin1234
have you considered using underfloor heating?


Yeah I have actually and it's a good suggestion, I was thinking of imbedding plastic tube in the concrete and a solar water heater panel on the garage roof. I think it would work great as during the day the hot water would warm the concrete up and then the floor would heat the garage during the night like a huge storage heater.

Years ago I made my own solar heater using a pair of large radiators placed in boxes with glass windows, the water that came out in the summer was too hot to touch.

I'd be too wary of electric underfloor heating due to the weight of the car. The garage walls and ceiling will be 150mm rockwool slabs and 100mm used in the wooden garage doors.

designer - 11/3/24 at 03:22 PM

I would have thought than 4in thick, with rebar, would support a truck.

gremlin1234 - 11/3/24 at 05:01 PM

quote:
Originally posted by Mr Whippy
I'd be too wary of electric underfloor heating due to the weight of the car.

I would be just as wary about piping.
both electric and fluid systems: I would run many individual elements, configured so they can each be isolated if/as they fail.

[Edited on 11/3/24 by gremlin1234]

Mr Whippy - 11/3/24 at 09:08 PM

quote:
Originally posted by gremlin1234
quote:
Originally posted by Mr Whippy
I'd be too wary of electric underfloor heating due to the weight of the car.

I would be just as wary about piping.
both electric and fluid systems: I would run many individual elements, configured so they can each be isolated if/as they fail.

[Edited on 11/3/24 by gremlin1234]


It is true, it would be wise to leave each loop exposed out of the concrete to allow later bypassing if necessary, a good point thanks

ianhurley20 - 13/3/24 at 10:01 PM

Mine is at the side of the house, firstly about 4" of various hardcore topped with an inch or two of sand then DPM and 105mm of phenolic foiled insulation (rejects as it was supposed to be 100mm!), then 4" of concrete with a scree of self leveller on top followed by screwfix grey floor paint. It's been there 6 years now and has had the kit car, trailer and all sorts of things on it with no issues and is very good at keeping the place warm (along with more 105mm insulation in walls and roof)

Mr Whippy - 14/3/24 at 07:28 AM

quote:
Originally posted by ianhurley20
Mine is at the side of the house, firstly about 4" of various hardcore topped with an inch or two of sand then DPM and 105mm of phenolic foiled insulation (rejects as it was supposed to be 100mm!), then 4" of concrete with a scree of self leveller on top followed by screwfix grey floor paint. It's been there 6 years now and has had the kit car, trailer and all sorts of things on it with no issues and is very good at keeping the place warm (along with more 105mm insulation in walls and roof)


Perfect thanks sounds just what I'm after, glad it's holding up.