insulating concrete

deere2440

I am going to pour a concrete floor for my garage and plan on putting pex in it for heat. My question is should I insulate my pad & or footer? If so with what and where to put it? I dont want the most energy effecient garage ever but I do want it to stay heated.

billie_t

i would suggest insulating under the slab and up the inside of the wall to the height of where your studs will start... you want to visulize you heat not being able to get out of the concrete...i used 2 inch styrofoam...some use only bubble wrap..i guess go with what you can afford..but my choice was more is better

deere2440

If I pour the footer first could I just insulate under the pad & between the pad & the footer? Along with up the inside.

billie_t

you can do what you like, remember heat does not just rise..when you think radiant..think..heat goes to cold.. your heat will travel through your cement in any and all directions..where ever it does not run into insulation, ,will be heat loss, so you want as much "heat loss" directed into your living space as possable and the least amount of "heat loss" anywhere else

insulate the floor as best you can...think of your insulation as a big bowl holding your heat...if there is a crack anywhere you have a little leakage..the bigger the crack the faster the leakage and the faster you have to add heat to keep the bowl full

leaks cost fuel..fuel costs money...there may be times you have to live with a little leak or two...keep them as small as possable

concretemasonry

Insulate under the interior floating slab with EXTRUDED polystyrene with some strength and not EXPANDED polystyrene (the beadboard that is only used for coffee cups, etc.).

You could insert a thin (1/2" to 1") extruded polystyrene layer between the slab and the stem wall. If you are pouring a structural slab instead of a interior floating slab, you just have to accept the heat loss out the edges of the slab to exterior.

Chris Johnson

Product called Warmedge for the slabs edge and foam below

Personally I don't like foam below a garage floor, they still make a tinfoil bubble product I know most guys will thrash on but in a garage I would rather use that and use foam in the basement.

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Chris

deere2440

My thoughts were to dig a 12" wide 30" deep footer and pour it first. Then come back and place my insulation, pex & pour the slab. Im just worried that if it is all one piece that the footer will settle and crack the slab.

Chris Johnson

If the footing settles you have bigger worries than a cracked slab...it is a major structural defect!!!

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Chris

deere2440

I just mean 1/2 inch or so over many years time. I was told by a local contractor that if I pour it all at once that this is a concern. He said if I was to do it all at once I need to cut a break point just inside the walls all the way around the building or it could settle and break the floor in the middle. I figure it is easier to just pour the footer and let it cure then pour the floor inside of it so that it is a seperate piece all together.