Method to Insulate Existing Slab

Just what would you insulate it with? What about the floor elevation change? What about utilities connections? What about whatever is connected to the slab?

It's unfortunate when construction doesn't meet the needs of the customer or the customer isn't informed well and later finds he wants radiant floor heat or the original installer uses bubble wrap in lieu of insulation.

The value of insulation maybe greater [compared to replacing the slab] than the factors you've stated and work around are quite straightforward - cut around them. Elevation change is acceptable. Insulate with closed cell foam unless other is better

Well, OK.

If you can live with the elevation change, and there will be no interferences, there is a technique you may want to investigate.

Concrete leveling or lifting can be accomplished with expanding foam. This is a niche market, and I don't know of anybody in particular to suggest. These guys have an online brochure describing the process. The brochure only described industrial use, but have a look and see what you think. It should be adaptable for what you are describing.

Bubble wrap! R-value of 1?... not too good!

Thanks this form was unknown to me and we shall see...results will be posted.

Is something like this out of the question?

Heated Floors - Radiant Floor Heating Systems

Yes essentially it's the heat system desired but in the upper Midwest you know we need insulation under the slab. Some existing properties do not have insulated slabs and the heating costs are prohibitive. Imagine building on the rock of the Buffalo Ridge or Blue Mound without insulation how much would it cost to heat that rock

Radiant heat can be used with existing concrete slab employing several systems mainly laid over the slab and then float a thin (2") layer of cement over. Another aspect is the thermal mass available when the slab is insulated appropriately.

the only possiblity is to pour another slab on top of the existing one. personally, i'ld remove the old slab and do it correctly.

I'm very surprise that no one has yet addressed a very important problem with slab jacking: most likely you will end up with a severely cracked floor slab. It all depends on how the floor is elevated. If you're using hydraulic jacks, then you're going to need a whole lot of them to elevate the concrete slab uniformly and very slowly. Under-reinforced and thin slabs will pose a larger problem for you and are more acceptable to cracking or even breaking apart. If this is an interior basement slab don't forget that you must first break the concrete bond along the foundation wall and around any interior wood or steel columns. Also, a problematic area will be if the column footings were placed integrally (ie, monolithically) with the floor slab.

Another concern is a life safety issue. Who is foolish enough to get underneath a jacked-up concrete slab so as to install the insulation? I don't recommend that anybody do this unless they have a death wish!!!!

You would be best served by just demolishing the existing slab, excavating the underlying subbase soil to the necessary depth, and then installing the required insulation and new reinforced concrete slab-on-grade.

Hi CaptMoosie,

Thanks for the stabilizing comments. Ya see we're intending to use expanding foam to lift the slab and since expanding foam is insulation we've killed two birds with that stone. Yes of course all restrictions will be cut allowing the slab to migrate an it's an interesting concept too. Some sites are basements and others are heavy equipment sheds which have appropriate reinforcement.

Been a little wet lately eh? Some interesting events taking place a long the Mississippi and about the levee system and the water level is up this year. It's a pity we can't use more water to recharge aquifers instead flushing it straight out to the ocean.
Many in west Texas would pay for it ya think?