Greetings everyone! 

   I was hoping I could get some feedback with a building I am working on. The existing concrete was a 3 inch "homeowner special", so the plan is to set 2 inches of rigid foam, tubing for radiant heat, and four inches of new pour concrete.

1.) Do I need anything between the insulation and the existing concrete?

2.) The radiant pipes have ties to attach to the iron rods for the concrete, so I can only imagine that the metal goes first, then the radiant...

3.) How do I protect the rigid foam from damage from walking on it to do the other steps?

4.) Does the rigid foam boards needs to be taped between each other and to the end of the block?

This is a very exciting project and your feedback is greatly appreciated, 


Tags: board, concrete, floor, foam, heat, installation, insulation, radiant

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What is the issues with the "homeowner special" concrete - wavy, falling apart, or... That can easily change some answers depending on the severity 

#1 - generally not needed, though sometimes you might need a floor leveler, maybe even a crack/moisture isolation membrane

#2 - Personally I like having the radiant around the halfway mark in the slab with the metal though many simply attach it directly to the foam like is shown here

#3 - use the proper foam & it can handle it - should be a high density closed cell foam

#4 - that is a very good idea

One last tip - make sure you have the pex lines pressurized while you are doing this and check them as you go - last thing you want to do is find out you have a leak after the concrete is set, while messy it is easier to fix now then later

Not sure if this would have any bearing on your project at all. Thought I would mention it though.
When we apply our coating on new concrete walls or new stucco, we always have to test the Ph level first. It must be no higher than 4, we prefer 3 or below. With concrete or stuccvo that is 5-yearsold or older, rarely an issue. Less than 5, many times an issue. It causes major bonding problems.
Again, not sure if a high Ph level concrete would cause issues with your foam or not. Possibly???
Some paint companies make a primer for high Ph surfaces. Might be a good thing to look into. Will a high Ph level concrete eat the foam??? I dont know, thats why I'm bringing it up.


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