25x48 pole barn radiant floor install

[Bd234]

Greetings all,
I have gleaned so much valuable information from the garage journal over the years. Now, finally, I have a project to post about with questions.

We initially used a skid steer to regrade the clay base which was approximately 16 in different from front to back on the long side. We insulated the perimeter with 5 and 1/2 in eps slabs of foam from a salvage concrete dock. Our contractor brought in the gravel and spread it 4 in thick. Now we are cutting 7 in slabs and laying them staggered in a brick pattern on the entire floor. We intend to spray foam the gaps, lay two layers of 6 mil poly, 2-in metal chairs, wire mesh and then affix the PEX to that.
I have the following questions for these steps still to do.

1. Is there some other way of sealing the gaps besides spray foam?
2. What's the best tape to use for the plastic and should it be sealed to the foam perimeter edges?
3. Is there a free or cheap software that will allow me to design the tubing layout

Thank you, Bridgette

 

[Bd234]

My questions were a little vague. Here are revisions....

1. Is there an alternative to spray foam being the gaps that I'm missing?

2. What is the best tape to use to seal the poly to adjacent poly and do I want to seal it to the perimeter foam, curling it up the edges 4 in where the concrete will be and laying into the corner on the floor?

3. Eventually it will be a finished space so I ask the concrete contractor to cut 4 ft squares of expansion joints but not sure what the minimum depth is so we can be sure not to hit the pex.

4. Does anyone know of any software cheap or free that will help me lay out the pex design? It's standard 1/2".

 

[ConCretin]

1. Is there an alternative to spray foam being the gaps that I'm missing?

2. What is the best tape to use to seal the poly to adjacent poly and do I want to seal it to the perimeter foam, curling it up the edges 4 in where the concrete will be and laying into the corner on the floor?

3. Eventually it will be a finished space so I ask the concrete contractor to cut 4 ft squares of expansion joints but not sure what the minimum depth is so we can be sure not to hit the pex.

4. Does anyone know of any software cheap or free that will help me lay out the pex design? It's standard 1/2".

1. I don't think I'd bother doing anything at the gaps between the pieces of insulation. If you have a vapor barrier, it will stop water vapor transmission. The heat loss through the gaps in the insulation is insignificant.

2. The most tenacious tape I've come across is made by Stego for use in sealing their 15 mil vapor barrier. If you are considering any type of adhered floor covering such as epoxy, you might want to use their vapor barrier too rather than the 6 mil poly, which is merely a vapor retarder, assuming it survives the placement without a thousand tears.

3. When you say finished space, do you mean the floor will be exposed? If so, you probably want to avoid random shrinkage cracks on the surface? You don't need your control points spaced 4' apart to accomplish this. 8' to 10' should be fine with the joints cut promptly after finishing to 1/4" of the slab depth.

Placing the pex on top of the wire is a less than ideal. Generally you want the wire as close to the surface as possible to keep your shrinkage cracks tight but you'll need to hold it down a couple inches and secure it really well to avoid cutting into it with your control joints. I prefer to lay the vapor barrier first and then the insulation. You can staple the pex to the rigid before installing your reinforcing.

4. Can't help with this one.

Take a look at my Guide to Floor Slabs in the link below for some additional thoughts on placing a slab on grade.