radiant slab heating pex routing questions

[Husky79]

Hi, I live in north central MN, it can get down and stay in the negative temps for a month or 2, and I have some questions about doing my in floor heating setup before pouring concrete this friday.

most of the lines are 12" spaced from each other.

I am wondering if pex can cross over each other?

How close apart from each other should they be on the supply/return alley?

How far should the exterior perimeter pex be from the slab exterior perimeter?

I have attached 2 images, both are same design, just different background color. Not sure which appears better for each person viewing.

217 master bedroom
217 green guest room/office
224, 237, and 279 are one big open space with 279 being the kitchen
100 is utility/bathroom where the boiler/manifold will be mounted.

140,226,286, and 297 are shop area. 140 is where work bench will be, 297 is what I call a apron, where trench drain will be and where I melt the snow off snowmobiles and equipment before completely bringing them further inside the shop.

The garage door is right below 297 not on the right. the area on the right will be another insulated building with its own radiant slab heating.

 

[jack stand]

All I know is my system that I paid for the design work. This allowed me to do the installation 100% but.
your design seems *odd with the amount and length of "alley's" in it. For example the right side "loops" seem to be divided top to bottom vs. left to right. This would eliminate a lot of these alleys that would save you a lot of tubing and labor.
I have no alleys in my design as every line is spaced to deliver btu's, not running tightly spaced past another loop just to get to the far side.
Unless you are having some of your little 100' loops being a zone, I'd combine them and disregard the future wall layout. Just keep the tubes low in the slab, use glue and nails that only penetrate the slab by 3/4" when building your partitions.
Unless a separate zone, your tubing can pass from one space to another. Run your design again without the interior walls.
I'll let one of the pro's suggest the exterior tube placement, spacing and flow direction. My thinking is (especially with your temps) would be this is the area with the highest heat loss (load) and should get the hot water first and maybe a 1/2 (6") spacing for 2 -3 runs of tubing against the exterior.


*to my very limited experience

 

[Husky79]

btw

217 master bedroom
217 green guest room/office
224, 237, and 279 are one big open space with 279 being the kitchen
100 is utility/bathroom where the boiler/manifold will be mounted.

140,226,286, and 297 are shop area. 140 is where work bench will be, 297 is what I call a apron, where trench drain will be and where I melt the snow off snowmobiles and equipment before completely bringing them further inside the shop.

 

[PoorUB]

You can cross the tubing but with a minimum of planning you will not have too.
Run your supply side out, fill the area, and the return back and repeat. Watch how you run the supplies and return tubing and try space it out. It will get tight right at the manifold, unavoidable.

Relax, it is just about impossible to screw up floor heat tubing!