Barndominium/Shop or "real" House?

[EddieWalker]

At least you know that you have your base rock compacted really well!!!!

 

[hayden]

I have always seen sub-slab work done before the building goes up, not afterwards. It what you are doing the norm in your area? Or is there some other reason for doing the building first, and floor second?

 

[ETD66SS]

I have always seen sub-slab work done before the building goes up, not afterwards. It what you are doing the norm in your area? Or is there some other reason for doing the building first, and floor second?

Yes. On a post frame, the building goes up before the slab. The weight of the structure is transferred through the columns into the footers. The slab is poured around all the columns. This is standard practice here.

 

[ETD66SS]

Speaking of the columns, I asked the Amish crew to not backfill them with the sandy load soil, they did anyways. So now I have to dig that soil out and replace with crusher run.

That soil just will not compact with the jumping jack, the foot just disappears into the soil and the whole area floats, it's still too wet and I don't trust that the soil will stiffen up anytime soon.

For the first concrete pour, I have to do this for 27 columns...

 

[ETD66SS]

Getting ready to run the pex for the garage slab. Wondering if I should or should not run pex under the stairwell?

Seems like it might get too hot in there, this will be all one heat zone.

 

[Carl_NH]

I would agree as it appears that's where the PEX is terminating (under the stairs). Also will the water heater for the radiant hear go under the stairs too? That area is in the middle of the building too, so it will get residual heat from the surrounding slab.

 

[MossRoad]

Getting ready to run the pex for the garage slab. Wondering if I should or should not run pex under the stairwell?

Seems like it might get too hot in there, this will be all one heat zone.

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Can you valve off the stairwell for future use/non-use? Now's the time to install it. You'll have a tough time going back.

 

[ETD66SS]

I would agree as it appears that's where the PEX is terminating (under the stairs). Also will the water heater for the radiant hear go under the stairs too? That area is in the middle of the building too, so it will get residual heat from the surrounding slab.

The boiler will be on the upper level, so not on the 1st floor. Under the stairwell will be a 7-branch manifold collecting all the loops from the garage and workshop.

My take is that part of the concrete will get somewhat heated by the adjacent loops.

I could put in another single loop manifold and some tubing if I ever needed to heat that area but is that really needed? Could I just add tubing to the bottom of the stair treads in the future if I ever wanted to heat the area above the stairs?

 

[civilian]

Are you going to be crawling or laying or walking barefoot under the stairs? That is the only way you will notice the concrete is not heated. Jon

 

[ETD66SS]

Are you going to be crawling or laying or walking barefoot under the stairs? That is the only way you will notice the concrete is not heated. Jon

There will be a door to the under stairwell cavity. What will be in there is the main water shutoff, and the 7-branch manifold. That's pretty much it.

I don't see myself going in there very often.

The issue is really if the stairs leading up to the second level need to be heated or not...

 

[WinterDeere]

Can you valve off the stairwell for future use/non-use? Now's the time to install it. You'll have a tough time going back.

Agreed. PEX is cheap, install it now, as a separate loop. No one says you need to connect it, just install it.

 

[ETD66SS]

Any AC experts/installers?

One other thing before the concret pour.

I want to have central air in the living space.

Should I put in some conduit sweeps that go under the skirt board and up through the slab into the wall for the AC condenser power and refrigerant lines? Or would these just go through the wall above grade?

I'm thinking they would need to go above grade so there is no water sitting in the conduit.

 

[LittleBittyBigJohn]

They run through the wall on the house I just had built. But my AC units are in the attic, which could be less than ideal according to who you talk to.

 

[Carl_NH]

Agree with you LBBJ - thru the wall for the line sets and usually a electrical disconnect box next to the compressor. As far as the air handlers, many are put in attics, and these can be problematic if the drain pan leaks or drain hole is plugged. If possible put the air handler/heat exchanger in the basement or ground floor with a drain

 

[EddieWalker]

When I built my house, I ran two-inch conduit from the mechanical room to the side of my house where the outside unit will be. At the time, I thought it would be better than running the lines through the attic space.
It worked fine, but when we had the unit replaced, the went up through the attic for the new lines and there never was an advantage to having the lines under the slab.

 

[WinterDeere]

I've always seen refrigerant lines punched thru the wall a foot or two above grade, never below. Even on new construction.

I'd suspect the losses of having them below grade, whether direct burial or in conduit that's almost certain to end up wet, runs any other advantage of trying to put them below grade.

Look at all the issues the outside wood boiler guys have with running their line sets below grade. They show it can be done, but it's certainly not the easy or efficient way to get three feet of exposed line from outside to inside.

 

[ETD66SS]

I'm ready to start running my pex:

Used one of those foam heat knives to take off some nubs where the manifold will be located.

 

[EddieWalker]

Do you weave the PEX through the bumps on the foam?

 

[ETD66SS]

Do you weave the PEX through the bumps on the foam?

Most of the videos I watched guys were stepping on the pex to force between the nubs. At first I did this but it was causing the edges of the styrofoam to break off. I soon found a method which worked way better. I would keep an arc in the pex so it generated downward pressure via a spring force while very slightly weaving the tube back and forth. You only have to move about 1/8 inch back and forth.

This worked much better. It simultaneously fully seated the pex and there was no damage to the foam. Also no need to go back over to make sure the pex is fully seated.

One bad thing about this methid is you have to be closer to the foam so have to bend over quite far. After each loop my lower back was on fire.

 

[Carl_NH]

Looks really good - nice, clean installation!