Olson's new house build is going hydronic

[colson04]

I've been a lurker around here for awhile, finally decided to join so I could participate more in the forum. I really enjoy the knowledge base here and the DIY attitude.

Long story short, I'm a dairy farmer with an engineering degree building a 1600 Sq ft ranch house for my family. Originally, the heating and cooling plan called for a traditional forced air system with heat and DHW supplied by my OWB. The garage, however, was planned for in slab radiant.

As I started digging into what I needed to do to put a radiant system together for my garage, I learned that it wasn't too late to add radiant heat to the house, even though the basement floor had already been poured. So, we've scrapped the forced air idea, and now I'm doing my own radiant heat for the entire house. We will be pouring the garage slab next Saturday and I will be spending the next week prepping everything to make it as smooth as possible. I'll be posting pictures of my progress and asking questions along the way.

My goal for this thread is to share my experience, and also to gain advice and wisdom from other members regarding hydronic heating systems. I've learned a lot since finding your site and look forward to learning more and also helping others when possible.

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[hondaracer2oo4]

Don't forget the thermal break to the frost wall with the garage pour!

 

[Wook660]

Yikes, only a week to gather supplies and install? I don't know how big your garage is but as previously stated you're going to want to insulate below and on the sides of the slab. The proper insulation could be tough to source in large quantities in that time frame. I had to put an order in and it took about a week to get. Make sure you plan for any future add ons, for instance, I'll be installing a 2 post car lift and left two 24 inch circles free of pex. You don't want to risk drilling through your lines. Make a manifold with a gauge so you can put the loops under pressure and monitor them before pouring and during the pour. You don't want to find out later that there's a leak somewhere out of sight in the concrete. Here's an example of how I did mine. First the insulation, a vapor barrier, and then the pex tied to the wire mesh to keep it in place.

 

[colson04]

Well, I'm a little farther ahead than that. I have my barrier pex for the floor, manifolds, and layout plan done. I have not picked up the insulation, but from what I have read, 2" XPS foam is the preferred choice along with a 6 mil vapor barrier. Both of those products are readily available from multiple sources locally. We will be doing the excavation work today. We have to excavate some clay out of the garage area, and then backfill with compaction sand. That will consume most of my day today.

Materials List:
3 Loop Manifold
(3) 300 ft Oxygen Barrier PEX lines
Pressure Test Assembly
725 sq ft 2" XPS Foam
650 sq ft 6 Mil Vapor Barrier

I think I'm on the right path so far, but input and suggestions are always welcome.

 

[hondaracer2oo4]

Run the thermal break beveled piece of foam board even with the top of the slab. Don't keep it low by 1 inch like your pic shows.

 

[BoiledOver]

Run the thermal break beveled piece of foam board even with the top of the slab. Don't keep it low by 1 inch like your pic shows.

For those of who don not know, can you explain why? Should it be beveled still?

 

[maple1]

Wondering if 2 layers of XPS on the bottom would be worth considering? I have no idea, just curious. Hoping to do a garage here someday...

 

[hondaracer2oo4]

@BoiledOver. The reason is that the frost wall is pulling all of the heat out of the slab and transferring the heat through conduction to the very cold outside air temp on the other side of the wall. You want to make the slab sit in a foam tub surrounded on all sides and the bottom by foam separating it from the ground and the frost wall which is where you don't want your heat to go. Most people bevel the top so that you can't see the foam but it runs all the way to the slab height. No real concern of breaking this section of concrete because how much weight are you going to put 2 inches from the frost wall edge?

 

[colson04]

That's why I posted my plan. My dad thinks I'm nuts for putting the foam on the edges at all as he is concerned about the strength of the concrete. I agree, for a residential garage, you aren't going to put a high load right against the wall. And if you are thinking about shelving, you can plan ahead and space them out from the walls an extra 2 inches

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[hondaracer2oo4]

You might as well put no insulation at all under the slab if you don't thermal break the frost walls. The insulation against the frost walls is the most important. Thermal breaking across the garage doors and man doors is usually skipped but is another place where you can lose heat from the slab. Whatever you do don't skip the frost wall break!

 

[colson04]

Installed the pex tubing on Thursday and pressure tested Friday. Poured the floor today. All phases went very smoothly and the only air leak we had was on a threaded fitting for the pressure test assembly. A couple more wraps of Teflon tape cured that.



I need to swap out the manifolds, I initially was going to install 3 loops, but 2 covered more than sufficiently for a garage. I'll change those out before we start actually heating the house.


Finished product



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[colson04]

And yes, we poured the concrete ourselves. Took forever to finish being in the shade on a cool day with a vapor barrier below it. All of the water had to come up before we could get a good finish

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[mcdougy]

Looking good....what's your plan for a/c? I'm going to be building a ranch house in the spring and I am interested in your build. BTW im a contractor in ontario, who grew up on a dairy farm.

 

[jebatty]

Did you consider 2" perimeter foam extending down 4' (to frost depth) to prevent freeze creeping under the foundation wall?

 

[colson04]

Did you consider 2" perimeter foam extending down 4' (to frost depth) to prevent freeze creeping under the foundation wall?

It was discussed but deemed unnecessary since it is a garage and slab is isolated by 2 inches of foam all around. I'm not heating my garage to 70 all winter, just keeping it above freezing most of the time. I'll kick it up to 55 or so if I want to work on something, but that won't be daily.

My last garage only had R13 in the stud walls, nothing under slab or against foundation walls and it never got below freezing until late January. I'm not overly concerned I guess. It'll probably use a touch more wood, but we can't keep up with the dead trees on the farm anyways.

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[colson04]

Dug the trench from my OWB to the house this morning. Trench started at 6 ft deep, dropped the 1 1/4" poly line for my well in along with well electrical. Backfilled 2ft, leveling and compacting as we went, then laid down some Tyvek to isolate from the dirt, dropped in my 1 1/4" pex tubing and started foaming in place. I went with the DOW Froth pak from menards. Could have shopped around more, but I've used it before and still had the gun assembly for it. Unable to finish project due to pop up shower. Still have about 2/3 of line to foam. Hopefully, we will be able to finish tomorrow, but if not, we'll get it done Friday.



I'll get some more pics tomorrow. Rain ran us off before I took any of lines being foamed.

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[Woodfarmer1]

Looking good....what's your plan for a/c? I'm going to be building a ranch house in the spring and I am interested in your build. BTW im a contractor in ontario, who grew up on a dairy farm.

I used a ductless ac unit

 

[colson04]

Lines were laid and foamed in place. I did use the pink board to make a trough to help meter the correct amount of foam. Afterwards, I hand covered and packed the entire 130' run by hand. Then my dad followed behind and back filled the rest with the bobcat.

Overall, the process went fairly smooth, it did take a little while to figure out how to shoot the foam in fairly efficiently. Once we got it done it went quickly.

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[colson04]

Anybody read Money Mustache?

He had a couple threads related to hydronic heating.

http://www.mrmoneymustache.com/2014/02/16/the-radiant-heat-experiment/

http://www.mrmoneymustache.com/2015/02/06/the-radiant-heat-experiment-did-it-work/

I ask because I'm thinking of using a similar method to tie in my OWB. Replace the on demand water heater in his system with a correctly sized flat plate heat exchanger to keep my boiler water separate from the potable water and I should be all set. I like the simplicity of both the construction side and the operation side.

Thoughts?

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[Fred61]

How did you keep the supply and return separated during foaming?

 

[colson04]

How did you keep the supply and return separated during foaming?

I zip tied blocks of pink board 2 inches thick between them about every 4 ft. This kept the lines spaced 2 inches apart really well. Anywhere they got too close together, I would shoot some foam underneath and between the lines, then hold them apart for 20 seconds or so to keep them apart. Once the foam expanded and tacked up, I would let go and finish spraying them in. I only had to do that in the corner section of my run.

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[Fred61]

That seems a lot easier than most of the techniques I've seen.

 

[colson04]

I haven't forgotten about this thread, I just haven't been working on the heating project for a few weeks. Finally got the outside projects done on our build and getting back inside.

Here's a crude diagram of my intended plumbing setup. Any thoughts?



The outside, open system will be separated from the indoor, closed system by a 60 plate brazed heat exchanger. The basis is a primary - secondary piping system that puts the DHW heat exchanger right in the primary loop. That would allow me to isolate the radiant system out and burn wood a bit longer into the warm season. I don't plan on burning all year long, but I do like to burn longer than most around here. I will be zoning with deltaT Taco 008 circulators.

I'm still new to hydronic heating, but I'm trying to learn as much as I can as fast as possible.

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[Nofossil]

I don't know if this is an option or not, but if you have potential space for heat storage, at least plumb with stubs to add it later if you can. Since you plan to burn longer into the shoulder seasons, storage will allow you to burn hotter and more efficiently, then live off of storage when the boiler isn't running. Ideally heat storage would be on the pressurized side of your HX.

We burn a short hot fire every two or three days this time of year. Storage lets that happen while maintaining constant house temps and ample DHW.

 

[colson04]

Storage is part of the plan, but not this year. I'm leaving a space aside for it and a way to plumb it in. I just dont have time or budget to expand the scope of the project this year. I'm not against it, it just doesn't fit into the scope of the project this year.

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