in floor heat

[mjs97]

i have recently remodeled older house and am now heating it with owb with exchanger in furnace. now getting ready to finish basement and wondering about putting in floor heat in. could i put 1" insulation down, then pex tubing, and then pour new slab 2" thick over it. don't know if this work orshould i take entire existing floor out and pour whole new floor.

i have heard in floor heat is very nice, and will help heat entire house by having it in basement floor. true?

any help is appreciated,
matt

 

[Streblerm]

I have given this quite a bit of thought as I am planning on turning my garage into living space.

I was planning on 1" of foam over the existing concrete with another layer of either foam, or plywood routed to accept the pex tubing. Then I was going to put laminate flooring over the pex/plywood/insulation.

 

[HUSKYMAN]

The only thing I dont like about the plan is the fact that the two sections of concrete will be completely isolated from one another by the 1" foam. That is not a very strong base for the 2 inches of concrete on top, and I bet the top concrete would be full of cracks in no time due to different expansion rates of the two concrete slabs.

If you use plywood, you need to use treated plywood or the concrete will destroy the plywood in a few years

 

[yooperman]

I don't think I would tear out the entire floor. I would do like the post above and use reflective foil foam. They make a plywood routed to take pex but like the previous said use a router yourself and a little time and you'll have it. Your thresholds and 1st riser height on stairs will change but thats a small price to have a whole new livable area. And yes if its not real cold out I open the basement door and put a small fan blowing up to heat the house out of the basement.

 

[mga]

i think the plywood made for the PEX flooring system does, in fact, have the channels in them, but i thought the back side of them was an aluminum barrier?

that way they can be placed over the slab and secured with a barrier between them.

 

[mjs97]

do you think the concrete help with efficiency as a big thermal mass or would plywood do same thing. concrete more mass obviously. will main floor heat easier also because of heat radiants up thru floor?

any idea on cost of materials, extra pumps needed for each zone, special valves, not sure what i need i guess. i'm sure nothing is cheap.

thanks,
matt

 

[HUSKYMAN]

do you think the concrete help with efficiency as a big thermal mass or would plywood do same thing. concrete more mass obviously. will main floor heat easier also because of heat radiants up thru floor?

any idea on cost of materials, extra pumps needed for each zone, special valves, not sure what i need i guess. i'm sure nothing is cheap.

thanks,
matt

Yes it will help a ton, in floor heat is just amazing. I am heating a 32x48x6" thick slab of concrete in my barn and with minimal insulation it keeps my barn 65-70 degrees all the time.

Keep your runs of 1/2" pex to 250' or less. You will probably only need one pump for the basement as long as your boiler isnt too far away. How you control the temp in the floor is up to you, there are many different ways.

I just use a mixing valve and custom manifold, and have about $500 into it including the pump. If you get one of those fancy setups it will be well over $1000.

How far is the boiler from the house?

 

[ericjeeper]

I assume you are using a fan coil now?

I would add a valve to divert the water to the floor After the Heat exchanger. That way the fan will have pulled some of the heat off of it.You will likely only need about 100-110 degrees to heat the slab.
Make sure you get a good 2 inches of perimeter insulation between the wall and the new 2 inch topcoat. Pour the slab 2 inches thick., Using 6x6x10 wire reinforcing. Tie the tubing to the mesh. No runs over 250 feet in length. It is going to take roughly 1 foot of tubing per square foot of floor space.
Basically you will have a 1 inch diverter valve cut in to your existing return to boiler lineset, and a tee back in for the inslab return.
I have a home with 3200 square feet of in slab heat and I love it.. Could not imagine forced air heat again.

 

[abohac]

mjs97

i have recently remodeled older house and am now heating it with owb with exchanger in furnace. now getting ready to finish basement and wondering about putting in floor heat in. could i put 1" insulation down, then pex tubing, and then pour new slab 2" thick over it. don't know if this work orshould i take entire existing floor out and pour whole new floor.

i have heard in floor heat is very nice, and will help heat entire house by having it in basement floor. true?

any help is appreciated,
matt

I have in-floor throught my house and I love it (especially in the basement and garage). I'm not sure about what you are going to do. I think you should get ahold of a cement contractor an see what he thinks. If you can do it, by all means put it in.

 

[abohac]

Huskyman

Yes it will help a ton, in floor heat is just amazing. I am heating a 32x48x6" thick slab of concrete in my barn and with minimal insulation it keeps my barn 65-70 degrees all the time.

Keep your runs of 1/2" pex to 250' or less. You will probably only need one pump for the basement as long as your boiler isnt too far away. How you control the temp in the floor is up to you, there are many different ways.

I just use a mixing valve and custom manifold, and have about $500 into it including the pump. If you get one of those fancy setups it will be well over $1000.

How far is the boiler from the house?

You sound like you have a system just about like ours. 371/2 x 60 Morton building (farm shop with a 6" slab). Absolutley a great place to work in the winter>

 

[HUSKYMAN]

I would add a valve to divert the water to the floor After the Heat exchanger. That way the fan will have pulled some of the heat off of it.You will likely only need about 100-110 degrees to heat the slab.
Make sure you get a good 2 inches of perimeter insulation between the wall and the new 2 inch topcoat. Pour the slab 2 inches thick., Using 6x6x10 wire reinforcing. Tie the tubing to the mesh. No runs over 250 feet in length. It is going to take roughly 1 foot of tubing per square foot of floor space.
Basically you will have a 1 inch diverter valve cut in to your existing return to boiler lineset, and a tee back in for the inslab return.
I have a home with 3200 square feet of in slab heat and I love it.. Could not imagine forced air heat again.

I dont think he would need the floor quite that warm, I keep the water coming into my barn at 80 degrees, 85 max.

With this setup do you think one pump will be sufficient? Even if you need a bigger pump it would be cheaper than running another set of lines to the house from the boiler, unless the boiler is very close to the house

 

[HUSKYMAN]

You sound like you have a system just about like ours. 371/2 x 60 Morton building (farm shop with a 6" slab). Absolutley a great place to work in the winter>

Did you bring the heat into the barn in the middle of the slab with that long of a run (60')?

Mine lines come in from the corner, but I dont think it would work as well in a bigger building.

 

[ericjeeper]

Unless he puts in a mixing valve

I dont think he would need the floor quite that warm, I keep the water coming into my barn at 80 degrees, 85 max.

With this setup do you think one pump will be sufficient? Even if you need a bigger pump it would be cheaper than running another set of lines to the house from the boiler, unless the boiler is very close to the house

He is not going to have any low temp water. Yes one pump should be able to push through the heat exchanger and then through the slab.
Does your barn slab see a continual load being pushed through it? Or is it on a stat? He could use a simple wall stat and that could control the zone valve to the floor heat.

 

[HUSKYMAN]

Floor setup

My manifold and mixing valve

 

[HUSKYMAN]

He is not going to have any low temp water. Yes one pump should be able to push through the heat exchanger and then through the slab.
Does your barn slab see a continual load being pushed through it? Or is it on a stat? He could use a simple wall stat and that could control the zone valve to the floor heat.

Just continuous load. Its simpler and the pumps use very little electricity. Supposedly the pumps last longer on continuous use also but I have no proof of that

 

[mjs97]

boiler sits about 60 ft from house, and only 20 ft. from garage. i run loop from stove to garage (inside along wall), to house (attached), thur side arm on water heater, thur coil in furnace, back to garage thur radiator setup(with fan on thermostat), then back to boiler. currently have no in floor heat.

one concern is if i pull water after coil in furnace its still probably 150 degrees, or is that when valve would open and shut when calling for heat.

one bedroom will be down stairs, should that be seperate zone with seperate thermostat.

you think wire mesh in cement will keep it form cracking if i put 1" foam down then pour cement over it 2" thick. otherwise probably be better to use foam and plywood method.

thanks a ton for the info,
matt

 

[yooperman]

Huskyman, I was just curious if that was 5/8" pex in your barn?

 

[500kcmil]

huskyman, what size pump are you running?

 

[HUSKYMAN]

Thats 1/2" pex in the floor. The pump is a smaller Taco, but I dont know the number. I will post the number a little later.

Matt you need a mixing valve or some other device to lower the temperature of the water before it goes into the concrete. I dont know the answer to insulating your concrete but I know you cant use foam as a base, its not solid enough.

How about this as an idea---build a frame out of 2x4's on 16" centers and use foam insulationin between the studs. Then run your pex tube along the studs and put 3/4" OSB flooring over the top. Then you can run your tube at a full 160 degrees and you will get a ton of heat in the basement.

 

[abohac]

Huskyman

Did you bring the heat into the barn in the middle of the slab with that long of a run (60')?

Mine lines come in from the corner, but I dont think it would work as well in a bigger building.

Nope. I ran the lines to the center of the building and ran them the 371/2 way so that the runs were not long. Plus, I laid out half the building, poured half the cement (so i could have the truck drive in) then did the other half. I do have some trouble with the stove overheating some time as the stove is only 10 ft from the shed. Works great.