The Combine Forum banner

21 - 40 of 53 Posts

·
Registered
Joined
·
842 Posts
We are planning on having a heated floor running PEX every foot on top of 2 inch high density foam and 15 mm rebar at 12 in if I do spray foam it'll be two or three in and probably R-20 bats walls are 2 by 8 construction.

Like the idea of running drainage tile out a side hill but worried that mice or rats me use it as an entry way

Thought about running foam between the strapping on the outside but it would be a bit of a job now that the tin is already done could possibly pull the corners off or a couple of sheets and slide foam between the two by four strapping. Will have to look into this.
Had a mechanical company design my floor heat in my shop. They recommended to put tie the PEX above the rebar closer to the top of the slab, rather than the bottom of it. Reason being it makes for a more efficient heat transfer into the shop. Cement guys don't like it as they have to be more careful when working the concrete, but it is your shop. Don't forget to put a vapour barrier underneath the insulation as well. My shop heats very efficiently and I really like the floor heat.
 

·
Premium Member
Joined
·
5,266 Posts
When you buy styverfoam for the floor make sure it is rigid enough or has the right compressive rating that it will not crush easily. The two inch lowes silver board has a very high compressive rating and is the vapor barrier if you tape the seams. How are you insulating your grade beam? And exposed couple feet of concrete on the grade beam can loose as much heat as the whole building above it if not insulated. It is not hard to lay the heat pex pipe if you understand the rules on how it is done. We paid for a pex drawing but it is a waste of time if you understand the basics of how to do it. In our garage we installed a 600 cfm fan in the peak of the scissior trust and duct it to the eave with 20x6 inch rectangular galvanized ducts.
 

·
Registered
Joined
·
1,425 Posts
Discussion Starter #23 (Edited)
Grade beam is insulated with two inches of foam on the outside and not sure if Ishould insulate the inside of the grade beam.Looking at using 2” of Plastipan 40 which has a rating of 40psi. As far as the pex I have already drawn myplan but not sure if I should staple to foam or tie to rebar. Still have to buy my pex, who has the best prices out there?
 

·
Registered
Joined
·
793 Posts
The 24" horizontal Styrofoam keeps the ground below concrete above freezing, prevents frost heaves, cracking. Your piles should prevent all the frost jacking happening to most post frames around here. Rare to see eaves and gables too, we did a foot all around. You have 24" OC studs and rafters, very strong.
 

·
Premium Member
Joined
·
5,266 Posts
The 2 inch silver board has a psi rating around 40-45psi. Your 40 should be good. The silver board is around $36.50 per 4x8 sheet when Lowes has a 15% discount. For pex we bought the vega floor heat 1/2 inch pex last fall for $.31 per foot. The 1/2 inch mainifolds were $200-300 depending on the number of loops.
 

·
Registered
Joined
·
218 Posts
Definitely staple the pex heat pipes to the foam!!!
I have done both (staple or tie to re-bar/wire mesh) and since I bought/use the stapler it takes half as long to do a floor and no sore back, knees etc.
My daughter was 11 when her and I did the pipes in our 1600sqft garage.
Took just under 3 hours for the 2 of us to layout and fully staple the pipes.
A trough floor drain and large landing to work around cost us an extra hour.
Have done a couple 40x60 to 60x120 since with 3 and 4 guys and adjusting the plan on the fly to work around drains etc and takes 3 to 6 hours.
I try and get 1200ft rolls and only use 1/2" pex.
I want a decent pex unroller if/when I do another floor.
 

·
Registered
Joined
·
459 Posts
Looks sharp!
Do a good floor drain system, I can't imagine not being able to wash something inside in the winter and your from Canada! Don't fool yourself!

Even if your not doing floor heat I would consider doing insulation under the floor, you wouldn't believe how much heat is lost through the floor.
AGREE 100%, have two heated and both have insulated floors and a sump (trucks in winter thawing etc), plumb it right put a washroom and laundry rough in at least. Pipe the floors we hooked only one up but it gives you opion, if nothing it holds 300 psi ,run compressed air to spots
 

·
Registered
Joined
·
1,855 Posts
My floor is double rebar thickened edge slab with 6" thick on the rest in floor heat between rebar with 3/8" or 1/2' reflective foam underneath. 2" under slab on top of dirt is way overkill in my mind.

How much heat loss do I have? Haven't put any insulation around perimeter yet. I want some heat loss where I am keeping frost away from under building. The snow won't even melt on an average winter day.

If I was doing it again I'd save money on infloor and put solar panels on the roof.

Put a U-drain in or something very similar, one of the best things I did in mine. Yes it's overpriced, mostly because of the installation. Well worth it for me. My sump is in the middle. With my layout I wouldn't want it anywhere else. I think I could drive a semi loaded over it.

Sprayfoam costs more upfront. Make sure you get the cost of insulating and vapour barrier installed with labor when making your decision. Nothing will seal better than the spray foam in my mind.

A shop will be around a lot longer than your equipment so don't cheep out now.
 

·
Registered
Joined
·
1,425 Posts
Discussion Starter #29
Haven't seen much progress on the shop lately mostly picking up materials to get ready for the pouring of the floor, picked up the foam and pex stapler waiting to put in some weeping tile for my drainage. Had the walls spray foamed with 3 inches of foam we'll also add additional five and a half inches of fiberglass to the walls. My rafters are spaced at 2 feet is there any need to put strapping on or should I just screw the metal to the rafters? Hoping to have the floor poured by July 1st, then start on the interior.
 

Attachments

·
Premium Member
Joined
·
5,266 Posts
Sasksodbuster you will want to zip tie the floor heat pex to the rebar rather than staple it to the styverfoam. I do not see why you would have to strap the rafters. I just sheeted mine with 5/8 fir that was just under $20 a sheet at the time which was far cheaper than metal. You can walk any where you want on the ceiling when in the attic which was nice when I was blowing in my cellulose. Putting metal up on the ceiling would be faster than sheeting with plywood. I really like the painted white plywood on the walls and ceiling. You can mount anything you want on the walls and it is makes the walls very strong with sheeting on the inside and outside.
 

·
Registered
Joined
·
1,425 Posts
Discussion Starter #32
With the price of lumber going up I would not be surprised if metal was cheaper, than again I’m not sure how the tariffs will effect metal.
 

·
Premium Member
Joined
·
5,266 Posts
Lumber has be going up constantly since last summer. I am glad we are almost done with our house. The materials would cost us a lot more right now than what we paid for them.
 

·
Registered
Joined
·
1,425 Posts
Discussion Starter #34 (Edited)
What is the reasoning for tying pex to rebar instead of stapling pex to foamboard? Do you think that you will get a faster response time with thermostat, or that pex on the bottom of slab is inefficient. this is the first heated floor for me, so I'm a newbie to this.
 

·
Premium Member
Joined
·
5,266 Posts
If your pex is under the rebar then it would be fine to stapple. I would still zip tie the loop ends to rebar unless they are right under some rebar. The key is to prevent it from floating up when the cement is poured. Styverfoam has very poor holding power for staples. You want to pressurize the pipes during the pour which causes the pex to want to float up and out of the cement. To pressurize you just put on a gauge and a tire inflation stem type air fitting to blow into and to not leak back. I think it is better for heat transfer to have the pex off the styverfoam and surrounded by some cement on all sides. I also wonder if it is at the styverfoam if it would provide natural crack places for the pad to crack at because of the void created by the pex at the bottom of the pad where you need lots of strength. Having the pex next to the rebar would be my preference for heat transfer and strength.
 

·
Registered
Joined
·
542 Posts
If your zip tying pex to rebar use short zip ties and cut the tails off pain in the a#% finishing concrete and there's a zip tie sticking up.
 

·
Registered
Joined
·
153 Posts
IMG_1983.JPG

Here s another way to do heatlines,no staples,lines won t float,only a few zip ties at the corners maybe.Its used a lot in residential construction.
 

·
Registered
Joined
·
1,425 Posts
Discussion Starter #39
Looked at some of those products like that but most of them had a low psi rating (under 20) and are over priced, I’ve ordered some 40 psi foamboard in 4x8 sheets. We are planning on putting plastic underneath the foam. Foam board is lapped should I be taping the joints?
 
21 - 40 of 53 Posts
Top