foamboard along walls

[Dave Maxwell]

I read somewhere and now can't find it. Search isn't working on my phone for some reason tonight. How far down from top of floor do I need to put the foam board? Its 2 inch foamboard. 5 inch heated floor. I thought I read it should be 2 feet. Thanks

 

[lzenglish]

The Laws of thermodynamics state: Heat Rises, and Always flows from Hot to Cold. So, given that, I would add as much insulation as possible, from the ground level to ceiling. Just think of a "Thermos Bottle", and or Cave, as an Example of Retaining Heat, and or Cold, (which is defined as the absence of heat). This is one case that I know of, that "The Bigger the Glob, the Better the Job", actually applys!

Wayne

PS: I know of a person in town that used 2 inch foam board on his roof, and reduced his bill to 15 bucks a year, along with ALL the other several energy savings devices he used. This Guy had a Plenum House, and used the cool slab crawl space to cool his house, with a whole house fan! If you want more info, PM me.

Wayne

 

[Dave Maxwell]

I'm insulating all the way up. Just not sure how far below concrete I need to go. Will have two inch under it. How far down vertical is what I'm not sure of

 

[lzenglish]

I would not go down below the concrete slab myself, but, it would surley not hurt, if you did. Like I said, the more insulation you have, the Less heat load you will be dealing with!

Wayne

 

[Dave Maxwell]

Thanks

 

[Dave Maxwell]

Since in Puting fiberglass rolls in the walls. Do I need yo bring the foam board up past top of floor. Staring it in the morning

 

[oilslick]

I am putting 2" foam 2' down around my pole shed. I am not using in floor heat but figure it might help keep the frost out!

 

[D.J.]

If it was mine, I'd put it 2' verticle on the perimeter of the slab.

 

[stingry]

Since in Puting fiberglass rolls in the walls. Do I need yo bring the foam board up past top of floor. Staring it in the morning

NO, just put the EPS down as deep as the footings, usually 2'. Sure, in theory, deeper would be better but at some point practicality trumps theory.

Cheers
Steve

 

[aar_man]

Dave,
I've done this with both of my buildings...if it isn't too late send me an email at [email protected]....I can help.

John

 

[Highbeam]

You're dealing with two different issues. One is insulation to keep your slab heat in and the other is frost heave. You don't want the frozen ground under the edges of your slab.

Since I don't have a frost heave issue, I only put vertical foam down on the sides of the slab to the bottom of the under-slab foam.

Meaning, flat compacted subgrade, then plastic up to and over the forms, then side foam from top of form to top of plastic, then under the slab foam butted up to the side foam. Then mesh, then pex, etc.

The side foam will be 7" tall. I'm not digging out to bury foam, instead, wrapping the entire slab with foam.

No frost issue on the west side.

 

[Dave Maxwell]

I'm puting the foam board 2 feet down from top of floor and seaming it to the foamboard that is 5 inches below top

 

[Dave Maxwell]

 

[jack stand]

I read somewhere and now can't find it. Search isn't working on my phone for some reason tonight. How far down from top of floor do I need to put the foam board? Its 2 inch foamboard. 5 inch heated floor. I thought I read it should be 2 feet. Thanks

Idealy, insulate down to your local frost depth.

 

[wedge40]

Dave a couple of questions.
I'm curious about the plastic behind the FB? How was that placed?
Also where did you get your FB?

Wedge

 

[Dave Maxwell]

The plastic was cut long and I draped it like a curtain. Then just stapled it to the splashboard. Foam came from menards.

 

[50cal]

Down to your frost depth would probably be plenty. I would add some if your slab is raised above surrounding area. If it comes out more than 24 inches, it wouldnt hurt anything to go the full 48 inches.
http://www.sqfoot.com/pdf/US_Map_Frost_DepthAVG.pdf

 

[Dave Maxwell]

I went two foot. I hope its enough. Had been told frost around here only gets to two foot on occasion

 

[oilslick]

Any updates or pics of progress?

 

[Dave Maxwell]

Got almost all the foam board in. The rocks and stuff slowed digging alot. Then backfilling with a wheel barrow is taking forever

 

[Dave Maxwell]

do I need the sides and face of the post like in the pic. Sides are 2 foot deep. Front is 7 inches which is bottom of floor foamboard

 

[Dave Maxwell]

Well I hope it was needed. I did it and actually lowered the front piece also. 30 poles takes awhile. Lol

 

[NUTTSGT]

Right or wrong I don't know Dave but I would have done it that way. In the very least I would think it would create some type of thermal break between the heat leaving and the cold entering. . . . I guess that's what insulation is supposed to do.

 

[Dave Maxwell]

Figured the wood DD some isolating.
Then put a small piece on the front to isolate the wood from the concrete
Man do I need to hook my computer up. Phone and its auto correct