underslab inuslation

Kal Row

Kal Row

re siggi's underslab insulation artical...

re: http://www.pmmag.com/CDA/Articles/Column/BNP_GUID_9-5-2006_A_10000000000000372298

siggi's article on underslab insulation in the radiant and hydronics news letter was right on, it's even worse in a warehouse freezer where freezing underground will undulate
the floor making huge sections unusable by the lift trucks - the right way is 20" excavation, 3" of course gravel, grid and pex heating tubes (1"), 4" base concrete, 4" extruded foam, then 8" of reinforced concrete = 20" tot - this setup keeps the ground from freezing and wrecking your whole warehouse freezer, but when you tell people those numbers they freek!!!!

even in a house, conveying it to customers, is, like dan says, "explaining clouds to fish",

i am always fighting with the customers for every inch of insulation, their belief system is just not there!!!, just try showing siggi's formula to even the most math savy customer and watch their eyes glaze over, i usually have to settle for "insultarp" + bubbble wrap - .5" and r12.5 total,

the people that install pavers, really get bent out of shape because thier pavers get out of vertical alignment when the heat is off or uneven - people cheap out on slab idling and then all hell breaks loose

perhaps Dan Holohan can come up with a humorous way to "splain" it to them

Jim_139

What?

I thought heat always went up? Throw enough heat at it and it's bound to work. Kind of, maybe a little?

Unknown

if you have problem...

If u have problem exsplaining to these people.. Then send them to ice rink contractors... that'll convinced them..

Brstr

Heat

Hot air rises, heat radiates.

Wayco Wayne_2

Bruce

I think Jim was being sarcastic. D'oh.

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Kal Row

When people tell me that heat rises…

I just look at them and say…”ahh so that’s why the earth is so warm, it’s because we are 90million miles above the sun and the heat rises across 93million cold, black, empty miles of space to heat us”….you can almost see the gears start to turn in their heads, - the next thing I do is quickly put my palm 1 inch of their forehead and say… “feel that?, how come?, I didn’t touch you, and my hand wasn’t there long enough for the heat to conduct across the air space”…”that’s radiant heat!!!”

Kal Row

hmmmnn...

wonder how many zamboni's have overturned from going into an earth-freeze induced concrete spall - and just imagine it spalling just as a skater goes over it, whoah - can i be the lawyer, - it's even worse with wharehouse freezers, as the inner temps are -20, and a forklift with a palet of frozen meat weighs a tad more - my dawghter works in a wherehouse whose freezer has a 15 inch vertical spall - redering that area unusable - i offerd to do a 30x30 area as paid test - but the owner wont go for the expense, he will just chop it out and pour some new crete...

that formula BTW, was published in one of our recent trade magazines - i cant remember which, i read so many

Mike Dunn

underslab insulation question

Let's say I have a 60,000 square foot square building with a 25 btu per sq ft heat loss. That's 1.5 million btu's.

Let's say that 75% of the heat loss is around the perimeter and 25% in the middle. That 25% comes to 375,000 btu's.

Let's also say we've used 2" of rigid foam down 4 feet of perimeter frost wall and out 12' into the building. That leaves approx 48,800 sq ft of floor with no underslab insulation.

I want to know if there is a way to figure out how many of those 375,000 btu's are going down before going up?

Unknown

how are you getting r12.5 from insulation products rated for R1.65 ?

Unknown

ah, but neither are. all you ever wanted to know:

http://www.healthyheating.com/Page 55/Page_55_o_bldg_sys.htm

tomk_2

underslab insulation

www.crete-heat.com

Kal Row

so i am screwed, blued, and tatooed...

i hate it when a cheap ho screws an otherwise perfect job!, now i am doing one where the ho is on board, an going along with 2" gravel, 2" foam, 4" of pavers - this one will be nice

Larry Weingarten

Kal, I like to...

... have people look at insulation and dollars two ways. The usual way is first cost, or "Who gives me the cheapest bid now?" way. The other way is life cycle cost or "What saves me the most dollars in the long run?" way. A way to get this across is to suggest the building you're building now is going to last at least fifty years, right? OK, how much is energy going to cost in 25 years? If you insulate to that level, you're at break even on energy for the building. If you only insulate to what's cost effective today, you're out of date next week, energy-wise. I know most folks are not going to hold onto property all those years, but the building is worth more on resale with superior insulation and the energy bills to prove it. We really have not been brought up to look at the long term and that is a barrier we need to overcome to become energy efficient.

Yours, Larry

Evil lution

Frozen food warehouse

I was a manager for a frozen food warehouse for 10 years. We had a problem with up lift in our 35,000 sq ft warehouse and came up with one of the cheapest soultion I have found yet.
Instead of digging up you floor and starting from new, we hired a company to core holes across the foundation. On a 3foot thick slab the bottom 1 foot they drilled a 1" hole from East to West 1 foot apart across the foundation. It worked. With the outside air always being warmer than 20 below eventually the slab thawed and resettled. It's expensive but it works. It dosen't stop production in the warehouse.
Food for thought. It's not piping but it's a solution for you customer.