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pointingdogsrule
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Posts:3
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| 01/23/2004 7:55 PM |
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Hi Guys and Gals;
I am making an OLD 33 x 60 foot, straight roof barn (which is in good shape) into a house. All the living area will be in the "hay mow" (upstairs). The peak is 28 feet above the floor. I have lofts 8 feet above the main floor and these will serve as bedrooms and a loft area. The roof is insulated from the outside with Icynene foam insulation and covered with metal. The walls are also insulated with Icynene. I have an approximate R-28 value in the roof and wall insulation.
My problem lies with the floor. The basement where the cows were housed has too many posts (supports) to make it a "livable and functional" area. The 80% of the basement that is not finished off will NOT BE HEATED. The "hay mow" floor is very stable, however, when they built these structures in the early 1900's they were not that all concerned with a "LEVEL FLOOR". My plan was the level the floor as close as possible then cover the floor the 2 - 3 1/2 inches of hard foam panels (minimum R-7.5). NOTE: the 1 1/2 inch difference in foam thickness is the difference in the highest and lowest points in the floor. The tubing would then be stapled to the foam and a layer of GYPCRETE (THERMAFLOOR) poured over the tubling. The self-leveling GYPCRETE would be ideal to give me a level floor. And the radiant floor heat ideal to heat this large high area!!
Question 1; how much "R" do I need under this floor to force the heat into the slab of GYPCRETE (or prevent loss of heat downwards)??? Is the R-7.5 enough, over that unfinished basement??? NOTE; I live in Iowa where it gets quite cold in the winter.
Question 2; This may be a very STUPID question, I was planning on putting radiant heat in the above lofts also (bedrooms). Will a foil under the gypcrete be enough to reflect the heat into the slab considering the area directly below is already heated???
Thanks to all in advance
doc marty |
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Unregistered
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| 01/23/2004 8:21 PM |
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Over an unconditoned space, a minimum of R-25 is a very good idea. Insulation does nothing to force heat into the room above. It's sole purpose is to slow the downward loss to a cold area.
Can you just pour gyp over the existing floor once all of the cracks and holes are sealed to level the floor? Or, do you need to raise floor heights that much? Extruded polystyrene, which is what you would put over the floor has an R value of 5 per inch thickness. If you are going to do this, pick the insualtion with the highest compression ratio. It will be a more stable floor and minimize deflection. Remember that gypsum based overlayments are not a wearable surface and must have a finished floor over it.
Aluminum foil under the gyp will not "reflect" energy and because it is in direct contact with the slab, and may actually wick heat away since it is a good conducter.
Warm Regards,
hb
www.climatecadvanced.com/installation/New/new.html
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pointingdogsrule
Registered Users
Posts:3
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| 01/24/2004 9:16 AM |
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Hi Heatboy!!
Thank you very much for your response. Yes, I could pour the entire floor with gypcrete and insulate the underside with Icynene. My one concern is the additional $$$ of the extra gypcrete thickness. If I remember 1 1/2 inches is about $2.75 per sq. ft. I could only imagine what 2 1/2 to 3 inches (only in some areas) would cost. The difference between the highest and lowest point in the barn floor is 1". As far as, the floor goes ... they now have a product that coats the gycrete (actually THERMAFLOOR) and enables one to walk on the surface.
What would you suggest that I put under the tubing and gypcrete in the lofts (bedrooms), if anything? Currently it is just a plywood floor.
Heatboy!!! Thank you very much for your response. It is very much appreciated!! Hope to talk to you in the future.
doc marty |
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Unregistered
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Posts:2321
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| 01/24/2004 7:27 PM |
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While it will certainly cost extra for the additional gypcrete, it may not be the bank breaker you think. Since you are paying for the crew and materials to actually show up, the increase in materials may not be much more than buying all of the polystyrene you would need. Well, not quite, but you get the point. The sealer, I believe, you are referring to semi-waterproofs the Thermafloor, but it isn't a wearable surface. It can be walked on, just not lived on. ThermaFloor is the highest quality gypsum based overlayment I have seen, but the quality entirely depends on the guys actually mixing and pumping. I have had a few less than stellar pours (not Therma-loor) over the years that have cost me time and money to make right.
Nothing is needed on the sub-floor before a gypsum based pour. The crew will spray a latex based liquid that is supposed keep the tube in contact with the tube upon drying. The gyp shrinks when it dries and the latex keeps the gyp from shrinking away from the tube. Heat transfer efficiency would be diminished if the gyp pulled away from the tube and allowed an air gap to form around the tube.
The other option, and possibly a better one, would be a lightweight concrete. Should be less money with more availability. I have a recipe somewhere for Youker's mix which is was used for the early radiant projects back in the 60's. Here is an article from Plumbing & Mechanical. http://www.pmmag.com/CDA/ArticleInformation/features/BNP__Features__Item/0,2379,5590,00.html
I'll bet you didn't know that concrete is twice as conductive as gypsum based materials. That's one of the primary reasons concrete radiant run much lower water temps than anything else. And, concrete is a wearable surface.
What is your finished floor going to be?
hb
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Unregistered
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Posts:2321
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| 01/26/2004 10:31 PM |
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For your loft living floor I would suggest Warmboard or something similar instead of Gypcrete
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pointingdogsrule
Registered Users
Posts:3
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| 02/03/2004 11:45 PM |
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Hey Heatboy!!!
Thanks for all of your help. Sometimes after looking at a project for such a long time and banging my head against the wall things become unclear. You gave me plenty to think about. I decided to call the THERMAFLOOR people and ask them what the additional cost would be of adding more THERMAFLOOR to the low spots (note according to my calculations ... $2,000 more) and they stated only $600 to $900. Difference in $$$ was due to thier set-up costs and additional material was cheaper once they were set-up. I have also decided to insulate under the floor with Icynene to an R-28 value.
Once more, I VERY MUCH APPRECIATE ALL OF YOUR INPUT AND HELP.
doc marty |
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