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mlennox
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| 03/05/2009 7:26 AM |
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Posted By Brawler on 03/05/2009 6:27 AM
Thanks for the reply Dan, How thick do you typically pour LW Concrete and what do you put between the concrete and subfloor? I am planning on putting down 6mil poly. Thanks again, michael
I'm also curious about what goes between the subfloor (OSB or plywood) and the poured floor (concrete or gypcrete). I've heard everything from putting nothing down between them, putting down 6 mil poly, putting 2 inch EPS foam, and putting both 6 mil ply and 2 inch EPS foam.
What are the pros and cons of each, and what is really required from a functional point of view? Presumably with the poly layer you will be stapling the radiant tubing down to the subfloor such that the staples will penetrate the poly; is this a problem?
Thanks.
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jmagill
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| 03/05/2009 7:33 AM |
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Posted By mlennox on 03/05/2009 7:26 AM
Posted By Brawler on 03/05/2009 6:27 AM
Thanks for the reply Dan, How thick do you typically pour LW Concrete and what do you put between the concrete and subfloor? I am planning on putting down 6mil poly. Thanks again, michael[/quote]
I'm also curious about what goes between the subfloor (OSB or plywood) and the poured floor (concrete or gypcrete). I've heard everything from putting nothing down between them, putting down 6 mil poly, putting 2 inch EPS foam, and putting both 6 mil ply and 2 inch EPS foam.
What are the pros and cons of each, and what is really required from a functional point of view? Presumably with the poly layer you will be stapling the radiant tubing down to the subfloor such that the staples will penetrate the poly; is this a problem?
Thanks.
We put poly on the subfloor. My understanding is that the poly is so the concrete does not adher to the plywood. This helps with cracking due to building movement. |
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Blueridge company
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| 03/05/2009 10:21 AM |
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Most applications are 1 1/2 inch, generally a double plat under all walls. No need for plastic, or pressure treated wood on platforms that are not in contact with earth or perimeter foundation. there will be a top plate on the perimeter foundation of treated wood as your standard bug/rot barrier. Once the topping pour is dry there will never be moisture again unless you have a leak. If anything we will spray lightly the plywood with water to help topping pour stick and not kick of to quickly. your flat worker and pump man will know what to do.
Dan |
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jimmy48
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| 03/05/2009 11:32 AM |
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| poured directly on my floor no poly no foam |
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Brawler
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| 03/05/2009 11:40 AM |
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| Dan, What would you recomend to do where i plan to place interior non load bearing walls? Is it possible to just glue down bottomplates for the wall or must they be nailed to the concrete. The walls above this floor will be 6" sips, sitting on the subfloor. Should i place anything between the sip and concrete. I plan on pouring and tubing the entire floor to allow for possible future changes of use. Thanks, michael |
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jimmy48
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| 03/05/2009 5:19 PM |
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| you should double plate all your walls the concrete will come up to the top of the ist plate |
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Blueridge company
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| 03/07/2009 12:58 PM |
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In most applications all the walls are usually in place prior to lite weight or gype crete, Pipe is held 6 inches from all walls, and where ever possible path threw the doorways, If a wall is breeched for pipe it is noted on the master plans of the house. Sounds like you are doing a shell first and then infill walls to have options. so caution on electrical and plumbing, don't want to drill down on a pipe. Certainly can use liquid nails, a short pin (thick like joist hanger nails, concrete nails) in the cement (1/2) will add considerable shear value to hold the wall in place. Again, you may also consider some blocking on the floor in the places where the future walls will go to have safe fastening/drill points. Blocking is also a solution for the electrician to add floor outlets to a radiant platform. When we install we like to arrive after the plumber, ahead of the electrician, so block outs make his work easier.
Dan |
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Brawler
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| 03/07/2009 7:51 PM |
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| Thanks Dan, that is exactly what im doing. So i can just pour right up against the sips or should i install ledger boards or something. Thanks |
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fullhouse
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| 05/01/2009 1:52 PM |
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http://www.maxxon.com/brochures/Therma-Floor_Comparison_Guide_4-08.pdf
here is link to a comparison guide, Maxxon's "Therma Floor" for radiant heat applications vs. various other products.
Therma Floor is poured before or after drywall, and directly on your subfloor. It won't shrink/crack like concrete, and if there is cause for concern of cracking due to structural movement Mer-krete offers an anti-fracture membrane which will address this. There is also a guarantee, when used in conjunction with Maxxon's products.
Acoustical Floors is located in Oakville, ON, and performs installations across Ontario. Licensed installer of ALL Maxxon underlayments. www.pouriton.ca, or 905-827-6358. |
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Blueridge company
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| 05/01/2009 4:50 PM |
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If you are using a light weight cement and doing your own work a ledger 1 1/2 x 1 1/2 would be handy, if you are good a red chalk line will work. A professional will use a snap line. Gype crete will self level and be poured by a pro they will have there system..
Dan |
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BadgerBoilerMN
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| 05/18/2009 9:08 AM |
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Gypsum based cementious flooring products and "lightweight" concrete should employ crack barriers. Some concrete applicators are not familiar with this type of "thin pour" so attention to detail is critical.
It should be noted that many "light weight" concretes employ fillers (to make them “light”), which are also pretty good insulators; counterproductive to an efficient radiant panel, potentially affecting output and performance.
Maxxon was the pioneer (and still master) in this particular technology.
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MA
www.badgerboilerservice.com |
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mlennox
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| 05/18/2009 9:24 AM |
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In preparing a floor for a Maxxon Therma-Floor poured over radiant tubing, I understand that I will need double 2x4 plates, with the first plate acting as a backstop for the cementious mix. What do I do at stair openings or split level floor edges? Presumably I will nail a single 2x4 layer at the edges (essentially a single plate)?
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BadgerBoilerMN
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| 05/18/2009 9:50 AM |
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| Your are correct. But your applicator or system designer should be answering your questions as it is he you will depend on for the final product. |
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MA
www.badgerboilerservice.com |
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jonr
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| 05/18/2009 9:52 AM |
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I would look into hardibacker over gypcrete - stronger, better bond.
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BadgerBoilerMN
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| 05/18/2009 10:01 AM |
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| I don't remember Maxxon recommending hardibacker? |
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MA
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Blueridge company
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| 05/18/2009 10:51 AM |
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I have had poured for my company over the years several hundred thousand feet of "light weight cement". It is not rocket science.
A few points.
1) it is not light, about 17 lbs per 1 1/2 inch thick square foot.
2) standard mix for the 2 inch line pump is 7 1/2 sack Portland cement, pea gravel, sand, dish soap to make it slippery (not a lot) and 1 sack fiber glass strands as binder per yard. Your pump operator and finish workers will know the recipe that works best for there crew, location and equipment.
The mix is similar a slab on grade, heat transfer and storage are the same as concrete.
Cracks will occur, if the slab is to be finished for acid wash or whatever surface plan on 2 1/2 inch minimum, scoring control joints on all corners and still you will have cracks. I have seen folks come back with concrete cutter while concrete is still green and cut a 2 foot x 2 foot grid, and a 4 foot x 4 foot grid. this helps with cracking but cracks happen. (the grid does make an attractive pattern to an inexpensive slab floor).
one thing that helps bind the pour to the ply substrate is a light spray prior to pour.
Forget plastic, or tar paper, unnessary and if you heat to quickly the concrete will "curl " on the cracks making raised edges of about an 1/8 inch.
Advantages to light weight cement over gyp is that on smaller pours (2,500 sq ft ) the cost is substantially less. In these parts placed light weight (material and labor, contracted) is about $1.25 sq ft. The site equipment is less ( a 2 inch line pump and competent flat worker team.
Further Tile can be placed directly after cement cures. Though high end pros will want a floating tile membrane as crack transfer insurance.
Plan on 2x2 blocking on all open to stair type edges, around the kitchen island, 2x6 blocking for floor electrical fixtures, toilets, so on. pay close attention to finish surface where sheet goods or floating floors will be applied, if traditional nail down floors are being placed plan on 2x4 12" pattern flat screwed an glued and infill with cement. Some guys use 2x2 but your floor man will be applicative of a 2x4, better target for the nailer, no wood where pipe crosses over the 2x4 lines, rule to the floor guy is nail only where there is wood.
bottom line about cracks is they will occur, they have little effect on the pipe, I have systems that are 20 years old like this with out issues.
Good luck, Hire a pro to place your cement, it is not fun by hand over about 400 square feet.
Dan
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Brawler
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| 05/18/2009 12:28 PM |
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| Since my last post i have installed my trusses, !4 inchers on 12' center. I decked it with Advantec 3/4 and i will soon be ordering the 6 inch sips. If i was to put down a double plate i think the bottom plate would have to be bigger than the one that the SIPS will fit over so the osb is supported. I was thinking about a 2x8 below a 2x6with the 2x8 set 7/8 inch further to the exterior which would leave the 2x8 over an inch proud of the sips interior osb, or just installing a 2x2 around the interior of the sips against the floor. Less wood and better insullationsince there would be less direct wood bridging, interior to exterior. I cant help thinking the poly under the pour would help slow the cure and keep the crete from adhering to the subfloor. Wouldnt both of those things help with cracking. My crete supplier has talked me into full weight concrete engineered more strongly with fiber. The dif in weight is minimal and we desighed the floor strong enough. A seperate issue is the 18' travertine we were given and plan to use in the "not so" great room. What is the best way to prevent the cracks that are going to occur from transfering through the travertine. the space involved alltogether is about 465' feet downstairs and 277 up in the loft. As always all advise greatly appreciated. |
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jonr
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| 05/18/2009 2:26 PM |
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I agree about plastic to decouple the concrete from the plywood. I would look into Schluter Ditra or hardibacker to prevent reflection cracking.
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Blueridge company
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| 05/18/2009 3:34 PM |
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Have ether one of you had experience doing concrete work? Thin (1 1/2 inch pours)? De couple?what??? you want attachment to the ply. As I said earlier a light mist will help the ply/cement attach.
If you want a crack free self leveling pour get gyp crete. If you want to nurse the situation you possibly could mist the floor after the cement kicks and you can walk on it to slow the dry time. Burt I have only seen this done on thicker (4+ inch) flat work. Talk to the fellow you hire with the line pump and flat work crew. If your work requires a slip joint for the tile to cement bond you will want a product like:
(DUROCK™ tile membrane is an easy-to-install, thin, waterproof, and vapor-permeable underlayment and tile backer for use in residential and light-commercial floor and wall applications. Available in roll form, its superior tile bond (a result of its patented cementitious surface) provides lightweight, panel-like performance).
The beauty of cut and paste.
Good luck with your project,
Dan |
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jmagill
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| 05/18/2009 3:37 PM |
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Posted By Blueridge company on 05/18/2009 3:34 PM
Have ether one of you had experience doing concrete work? Thin (1 1/2 inch pours)? De couple?what??? you want attachment to the ply. As I said earlier a light mist will help the ply attach.
If you want a crack free self leveling pour get gyp crete. If you want to nurse the situation you possibly could mist the floor after the cement kicks and you can walk on it to slow the dry time. Burt I have only seen this done on thicker (4+ inch) flat work. Talk to the fellow you hire with the line pump and flat work crew. If your work requires a slip joint for the tile to dement bond you will want a product like:
(DUROCK™ tile membrane is an easy-to-install, thin, waterproof, and vapor-permeable underlayment and tile backer for use in residential and light-commercial floor and wall applications. Available in roll form, its superior tile bond (a result of its patented cementitious surface) provides lightweight, panel-like performance).
The beauty of cut and paste.
Good luck with your project,
Dan
Can you explain why you would want attachment? |
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