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Thanks in advance for any help you may have to offer.
I am getting ready to finish a house I am building. Construction is left in place forms (concrete) with radiant in floor heating on concrete floors (6″ mesh reinforced, 4 to 5″ thick) main and basement.
I want to install hardwood where appropriate. I have been told only a floating floor will do (i.e. Pergo, or hardwood veneer plywood).
Last week I visited a friend who had just moved in to a superbly built house with in floor heating (1″ concrete on plywood) and hardwood floors. His builder told me the flooring subcontractor used quarter sawn 1/2″ oak glued down with sub floor (i.e. polyurethane construction adhesive), and that this worked fine as bond as the concrete was good and dry.
I am tempted to try this but it would be an expensive mistake. If it works it would save me a lot of money, but more importantly give me a great deal of flexibility in terms of special wood borders, etc.
Any comments on this approach? Suggestions, experiences, etc., would be greatly appreciated.
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I'm doing similar, only 8" slab w/ lots of rebar and using bamboo, but essentially the same. Will have cured 1.5 to 2 years before putting down the floor. Thought I'd have to do floating, also. The bamboo supplier said I could easily glue to concrete as long as moisture content is
*Brian, There's a bit of relevant info included in both of these articles. Hope they help...Hardwood Over RadiantHardwood Over Slab
*Hi Jim,Why such a thick slab?Gabe
*I laid a lot of parquet over heated concrete slabs in Australia and the finishing is very important. Because of the rapid changes in moisture content of the timber (from heating off to heating on) and the movement that causes we found it best to use a finish that would allow the timber to breathe so it could recover quicker. I would suspect that this will apply to hardwood flooring as well, although maybe not as much. I used Bostik polyurethane adhesive to cope with the extra movement and had no problems. The big No-No is to use anything like moisture cured poly as a finish because that will edge glue the boards and with the movement you'll have boards splitting.
*I dont really know to much about the radiant part, but all of our houses are slab on grade. Bostik's Best is the ONLY glue to use. IT is excellent..David
*Hi Gabe,>Why such a thick slab?I got a good deal on some concrete?Nah, it's elevated. It clear spans 24' on one side and 21' on the other side of the center beam (a W16 x 100 just for curiosity). And it holds the radiant tube, plumbing, electrical conduit, and two layers of #6/#4 bar mats. Basement is typical 4"-5" slab.Jim
*Interesting,Still seems about 2 inches too thick. Span doesn't seem that excessive either. Is this your residence or business or both? Why did you decide to go with a structural slab?Gabe
*At the risk of hijacking Brian's thread...Don't know entirely why the engineer went 8 instead of 6. But LOVE the solidness and always trusted his decisions. Do know if we took two inches off, I _never_ would have fit everything in (someone else might have, but it was pushing me). With a full inch of concrete beyond the rebar top and bottom, plus a 6 and 4 top and bottom, that left 3.5" max for everything else. Running more than half mile of hePEX between the rebar mats was tough enough on knuckles! :) Getting sufficient slope on plumbing was also work. Add in 2" electrical conduit for the main service, and it was getting tight.It's my residence. House is a Monolithic Dome (thin-shelled-concrete dome). 5,300 sq ft heated, 2,000 unheated. Bermed 18' along the back--cut into a mountain--so the slab also serves as a diaphragm, if I remember the discussions w/ the engineer correctly, spreading the forces equally through the dome. Also, better RFH than the gypcrete floor we have upstairs--good thermal mass.
*Thanks Jim,Got a better feel of the "why" part.Gabe
*JIM K:Radiant heat and bamboo "hardwood"? Though I have no experience with radiant heat, I would have to be suspect to the performance of some bamboo flooring products in this scenerio. I've seen some good and BAD in the bamboo manufacturing process.I've seen 2 ply and 3 ply and I have a 3ply in front of me that shows 3 voids on one end cut in the lamination/glueing process. I'd be careful with this one regardless of what the supplier says, and ask to some completed jobs that have been down for a year or so.That stuff is so soft too, and if anyone chooses a prefinished I've heard through a distributor that the finishing process is being done by hand in some cases. I see finish flaws often. I'd like to see an actual hardness test on this stuff as I've seen dings that parallel pine and other soft hardwoods.
*Ken, don't forget that the stuff from over the back pond uses formaldahyde as a base for it's glue. Lot's of offgassing.Gabe
*I guess at this point I'll just have to let you know. I did not get the prefinished, and I like what I've seen of the boxes I've opened thus far. Thinking about Waterlox, based on what I've read in Breaktime. Time will tell. I'm already committed, so...On a totally subjective note, our bamboo was grown in the JiangXi province of China, and by sheer coincidence, our daughter was born in JiangXi as well. Gotta believe there's good karma there! :)
*This thread seems to be wandering a bit so here's my 2 cents on bamboo. I spent a week in China this past May and when we visited the Imperial Palace quite a bit of renovation was going on at the entrances to many buildings. Temporary stairs were framed up using what appeared to be hemlock stringers and treads but all of the traffic surfaces of the treads were in turn covered with split bamboo. The bamboo showed almost no wear from thousands? millions? of people walking on the stairs. Looked like awful tough stuff to me. Also you guys wouldn't believe some of the bamboo scaffolding we saw on high rise buildings.
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Thanks in advance for any help you may have to offer.
I am getting ready to finish a house I am building. Construction is left in place forms (concrete) with radiant in floor heating on concrete floors (6" mesh reinforced, 4 to 5" thick) main and basement.
I want to install hardwood where appropriate. I have been told only a floating floor will do (i.e. Pergo, or hardwood veneer plywood).
Last week I visited a friend who had just moved in to a superbly built house with in floor heating (1" concrete on plywood) and hardwood floors. His builder told me the flooring subcontractor used quarter sawn 1/2" oak glued down with sub floor (i.e. polyurethane construction adhesive), and that this worked fine as bond as the concrete was good and dry.
I am tempted to try this but it would be an expensive mistake. If it works it would save me a lot of money, but more importantly give me a great deal of flexibility in terms of special wood borders, etc.
Any comments on this approach? Suggestions, experiences, etc., would be greatly appreciated.