Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.
Contractor wants to pour a slab.........
Alan (California Radiant) Forbes
Member Posts: 4,214
........but doesn't know yet if the finished floor will be: 1) bare concrete, or 2) hardwood.
How do you install the tubing, i.e. spacing. And then if they want to go with hardwood, how do you construct the floor? Two layers of 3/4" plywood with hardwood on top?
How do you install the tubing, i.e. spacing. And then if they want to go with hardwood, how do you construct the floor? Two layers of 3/4" plywood with hardwood on top?
8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hour
Two btu per sq ft for degree difference for a slab
Two btu per sq ft for degree difference for a slab
0
Comments
-
In only did one slab with two layers of plywood, it was a PITA. The plywood needed to be glued and screwed, and it really put the brakes on the heat transfer. I also tried sleepers in pours with not much success. I think the floating engineered, or glue the engineered wood directly to the slab is the best way.Bob "hot rod" Rohr
trainer for Caleffi NA
Living the hydronic dream1 -
-
I wouldn't do anything until you know what the floor coverings will be. Don't do it.0
-
Or just assume worst case scenario, carpet and pad.... and size accordingly.0
-
The scenario is quite a difference between bare concrete, and a solid hardwood floor assembly over concrete. The later could end up all most an r 3 depending on the assembly.
There is extra cost to the owner in planning for worst case with extra tube density, and higher awt that may not be needed. But if no answer can be arrived at then no other alternative but to plan for worst case.2 -
Floating engineered floor, R3? I'd think closer to 0.5... For 3/8 to 1/2" thick.0
-
So you spend a little more on tubing and manifolds.... In the scheme of things I'd say a minor cost. Being embedded in concrete I'd rather be dead-on or slightly conservative if someone decides to change their mind and then realizes the required water temps are thru the roof to heat the space.0
-
Read original post.bmwpowere36m3 said:Floating engineered floor, R3? I'd think closer to 0.5... For 3/8 to 1/2" thick.
If the installer does double layer plywood, and then 3/4" hardwood. Recommended hardwood install method for hardwood flooring. That's an r 2.5. If the use 1/2" 2 layers with shorter nails that gets it down to just under r 20 -
bmwpowere36m3 said:
So you spend a little more on tubing and manifolds.... In the scheme of things I'd say a minor cost. Being embedded in concrete I'd rather be dead-on or slightly conservative if someone decides to change their mind and then realizes the required water temps are thru the roof to heat the space.
Walk carefully down the over design path. An extra grand is enough to throw some into an entirely different choice that leaves the installer with out the job.
For what it's worth over concrete coverings can vary widely in the unforeseen future. What worked for bare concrete may have lack luster performance for future owners that think they need carpet over a neutral concrete surface.0 -
I hear ya Gordy... but I also can't imagine bare concrete inside a home, even polished. Maybe a work space or garage, but living... to reach his own I guess.0
-
Double plywood over concrete, hmm. I guess you learn something new everyday. If it were me, I wouldn't be pouring concrete as the subfloor then.... barring a basement or on-grade construction.
So no option to have a floating hardwood on concrete without some plywood underneath?0 -
-
bmwpowere36m3 said:
Double plywood over concrete, hmm. I guess you learn something new everyday. If it were me, I wouldn't be pouring concrete as the subfloor then.... barring a basement or on-grade construction.
So no option to have a floating hardwood on concrete without some plywood underneath?
There are always options. Typically that would be a gymnasium floor assembly.
0 -
If there is going to be two layers of plywood plus flooring, the insulation r value should be higher then normal to direct heat flow. The wood will hinder the heat transfer.
Size for worst case and lower water temperature as needed. Make sure to install floor sensor to protect the finished floor should it turn out to be wood.:NYplumber:0 -
I told the contractor that he needs to know if he is using hardwood. If so, we would probably use a product like Warmboard-R which (I believe) can be screwed directly into the (well-drained) slab.
Yes, I agree that a concrete slab is not a very inviting finished floor, but that's often done these days. They could easily upgrade to tile as well.8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hour
Two btu per sq ft for degree difference for a slab0 -
Enter the project into the Uponor ADS software and you'll have your answers. You'll also be able to do "what if?" Having done hundreds of slab on grade projects, I'd rather have more tubing on 6 or 9" centers which lowers the required loop water temperatures, than struggling if the floor coverings change. I'd also be using pre-engineered hardwoods rather than the Bollinger method (2sheets of ply), Sometimes the owner "must"have regular hardwood. That can become a problem.1
-
-
Just the contractor I would want to hire........good thing your not king.0
-
I have wise **** moments time to time.known to beat dead horses0
Categories
- All Categories
- 86.3K THE MAIN WALL
- 3.1K A-C, Heat Pumps & Refrigeration
- 53 Biomass
- 422 Carbon Monoxide Awareness
- 90 Chimneys & Flues
- 2K Domestic Hot Water
- 5.4K Gas Heating
- 100 Geothermal
- 156 Indoor-Air Quality
- 3.4K Oil Heating
- 63 Pipe Deterioration
- 916 Plumbing
- 6K Radiant Heating
- 381 Solar
- 14.9K Strictly Steam
- 3.3K Thermostats and Controls
- 54 Water Quality
- 41 Industry Classes
- 47 Job Opportunities
- 17 Recall Announcements