tar paper outgassing/radiant heat

Ray_6

Does any one know, if with age, tar paper outgassing is less of an issue with staple up radiant heat? Will be using Watts radiant tubing right up to the subfloor. Maximum water temperature is to be 140 degrees on a (-6 degree day). Wood above the staple up is 1/2" subfloor and 3/4"pine with the tar paper in between.
Interior walls of basement beneath are insulated but the space is unheated. Usually 55-65 degrees there. But woodstove was in use upstairs in that part of the space 12 x 24 for all 27 years. No other heat source except passive solar nearby - 4" of concrete heat sink on the other side of the floor 8x24 runs parralle to floor. Chimney was in center of home so there was also that radiating some heat.
The boards are 9 1/4" and have been painted 3-4 times in last 12 years. Did anyone find older floors like these outgassing? Also, is the wide board cupping an issue after 27 years? Thanks. Ray

Al Letellier

outgassing

The very first radiant job we did, we had this problem. It was a finished, enclosed porch in the home of a federal judge, and guess what, it stunk up the place!!! We offered several courses of remedial action, but the good gentleman waited it out and the odor stopped eventually, and never got a call back on it. Whew!!!! The system worked great and we've been called back for other work,so....
I am very careful about check this out and will never do it again without informing the homeowner. If they agree to proceed with the tar paper in place, they sign a disclaimer.

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Mad Dog

I used tar paper for about 8 years and never had a problem, but.

....didn't want one either...switched over to red rosin paper a few years ago, just to play it safe. This is on wet pour radiant jobs though, which kind of envelope and block the tar paper, under an existing wood floor, your kind of stuck - make them sign off on it. If the wide board floor ain't cured after 27 years you've got other moisture issues. I just keep the temp as low as I can go and heat the room. Mad Dog

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Mark Hunt

I have


walked away from jobs with tar paper under the sub-floor.

That odor will be there forever!



Mark H

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hot_rod

It happens

but usually over 140. At least in my experience. Make sure you meet the loads comfortably at 140. Above that you are asking for "smell"

Actually 140 is about the max temperature the wood people are comfortable with, concerning direct contact for extended periods, I've read. Same with sheetrock and gyp products. If in doubt go with the transfer plates to reduce necessary supply temperatures.

hot rod

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kk

how about subfloor adhesive outgassing?

We're laying 4 and 5 inch walnut planks down over radiant heat and the installer wants to use glue and nails. Is there a problem with the radiant heat affecting the glue or vice versa?

Alan(CaliforniaRadiant)Forbes

SF job

We may have a job coming up in SF where the owner knows there's tar paper between the hardwood and the subfloor and wants radiant heat anyway.

Design temperatures are a lot warmer here and it's a fairly tight house. If we get the job, we would use thick extruded aluminum plates (Thermofin) so that we can run low water temperatures and an outdoor reset system. This would reduce the amount of any outgassing.



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John@WattsRadiant

test a sample of the tar paper

If you can get a sample of the tar paper from the floor, put it in an oven at 120 Deg F and see how badly it smells.
John

hot_rod

reconsider

gluing down the hardwood. Wood really wants to move a bit with humidity changes, etc. Hense the tounge and groove joint, and angled nails through the tounge!

Trying to "lock it in" may result in panelezation (sp) This is where large areas of the floor move a a section producing very wide gaps in areas. I have seen this happen with site applied finishes also. The finish kinda glues the whole enchilada together causing the same issue. Sometimes.

As always the key to sucessful hardwood is conditioning the wood before application then keeping the moisture in a narrow range.

Laminate or engineered products are a different story. I have seen these glued down sucessfully. Much less movement in a laminated product. Happy flooring!

An electric fry pan is another way to "test" samples of asphalt impregnated felt paper. Use adult supervision :0

hot rod

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Mike T., Swampeast MO

I'd certainly heed Hotrod's advice

regarding gluing down natural wood. While walnut is known for being nicely dimensionally stable, it STILL moves.

I believe the ideal width/thickness ratio of blind-nailed T&G flooring is 3-1. I believe the finest floors using wider widths are chamfered slightly at the edges to help hide the inevitable cracks--and sometimes even pegged into the subflooring (not the fake pegs). This isn't the same as the chamfers on engineered, prefinished flooring--those are there to hide slight irregularities in height.