Radiant under an old top nailed floor

cliftronic

Several years ago we installed a radiant floor system underneath the first floor of our old house (it was built in 1924). By attaching it to the ceiling of the unfinished basement and insulating underneath, we were able to retrofit the system without too much work. It works great and we are happy with the heat.

However, our old flooring on the first floor is top nailed red oak which sits on 2" shiplap underneath. Since this surface is constantly getting heated and cooled we have had a consistent problem with the nails punching up above the floor. In fact, every two weeks my daughter and I get to play "whack a mole" with a hammer and nail punch in order to keep the floor somewhat smooth. We have also lost much of the putty crack filler between the boards. It looks bad and is getting worse.

The question: is there anyway to save this old wood floor or should we just nuke it from orbit and install an engineered wood solution?

Thanks!

SWEI

Can you tell us more about the system? Boiler, piping, controls, etc. will help us to understand what you have there. I'm guessing there might be a fixed temp boiler or perhaps a tankless water heater driving it?

Gordy

Expansion/ contraction because of two things. Wild humidity swings from season to season, and poorly controlled floor temps.

Top nailed is deffinetly not the best method for fastening flooring. Once the nail works loose, and is driven back in the same hole the cycle will continue until there is little holding power.

You must be running pretty high water temps to drive through that much floor detail. Did you use plates?

Some pics of the flooring, and some information on the present system set up may save your floor.

Jamie Hall

Whatever, you don't need to remove the floor. It's a bit of a nuisance, but there is a fix: get some GRK trim head screws from McFeelys (mcfeelys.com) (part # 082-FIN for 2 3/4", for example) , same length as the nails. Screws, not nails. And instead of playing whack-a-mole, when a nail comes up, pull it and drive a screw back in the same hole.

Gordy

That's an idea worth trying Jamie if you can get the right size screw dia. to nail used. I believe #9 trim screw is biggest dia. You can get. Be cautious with the under floor radiant. It will be easy to over drive the screw.

What will happen if you can get the screw to bite is the flooring will stil swell, and expand/contract working the flooring up on the screw head instead of the nail working up out of the board. Lifting the boards.

Firecontrol933

The first question would be: Does the floor heat cycle on and off to maintain temperature? If the answer is yes then the water temperature that is being supplied to it is too high.
The combination of too high of temperature and cycling will very easily cause issues with a new wood floor also.
The answer is to have the floor's water temperature controlled by a reset system. The reset control will vary the water temperature according to how cold it is outside. A finely tuned system will put only the energy to the floor that the room(s) above need to maintain temperature.
Where wood is concerned there is a maximum amount of btu's/sqft that should be applied to the floor system, if the space needs more than that amount then a supplemental heat source would be needed during those cold days requiring the excessive temperatures.

Zman

Firecontrol933 said:

The first question would be: Does the floor heat cycle on and off to maintain temperature? If the answer is yes then the water temperature that is being supplied to it is too high.
The combination of too high of temperature and cycling will very easily cause issues with a new wood floor also.
The answer is to have the floor's water temperature controlled by a reset system. The reset control will vary the water temperature according to how cold it is outside. A finely tuned system will put only the energy to the floor that the room(s) above need to maintain temperature.
Where wood is concerned there is a maximum amount of btu's/sqft that should be applied to the floor system, if the space needs more than that amount then a supplemental heat source would be needed during those cold days requiring the excessive temperatures.

This was a "one post wonder" from last December. Never answered questions never posted again.
Probably not worth your time....