Detecting leak in Warmboard with partially installed finished floors

Are you sure it's not leaking at the manifold? Depending on the connection type, a fiber washer will leak air until wet (or unless kept wet).

What brand if manifol. Some gave hydroscopic air vent that will bleed off air pressure

Did a church conversion using 3/4" wide white oak over Warmboard S a couple years ago. Arrived one day to find the boiler pressure at zero. We had installed the system and had it up and running for about two months to provide both building heat and to acclimate the oak flooring prior and during install. Figured it was most likely a staple someplace in a recent area. Having been burned before making assumptions (what if another trade had hit an odd line) -- refilled the system a couple of times and not finding any water anywhere started to isolate the manifolds (4) starting with only the oldest work area open. As I opened each manifold the pressure held for two days until the last manifold and sure enough the pressure was low the next day. We had about 4k sf of Warmboard and this last manifold had both crawlspace and finished ceiling under the floor ... was not happy. The flooring installer was fully instructed on the job (minimum board edge to Pex) and did a beautiful job. Still not seeing any water anyplace I started to layout the Warmboard Pex loops. It was not very hard ... had the layout from Warmboard and many pictures of the job showing the panels and any odd route that had to be made ... quickly discovered one board edge that was IMO too close to where my layout said a Pex run should be. Having this new knowledge I isolated out just that loop and the system ran w/o issue for a few days. It was only after I opened this last loop for the final time and over pressured the system -- that I noticed a drip and some wet insulation in the crawlspace. I had the flooring guy cut out the suspected line of boards and sure enough he called to say it was hit many time. The flooring guy then told me the lead allowed another person to work on the floor who had not been fully instructed and did not understand the full staple angle possible.

The solution was to take out and replace the Pex --- that became another issue. The contractor started to cut square holes and fix the Pex with the wrong splice. Regular plumbing and not Al Pex. I used a large whole saw and simply drilled holes for my patch locations. On the one end the Pex was missed as it got to the curve -- on the other end they got it too close to the curve for the proper patch connector and even hit the cross Pex. My solution was to remove the next board that thankfully was short and make the proper space for the AL Pex connector from Warmboard.

Couple of things to note. Since the panel is covered in one sheet of Aluminum -- the groves can hold a lot of water before any leaks out -- this will depend on the leak location on the panel obviously. This is why I never found any water until the very end. Also -- with the Al and the tight grove -- I'm not sure you will see any difference with any heat gun between anything leaking out and the actual Pex.

IMO -- You should layout the floor and see where the obvious close contact points are. Remember -- you can glue the flooring to Warmboard. Remove the tongue and glue in the fix. I have always used some glue -- even when doing an addition to a typical strip oak floor I used a few drops along a line to keep out any possible movement/ noise. Here we needed to fully gue as the boards are up to 14" .. Warmboard has an approved glue list

hot_rod said:

Different opinions on gluing down hardwood. Engineered woods typically okay. Solid wood needs to move a bit with humidity changes, that is why you have the T&G joint to accommodate movement. The wider the board the more potential movement.

Panelization is what can happen when the wood is stuck down with glue. It’s pretty ugly when it happens.

A good wood supplier will know how to fasten the various woods.www.launstein.com has done a lot of research on wood over radiant, they and the oak flooring association used to do seminars at RPA meetings.

Just a heads up.

Making sure the wood is properly dry and stays that way is paramount. The nice thing about Warmboard is that full panel Al layer. No moisture from a basement or slab is going to be traveling up to the underside of the finished floor boards and changing the humidity level of one side of the board. Warmboard also allows for the lowest water temp. Another major area is the subfloor ... I have seen panelization shown and it always seems to occurs as the subfloor moves and pulls the finished floor with it. When doing a retrofit system there is always a possibility of finished floor movement because the subfloor is going to move ... different systems are going to have hotter water ... more heat will dry out a floor. I have seen more movement over plywood vs random board subfloor system of old.

With wide boards you almost have to glue and the approved glues today have a bit of give to them vs the rock hard of old ... I still advise to keep glue out of the T&G. I personally have never had an issue with wide boards and Warmboard and I was a very early user of the product when it came out in the early 00's.

Warmboard may be an expensive product .... but it has a lot of advantages that can't be ignored. Warmboard has almost 30 year history and I have never seen any of the floor or wood associations using it as the subfloor when testing .... another issue is floor finish. Floors not acclimated can have finish cracks and cracks of the joint when the floor drys .... The finish is acting as a glue as it seeps into the joint.

As an added step -- I also give a quick once over to the underside of all the boards before they go down and after they have been in the rooms for a while. Time is important and that is often a rare commodity when doing new construction

Pexalpex couplings have dual o-rings to make a better seal. A more substancial crimp collar also. Looks like Mr Pex still offers these. It does require a specific crimp tool.

I hate to see you put water against that new hardwood, but hot water shows quickly with IR cameras. I'd wonder that hot air would also? Helium can be used with a gas sniffer. Often used to find micro leaks in vacumn systems.

I took a hardwood installer class at the old NOFMA, the national oak hardwood flooring manufacturers association, Micky Moore was the tech director and instructor. He taught that hardwood cleats were the prefered fastener, better hold and they allows some movement.

Another trick with 1-3-4" long cleats was to put a 3/4" block under the rear of the nailer. This drove the cleat at a shallower angle, so it could not reach the tube. Still plenty of hold with the serated cleats.