My radiant system we are installing has aluminum transfer plates between plywood sleepers over subfloor. We ordered them from a seller on ebay for 1/2" pex and just realized all the plates are actually 1/2" deep, and as you know the pex is actually 5/8" so the pex sticks up 1/8". I never noticed before, but as we put them in the floor there is a noticable lip now and hardwood can't be installed. Its too late to return them now and I wanted to see if anyone had any ideas of a solution? I was thinking maybe try to get them repressed? Or possibly putting some kind of 1/8 underlay between rows or pex? But then that might block some heat transfer. I really don't want to order and pay for new ones, but don't want the heat to suffer.

One of the many hazards of DIY design, but all is not lost. I would install the 3/8" (1/2" O.D.) PEX the plates were intended for. Another hazard for the radiant floor DIYer is thinking he has something he hasn't when all done.

How is it a hazard for the DIY when they sent me the wrong product? A 20 year "PRO" could have ordered and got the exact same thing, wasn't a mistake because I am doing it myself, was the suppliers fault. I aslo already have the 1/2" Pex. Any other suggestions?

Will your 1/2 pex even fit in??? if so 1/8 Masonite, ply or door skin strips to add height would work, your on the right path, its not a staple up, net loss of heat will be minimal. If pipe is in place no reason to go backwards. 3/8 will work as well but your runs can only be 200 feet. Sell your 1/2 pex on E bay. wash
Dan

The 1/2" pex fits in perfect on sides, just a little too tall. Think they just made it wrong. I was thinking 1/8 ply or what about that aluminum insulation like they use in attics? Wasn't sure cause that is a reflective material. Would it reflect the heat down instead of up or could it radiate it up and be even better? Thanks for the help. A couple runs are over 200' so 3/8 wouldn't work. Thanks again

Masonite is a good choice, consistent, flat, 1/4 cement board may be a good choice, some heat mass. don't think aluminum insulation would do much supporting future floor.
Dan

Seems to me that with wider spacing of the sleepers, the aluminum would just bend downward.

Fits like a tight shoe...it doesn't. I often make mistakes (even at my advanced age) but have learned to recognize and correct them quicker.

It is a hazard then for the DIYer in not recognizing the problem before installation. My suppliers send the wrong stuff every week. I send it back. The point is about exerience and support. I try to help, but it comes with a sharp edge, benefitting those who appreciate the candor and don't want to be taken in by a few online vendors who just sell stuff. In their defense, if you know what you're doing, you don't need their help.

3/8" can work over 200' if you have done the math. The aluminum "insulation" (bubble foil) is not a proper insulator or conductor. It is instead a sham. Aluminum can be conductive and reflective at once but will only reflect in free air to put it simply. If you compress or somehow contact the surface with another is a great conductor of heat AND electricity. With the bubble it is compromised as a conductor and is not used to any measurable effect in radiant heating applications, not even or especially under a slab or sandwiched between floor layers.

You could measure tube and emitter or just try a piece of 3/8" PEX. You may also shoot cement board on top of all, but the tube may not like it long term and noise is a distinct possibility. Wood sleepers will do, but save the sand for the sandbox...I know that would be next suggestion since an "established company" promotes this junk science.

Dan has a good idea, as he so often does and I would consider it.

My point has always been caveat emptor.

I didn't install it yet, I noticed before hand. I got a hold of the seller and apparently thats how they make them because they assume everyone is using them UNDER the subfloor where it doesn't need to be perfect. So they won't give me money back. I tried spacing a little bigger and it doesn't flex down enough. What if I use that 1/8 material they use under laminate and some hardwood installs? Would the heat be ok to transfer through that?

Bad move on the seller to not offer refund. Not ALL systems are staple up. We sell a lot of plates and my rough guess is 50% are RHT Floor panels, 50% staple ups.
Further how does it work as a heat plate on a staple up if the pipe is not captured.
Onward, you can build up with an 1/8 inch or 1/4 inch and be OK. You as I said are on the right path regardless with the pipes on the inside of your building envelope rather than pushing your heat through the floor with a staple up.
Good luck, don't worry
Dan

Gotta love Ebay.

this seems like a noise concern.

Question I have
Is the floor going to be a solid wood nail down? floating floor ect. If I had this problem I think I might use the 1/8 inch masonite as sleepers, cheap and hard . I would think it would take nails best. The cement board would shatter at the edges as you nail, then you got another problem to deal with.