Thoughts on a "radiant ready" project

dankrist

I live in an old (1895) home and as we've only been here a year, we're chipping away at the maintenance and update work the previous owner never got to. One of those projects is adding a new subfloor layer on the main level and then new finished flooring. It's currently an ugly mishmash of past updates with plenty of gaps that open right down to the unconditioned basement. Ideally, I want to lay radiant board and tubing, but we have more air sealing and insulation work to do before it makes sense, imo, to run it.

My primary question is whether it's fine to leave it unpressurized until we're ready to plumb it? It's not in a slab, obviously, and we would still check for leaks before laying the finished floors and cap the tubes. It would be much easier not to set up a manifold at this point and do that at the same time we have other plumbing work done.

If you have any other guidance or cautions that spring to mind with a project like this, please share!

Zman

It is a good idea to leave the new system under pressure during the renovation project. If a tube gets hurt, you will know who and when.

hot_rod

An air pressure test left on throughout construction and final flooring is an option. If you don't want to charge it with water.

Radiant23

We do a lot of radiant tubing above floor. I always stress to get it wet with water ASAP. It is a pain in the neck if it gets hit and leaks, but with water everyone knows in about 2 minutes if a tube is leaking. With air, no one pays attention. How much damage can water do to a house in the middle of a build or renovation? I get if it is above finished area, but aside from that, that’s the way to go.

EdTheHeaterMan

Radiant23 said:

We do a lot of radiant tubing above floor. I always stress to get it wet with water ASAP. It is a pain in the neck if it gets hit and leaks, but with water everyone knows in about 2 minutes if a tube is leaking. With air, no one pays attention. How much damage can water do to a house in the middle of a build or renovation? I get if it is above finished area, but aside from that, that’s the way to go.

You have a good point, but perhaps the best of both worlds would be a great compromise. Charge the system with 10 PSI of water connected to a plugged off manifold then add an expansion tank to take up any expansion and contraction over the course of construction... be it weeks, months or years. In my own home, I put tubing in the concrete slab and pressure tested it before the concrete pour. I didn’t even own a boiler yet. That tubing sat there for 3 years with 10 PSI air pressure capped off in the crawl space of the original part of the home. Then there was a slow spring season, and to keep the guys on the payroll, I finished the rest of the house with staple up, and installed the boiler.

The 3 year old tubing still had 9 PSI pressure after 3 years.