maderuyck

I am researching a boiler/water heater combo that heats water for shower sink etc and also heats and pumps water through a radiant floor heating system. I would like to avoid baseboard units in the basement (exisiting slab-unfinished basement by the way). So here's the question: has anyone heard on laying down treated sleepers on the slab, running the pex tubing in the bays and installing plywood over that? Is there a way to heat the basement with this radiant system of tubing and fins without the exposed fixtures?

thom

There are systems for installing radiant below a plywood deck. In this case, the slab will be an issue. Unless you properly insulate the system from the slab, you will spend a lot heating the earth.

FemaleAstarCO

I am not sure how efficient it is but I have seen a flashing installed in this circumstance it reflects the heat. Good luck

able14

You should insulate the slab with either foil bubble wrap or high r foam stadler makes a plastic mat you snap the tubing in and then you can pour another thin slab 1/12 inch and intall tile or lineolum you can use sleepers with heat transfer plates but will have to run water temp hotter and system wont heat up as fast make sure you do a heat load if you have alot of glass or real poor insulation you might not get enough heat from the floor

sawyerEd

Be very carefull about trying to retrofit in/on slab heating unless it has been designed and insulated to prevent the heat from escaping out from beneath the building. Usually floor convective systems have to be built in before the slab is poured. Loop length and piping distribution is important as well as manifold design. Infloor water pipes, 85 - 95 degrees, are not warm enough for DHW, 125 - 140, so this has to be a separate system. Also heat transfer, conduction, out of the pipes to air is substantially slower than into concrete slab and there is no heat storage by the mass of the slab so will have hot spots and fluctuating temperatures. get some engineering advice before proceeding.