How to install pex tubing in concrete

Unless using a salt-resistant concrete sealer, do not salt the slab during the first winter — use sand instead. Avoid costly slab and PEX tubing repairs Confirm in advance that any chemical additives used in the concrete mix will not react with PEX tubing. Do not step on PEX tubing. While PEX is a tough pipe, it can be damaged by a piece of rock or other abrasive stuck in an outsole of a shoe.

Pressure-test the PEX system before, during and after the pour. This would help to identify and address any possible leaks in PEX piping at early stages. More details on pressure-testing can be found here. A b, crack-resistant poly piping is preferred and should cover sleeve over the PEX pipe at least Sleeve ends should be duct-taped to prevent concrete mixture from getting inside.

If using a split pipe cut open length-wise , tape the seam also. Remember that when repairing a PEX pipe with any fitting, it must be isolated with electricians tape to avoid a chemical reaction. If the system is pressurized during the pour, location of a leak can be clearly seen in most cases and can usually be remedied quickly.

Do not leave PEX exposed to sunlight for too long days at most. While different PEX manufacturers may have day exposure limit and in some cases even more UV-stabilized PEX , a safer alternative is to cover PEX with poly tarp or other non-abrasive covering until the slab is poured. Typical PEX installation process in a slab When slab base, vapor barrier, insulation, reinforcement if used and radiant heat manifold s are installed, PEX tubing installation can begin.

Start installing PEX. Determine the circuit loop to install first and select appropriate PEX coil length from your list of materials. You may connect PEX to or near the manifold, but always leave ft spare in case manifold location will shift and often it will. Secure the elbow to the reinforcement, or, if not available, directly below the manifold station. Gradually uncoil and secure the pipe using zip ties, wire mesh clips, foamboard staples or other approved means. Do not use metal rebar ties to secure PEX.

If using PEX rails, these must be installed prior to installation of tubing. Also consider that smaller rolls ft vs ft weigh less, are easier to handle and the price difference per ft is considerably small. Use steel PEX bend supports anywhere where tubing makes a degree turn. Never use PEX fittings of any kind brass or poly in a concrete slab unless it is necessary for a leak repair.

Following the layout, run the PEX pipe back to the manifold, completing the circuit. Proceed with the same manner for all other PEX circuits. Pressure-test the system. Unless you want to test each PEX line individually, connect the tubing to the manifold do not cute the pipe yet — leave ft length protruding from the slab.

Open all the circuits, close one of the main shut-off valves on the radiant manifold supply or return and connect the pressure testing kit pressure gauge with Schrader valve or compression hose adapter.

Since pressure testing in radiant heating is always below psi, a psi test gauge is adequate. A minute minimum test is required at pressures psi range. Duration requirements may change based on local codes. Pour the cement. An overhead pump truck is the best option, since it will minimize traffic over the installed PEX tubing and will reduce chances of damage. Be sure to keep the PEX system under pressure and monitor it when pouring concrete. The concrete can then be finished in a normal way.

Basic materials for radiant floor heat installation in a slab 1. Barrier PEX is much more common and is generally a preferred choice. This size is adequate for all small to medium size jobs both in residential and commercial projects.

Manifolds Manifold is the central distribution station for all of your PEX tubing circuits. The size of the manifold must correspond to the number of circuits in your radiant heating system. These are sold in pairs supply and return and include flow indicators, flow regulating valves and other basic components. Each copper header manifold is sold separately. Insulation Insulation is a must for all slab-on-grade systems. It prevents heat loss and allows for quicker warm-up of the slab.

In cases where pipe is positioned directly over the insulation, PEX staples are the only way to secure it. PEX Rails — a great accessory overall recommended for both thin non-structural and thick reinforced slabs. Since the concrete slab installation is fairly simple, many people fail to follow some simple yet very important steps thinking that it will work no matter what.

To make sure you do the work right, please read this manual. This layout is part of our free design assistance and many of our customers find it very helpful. You should try to use all of the tubing that was specified, space it out reasonably well, and make sure the tubing lengths are neither too short or too long. In areas with a lot of windows, the tubing can be spaced closer. In the middle of the room or in closets, space it further apart. These recommendations are general in nature.

As with any building project, be certain to check with your code official before starting the work. Be sure to also read our Design and Construction Manual and to give us a call with any questions. All Rights Reserved.