How to Install Wet Underfloor Heating

Installing underfloor heating is a popular option amongst self builders. It will allow you total temperature control on a room-by-room basis and because it generates more radiant heat it also reduces drafts, moisture levels and airborne allergens.

When opting for a system, you will need to decide between water (wet) or electric (dry). Water-based systems are suitable for use with solid wood floor finishes, oak for example, because the water flow temperature is low (between 40-60 degrees). Ask your underfloor heating company to tell you floor and room temperatures so that you can check the suitability of your chosen floor finish. Due to the low flow temperatures, wet systems will also complement Renewable heat sources perfectly, such as ground or air source heat pumps.

Plumbing Tips

Reheat Solder When You Can’t Cut a Pipe

The best way to disconnect a soldered pipe is to cut it. But sometimes you can’t—either because you can’t get a cutting tool into the space or because cutting would leave the pipe too short to make a new connection. The solution is to heat the joint and pull off the fitting as the solder melts.

Have a wet rag handy and immediately wipe away the molten solder before it hardens. (Wear gloves to prevent burning your fingers!) Sometimes a quick wipe will leave the pipe ready for a new fitting. More likely, you’ll have to scour off some excess solder with sandpaper or emery cloth before you can slip on a new fitting.

DIY Tips

Want to add a personal touch to your home? Then get creative to add style that’s one of a kind to your home. Patchwork, knitting and crochet can all be used to add chic soft furnishings and accessories to your home, from cushions to throws and more. If you are new to crafting there’s lots of advice available online including helpful craft tutorials. Also take a make do and mend approach to upcycling existing pieces in your home with paint, decoupage or fabric.


Whilst wet systems are typically associated with new builds, to allow space for the piping and adequate insulation, they can also be retro-fitted with minimal increase in floor height. They are also inexpensive to install and run.


“If you elect to have off-peak (heures creuses) electricity, then EDF will provide you with wiring controlled by their equipment to switch your off-peak system on and off. The EDF off-peak equipment is usually a relay located beside their meter and fusegear. This relay is meant for the control circuit functions of your contactor (contacteur) or off-peak relay (jour/nuit) only. It must not be used to directly control equipment. The EDF relay is timed to operate in the usual manner at the predetermined off-peak times”

Excerpt From: Thomas Malcolm. “Electricity in your French house.” iBooks.


Here we show you how to install a single room heating pack from Robbens Systems in 10 straightforward steps. These packs come in sizes varying from 14 to 42 square metres. They include a pre-assembled manifold complete with a programmable thermostat, pump, isolation and water temperature control valves and are suitable for screed floors, typically providing an output of up to 100watts per square metre.

1. Clean the sub floor of all debris and add a damp proof membrane (DPM) if necessary. Any sharp irregularities should be removed either by filing, grouting or cutting away.

2. Lay the floor insulation as neatly as possible taking care not to leave large gaps that could fill up with screed. Tape the joints and lay polythene or DPM to stop the screed going under the insulation.

3. Fit the pipe fixing system to the insulation at 90 degrees to the direction that the pipe is going to lay.

4. Mount the manifold on a wall in a suitable location. Check that the surface is strong enough to support the manifold weight and any connecting pipe work. Always mount the manifold before laying pipe work, making sure you work from the manifold with each pipe loop and connect each pipe tail when it is laid.

5. Make sure the underfloor heating pipe is fitted to the flow side of the manifold (this is clearly arrowed) once the end of the pipe has been reamed with the tool provided. This ensures the sealing O-rings are not damaged as the pipe is located onto the joint.

6. The pipe needs to be laid out from the manifold to the furthest point of the room and returned back to the manifold in a ‘snake-like’ pattern with approximately 200mm spacing between each run of pipe. Larger rooms may have two or three loops of pipe in them and each loop should be laid in approximate equal lengths (not exceeding maximum length of circ. 80m). Fix the pipe down by walking it into the clips. The pipe will not be damaged by walking over it, due to its strength and multilayer construction.

Laying Underfloor Heating

7. Once the entire pipe has been installed the system should then be pressure tested with water. This will ensure that there are no leaks in the manifold, joints or pipes. The screed should be laid immediately after and pressure should be left on while this is being laid. A standard sand and cement screed should be laid in accordance with CP8204. It should be well mixed, well compacted, 75mm thick, and cured not dried.

8.The manifold flow and returns must be plumbed in after the boiler pump and before any other radiator or hot water zone valves, allowing the manifold a complete restricted flow and return from the boiler. This must be carried out by a competent plumber.

9. The Robbens Systems underfloor heating pack comes with a programmable room thermostat so that the area can be controlled independently from any other room or hot water system. Again the wiring for the thermostat and boiler connections should be carried out by a competent electrician.

10. The system should not be turned on until the screed has been allowed to cure as turning the heating on too early could damage the screed. The manifolds have an in-built water temperature control and should be run first at a lower setting to allow the screed and floor finishes to warm up slowly before increasing to its final running temperatures. Start up and final temperatures will be specified by the underfloor heating company.

For more details …

Related Post

Quick tip

Paint effects

Try out different paint effects to give your home a new look, try rag rolling, stippling or marbling. If you’re handy with a paint brush and eager to let your inner artist out, then consider painting a trompe l’oeil effect on a wall. Remember you could simply project an image onto a wall and paint around it – you don’t need to be a great artist to have a go at this. So get your paint brushes out and get creative.


Quick Tips

How to flush a water tank

Have you flushed your water heater lately? This boring but important chore should be done at least once a year to remove sediment that accumulates on the bottom of the tank. That’s especially true if you live in a hard-water area. The task is easy to blow off because it’s out of sight—but skipping it is costing you a lot. Sediment buildup reduces the heating efficiency of your water heater.


Give is your thoughts by email ….

or join our Forum and discuss your tips or experiences Visit the forum

Electrical Tip

“Although at first glance lighting, sockets and off-peak heating in France may all appear familiar, closer investigation will reveal that the installation methods are different to those employed in the UK”

Excerpt From: Thomas Malcolm. “Electricity in your French house.” iBooks.


We are a new website, we are still growing our content, we want everyone that is renovating in France to help us feature what we all wanted to know when we all started, contact us with all your experience and tips, we live just south of Celles Sur Belle, in Deux Servre, 79, and are just about to start out on our next renovation, every job we start on, every problem, product or skill we need to learn about i will try and find some useful information on the internet and share it with you, yes I could do this by sharing it on facebook, but the problem is it just helps facebook and disappears down the timeline, here links and articles will be searchable and here permanently for you to book mark and refer to, so watch this space … and if you have links and articles that have helped you let us know !!1

Leave a comment

Your email address will not be published. Required fields are marked *

%d bloggers like this: