Underfloor heating blog
With many people now looking for things to do at home during the COVID-19 lockdown, Chris Ingram, the Founder of Continal Underfloor® and ex-Chairman of the national trade association, explains how easy underfloor heating is to fit. Here, Chris takes you through how a competent DIYer can fit their own underfloor heating system, with support from a company such as Continal Underfloor.
At the start of the lockdown my partner gave me a To Do list of jobs around the house, including many that I had managed to ignore for several years. Now, after 9 days at home, I’ve done all the “fun” jobs such as “sort screws” and “paint WC”, and am left with “Loft tidy” and “Veg patch”. So, I thought a short blog on how easy it is to fit underfloor heating for a DIYer would be a good excuse to hide away.
Most people think that fitting underfloor heating is a highly skilled and specialist job, but that isn’t necessarily the case. You can fit it yourself if you are a competent DIYer, are quite happy to take on large jobs over several days, and have the support of a reputable company to call for help and tips (ahem – blatant plug: Continal Underfloor first started supplying to self builders and DIYers 20 years ago).
When someone asks me "can I install underfloor heating myself", my reply is:
“If you can lay a laminate floor and change a tap washer then you can probably manage it.”
But first, the type of system you need depends upon the type of project.
Single Room – these are obviously the simplest to do and take the least time. People often fit underfloor heating to just their kitchens or bathrooms. There are pitfalls however, with the main one being that kitchens and bathrooms have a small available floor area compared to the room volume (due to baths, shower trays, kitchen cabinets etc). This is why you MUST use a company that does the calcs for you and provides a CAD plan for you to follow.
In most cases you’ll be able to link into the existing radiator or towel rail feed, but you will need a controller such as our Small Area Pack. This ensures you get circulation all the way through, that you don’t unbalance your existing heating system, and that you have proper room temperature control.
A whole floor – many people still think you can’t have underfloor heating under carpets (you can), that you need to dig the floor up (rarely true), or that it can’t be mixed with radiators (it can). Doing a whole floor, rather than one room, is often the best bet because you can then ensure your floor levels are the same throughout.
The other benefit, although it is a much bigger job, is that you then have the greater energy-saving that underfloor heating provides. Individual room control comes as standard too, so you can keep the whole family happy.
Let’s now look briefly at the different types of fitting systems. Our Technical Sales Advisers will help you get the right system and explain the pros and cons in more detail when you call them on 033 800 1750.
Screed systems – unless you are new-building, breaking up an existing floor, or happy to raise your floor level by at least 100mm, then don’t go the pipe-in-screed route. Some will tell you that a liquid screed with a thin 12mm pipe is a good option (and we sell such systems) but trust me, they aren’t. These sort of systems are best left to a full new build. An option to consider however, if you want a screed type floor, is our ThermoDEK™ product – an 18mm thick interlocking underfloor heating screed board that holds the pipe.
Systems for wood / laminate floor finishes – most panel systems are suitable, but some have less rigidity so need an extra layer of chipboard or ply laid on top, which can reduce heat output. Generally though, provided the “kPa” (impact strength) is greater than 300, you can usually lay direct on top if the floor finish is at least 18mm thick: my team at Continal can advise on this. Panel products vary from systems such as our UltraSlim™ (waterproof, foiled, and only 15mm thin) to SlimFix® (foiled composite system that comes in 18mm and 25mm thicknesses).
Systems for carpet floors – most panel systems are suitable but will need an additional layer of plywood (6mm) laid on top. Ply, underlay and carpet are all insulators, therefore there needs to be a careful design in place. Please don’t risk buying components cheaply from an online store.
Systems for tile floors – most panels can’t take a tile directly as they are not strong enough, so you have to add a layer of ply. Or, they sometimes have a foiled finish that needs de-greasing and coating with special primers or adhesives. That’s why we developed TileFix®. It’s 500kPa (industrial grade) and is available in 18mm and 25mm thicknesses. You just glue it down with the supplied adhesive, pipe it, and stick your tiles down with normal flexible tile adhesive.
Systems for joist floors – this is where it gets very messy, time consuming and disruptive; however, for completeness I’ll mention them. You can either fit a panel system on top of the chipboard on the joists (allow 18mm to 25mm height increase minimum), go for a battened floor with dry-mix (eugh, but very efficient) or strip the chipboard and use our unique structural OneBoard® system. OneBoard® replaces the existing chipboard (usually 18mm), is fully tested by TRADA (the Timber Research and Development Association), and is only 22mm thick (a 4mm increase).
Room Controls – I could write a whole book on these. In brief, you have one thermostat per room, so your bedroom can be at 18°C while your lounge is at 21°C, and the thermostats can be as simple as a rotary dial or a full-blown, intelligent app-controlled system. An RF (radio frequency) system may be needed if you can’t run electrical cabling to the correct place in each room, but these are tried and tested now and work well. They will need to connect to a wiring centre to ensure correct safety “interlock” of your boiler or heat source (e.g. heat pump). Generally it is the electrical side that DIYers struggle with, so we recommend you use a competent person to fit and wire these. We supply full wiring plans, and we’re available on the phone to provide assistance.
Heat source – your existing boiler or heat source will usually be fine if the rooms currently have radiators. If it’s a new extension, then adding extra radiators or underfloor heating may mean you need a bigger boiler.
Floor heights – floor heights will change, so you’ll need to factor in tasks such as removing skirting boards, replacing or shortening doors, and making door wells for external doors (if you can’t trim them down).
Insulation in the floor – while panel systems provide a small amount of insulation, it really is minimal. You can never add too much insulation to your ceilings, walls and floors, so consider this when doing your planning. If it’s an older house with a solid floor, it may not have any insulation in the floor build-up, so you must add enough to comply with Building Regs. Our Technical Sales Advisers will chat through this with you and will let you know if they think you have a problem.
Pricing a UFH job – Step one: sketch your floor layout with dimensions. Step two: send them to a UFH specialist such as Continal. The company should discuss options with you and want to understand your project: if they don’t then run a mile. Once you have the cost for the system, ask if they support DIYers (most won’t but we do), then price up the rest of the works.
Installing your own underfloor heating sounds complicated I know; but with the right advice it isn’t, and this is where experience counts. If nothing else, just the planning should enable you to put off the dreaded “To Do” list. 😊