Introduction: ThermaSkirt- an Installers Guide by an Installer

An Intro

I've been installing ThermaSkirt for a few years now, and have always been proud of the fact that it's a little known gem. There aren't many plumbers out there that install it, whether because they are afraid of something new, or because they just don't trust the fact that it works. As a result I've traveled the length and breadth of the country (and beyond) installing this type of skirting heating in all kinds of properties.

Ultimately it's not rocket science, it can be a bit fiddly in parts, but certainly not rocket science. The skills required are all pretty basic, so long as they are used in the right way, in the right order, with the right level of care. Don't cut corners, don't bodge it up, and if you're unsure call the office- unless of course it's the weekend; DiscreteHeat (the manufacturer) close over Saturday and Sunday so you'll have to email.

The installation that I am using in this example, is for a customer of mine in Cheshire. As soon as I went to weigh the job up I knew that it's about as difficult as is gets when you come to ThermaSkirt. The customer wanted the DecoBM3 profile, which is the taller three pipe version of the standard ThermaSkirt; this involves splitting the feed into two in order to connect onto the existing central heating. Couple this with two deco threshold kits, and a standard threshold kit, its a pretty complicated run! What's a 'deco threshold kit'? If you don't already know that will become clear.

To install ThermaSkirt you'll need the following:

Tools (Required):

Chop Saw (you could use a hack saw if you're feeling brave, or you've only got a few cuts to make, but you've got to be accurate) - this of course is for cutting the skirting
Drill- Fixing the mounting brackets to the wall. I include relevant drill bits in this.
Nylon Mallet- bashing stuff, more specifically knocking the clips into the skirting- a standard hammer will do
Pencil/Marker- marking or pencilling things
Tape Measure- measuring walls and marking the skirting
Stanley Knife- (or 'box cutter' for my transatlantic cousins) opening the boxes, cutting foil, cutting packets open
Pipe cutters- cutting plastic or copper pipe for making the connections
Super glue- gluing the top strip together in the corners (regularly missed by other less trained chimps)
Snips- cutting the top strip accurately
De-burring tool- chamfering the cut ends of the skirting (this is provided in the spares kit included with order)

Tools (Optional):

Small hack saw/ Pad saw- cutting or revealing plasterboard
Tectite Demounting tool- used to uncouple the Tectite connectors included in the ThermaSkirt kits
Screw driver- will assist in getting the right fixing torque on the mounting brackets
Tweezers- helps to pick out top strip if you push to far into skirting gap
Crowbar/Lever bar- jacks up the skirting when fitting the bottom cover clips
Vacuum Cleaner- keeping your work area tidy if you're sensible, also shows that you care


Silicone Grease- (included) used to lubricate the ThermaSkirt fittings
WD-40 (cutting oil)- used to assist the deburring process and maintain blade life
Wipes- keeps everything clean, helps when pushing the top gasket into skirting

That's pretty much it, nothing extra special other than the demounting tool and the deburring tool, and one of those is included in the kit anyway! Let's crack on.

Step 1: Pre Install Prep

When the ThermaSkirt arrives, you'll have several long boxes that contain the ThermaSkirt lengths themselves, and one or two smaller boxes containing all the fittings and covers.
Personally I like to cut open the end of the long lengths and check that everything is there, and that the profile and colour is right. I've only ever had one order that was 'wrong' and it turned out that the customer dream't himself ordering a different colour. All was well in the end however, as we sent the skirting back, received the new skirting in the preferred finish a few days later, and I returned to fit it the week after.
After checking the skirting, I unpack the box of components, and separate the kits from their respective covers. That way I can lay them all out as pictured and use them as I go (throwing away the millions of tiny plastic packets you are left with). This saves me rummaging through the boxes and helps me keep track of everything that I am using.

You'll see in the picture that the packaging is unlabeled, this may cause some issues for a novice installer as I can imagine you would have no idea what you are looking at. However, since this installation took place, DiscreteHeat have started labelling packets.

Next, get a sample of each profile you will be using, hold onto this sample, it's going to be your friend throughout the process, and effectively acts as your jig for a large amount of the installation. If you haven't got one, cut a small piece off the end of one of your lengths. Deburr both ends of each sample as this will also help you in setting up your connections, and measuring your skirting lengths from the correct positions.

Step 2: Setting Up Connections

You can see from the drawing provided the designed layout for the ThermaSkirt. It connects to the existing central heating system at a set of 'flow and return' pipes situated under the kitchen units. These were put in by the builders who constructed the extension and were simply blanked off with two isolation valves for me to connect onto. I will just be using the Tectite flexi hoses to make the connections, which are a little more expensive but save headache and look good.

The fittings provided with the Deco BM3 system allow you to split the flow pipe at the point of entry, in order for the water to flow through all three pipes. From the feed position, the ThermaSkirt runs through two internal corners, then the 1st deco threshold kit, along a short run of skirting, into a standard threshold kit, into another short run of skirting into the 2nd deco threshold kit.

So 'what's a threshold kit? and what ON EARTH is a Deco theshold kit?!'
When the skirting heating runs up to a door way, you can connect to the skirting on the other side by simply fitting two pipes under the floor. In this case the standard threshold kit I installed prior to the builder re-screeding the floor (as pictured), across the single door out into the garden. So, the Deco threshold kit. My customer, as well as having a single door, also has a 4m long set of bi folding doors, and a 1.5m long floor to ceiling window. The deco threshold kit allows you to connect across these long spaces but also provides a built in heater effectively to create a curtain of heat in front of the cold glass, as well as carrying the water across to the remaining skirting on the other side. Installing these is where experience really comes into play.

I like to get all these various connections set up prior to measuring, cutting or fitting any of the skirting. Most rooms you can crack straight on with. If you haven't got any threshold kits on your job, you can skip the next two steps.

Step 3: The Deco Threshold Kit- Made Simple (as Possible)

There are a few simple steps to take when installing the Deco threshold kit. On the face of it, it can look a pretty daunting task. However, if you follow these steps it should be pretty straight forward.

  1. Mark the diagonal line between vertical ThermaSkirt and horizontal threshold heater.
  2. Cut through plasterboard and steel corner beading. I prefer to use a hacksaw as you can take is slow; a reciprocating saw is a little too violent and can actually crack the plaster further up the beading, so try to avoid this method.
  3. Remove plaster corner
  4. Mark around the tectite fittings to guide your cut lines
  5. Reveal or remove plaster board in the areas in which the tectites sit. This will allow them to sit back into the plasterboard slightly, making the covers fit better. This is an important step to follow, as its not immediately obvious that you haven't completed it until the end of the installation when you come to fit the covers. Without the plasterboard being revealed, the tectite fittings with foul the cover.
  6. Measure distance between fittings, cut and fit connecting pipe

Follow these steps again for the other side of the doors. Having the skirting connections set up as a jig allows you to mark the wall for a measuring point. This means that when you measure up the walls for your skirting cuts, you can be as accurate as possible, saving you any potential recuts or embarrassing phone calls to the factory.

Step 4: The Standard Threshold Kit- Made Simple (as Possible)

The standard threshold kit is far more commonly used in ThermaSkirt jobs, and is used to bypass internal doors, in order to connect the skirting on either side. Installing the threshold kit can take two forms, a solid floor installation or a suspended floor installation. I have included both; and one is far simpler than another.

Fitting the pipes

1. Solid Floor Installation

If, like on this job, the ThermaSkirt is being installed as part of a much larger renovation/extension project, and- like this job- doors are being removed, and floors being re-screeded etc, then fitting the pipes is a pretty straight forward task. I simply fitted and clipped the pipes in position as you can see in picture 1 and picture 3. Please note that before I left the pipes to be screeded, I notched out a piece of insulation and covered over the pipes. This means that once the screed is put in and levelled it will not make contact with the pipes and allow them to expand with the heat. I then left it to the builders to fill in the screed, and I returned once the flooring had been finished.

2. Suspended Floor Installation

Pictures 4, 5 & 6 are from another recent installation where I had to retrofit the ThermaSkirt to a room that was only undergoing a simple redecoration. As you can see from the pictures, I folded back the carpet, cut out the floor board directly in front of the door, and fitted the pipe work from one side of the door to the other. Also note, that I have cut out two windows from the plasterboard in anticipation of the fittings to connect the 15mm pipe into the ThermaSkirt when I come to fit it at a later date.

Step 5: Measuring, Cutting & Deburring

Now comes the high pressure part of the job. Cutting into £150's worth of aluminium.

Whilst it may not sound an awful lot of money, it is when its the customers. You've got to get the cutting right, and its time well spent measuring and working out twice over. Page 3 of the instructions provided in the ThermaSkirt kit is where you'll find the relevant cutting allowances.

I like the make a full cutting list of all my lengths, work out which pieces I am going to cut out of each supplied length, cut them, and then deburr them all at once.

You can see from the picture the I have placed the chop saw on the cardboard packaging that the ThermaSkirt is delivered in. This prevents aluminum fillings being scattered all over the place, and makes the tidy up far easier.

Before cutting, make sure that you are working in a safe area, and wear the appropriate protection such as safety glasses and ear defenders. Mark the skirting to the length you require, and cut each piece slowly and carefully being sure to cut the entire way through each piece.

Once you have cut the lengths, it is time to deburr the pipes. One of the pictures above shows we running the deburring tool down the front edge of the skirting. This removes any burr from the front edge ensuring that the covers will fit flush to the skirting during the final stages of the installation. When deburring the pipes, use WD-40 or similar lubricant to prolong the life of your deburring blade and help the blade slide around the pipe. As you can see from the picture, I consider a deburr on the skirting to be more of a chamfer. Opening the edge of the pipe out to a bell mouth, allowing the push fit fittings to slide into the ThermaSkirt easily.

Blow through each of the pipes to remove any large pieces of swarf, and if you are feeling really thorough, you can even stuff a piece of tissue paper into one of the pipes and push it through with your tape measure, this will remove any aluminium specks produced by the chop saw.

Once all the lengths are cut, deburred and ready to go, it's time to physically install the ThermaSkirt.

Step 6: Physically Fitting the ThermaSkirt- Wall Brackets

Summary of Steps:

  1. Use sample to mark bracket positions
  2. Drill holes for wall plugs
  3. Insert wall plugs through backing foil
  4. Screw wall mounting brackets into position

For the first part of this step, you will need your beloved sample. The sample provides you with the perfect representation of where your actual ThermaSkirt lengths will sit in relation to the floor. I tend to put a bracket into either side of the sample; on the Deco BM3 you'll need two brackets per side.

As you can see from the second picture, the ThermaSkirt wall mounting brackets actually have the centre point moulded into them. A 'v' cut into one side so you can run your pencil or pen down the side of the bracket, and your line will dip into the centre point, alternatively the bracket also has a semi circle cut out from the other side for a 7mm drill bit. On the contrary, I actually prefer to use a large marker pen to mark a dot in the 7mm semi circle, as can be seen from the pictures.

These marks are of course the position in which you should fit your brackets. I usually mark out, all brackets, and then drill out all holes. Clean up all the dust, before proceeding to push the wall plugs into the wall through the backing foil as shown in picture 6. This helps hold the foil in position when you come to screwing the brackets to the wall.

Once all wall plugs are in position, screw each bracket in place in turn ensuring that the bracket is tight to the wall, but still capable of rotating to a horizontal position. This will allow the skirting to move freely during heat up and cool down. Whilst it is only a few millimetres the ThermaSkirt needs the movement nonetheless.

Step 7: Physically Fitting the ThermaSkirt- the ThermaSkirt

Once I am happy that all the brackets are on the wall, all of the various pipe connections are ready, and that the skirting is cut and deburred; I like the fit all the ThermaSkirt at once.

Its very temping to fit a couple of lengths once its cut and the wall is ready, and do the others later, as it doesn't feel like you're making any decent progress until its actually on the wall. However, trust me, doing all the prep first is well worth it. Once it's all ready, the ThermaSkirt panels themselves go in very quickly. Simply clicking together and pushing back onto the brackets.

I always start at the feed point and work my way around the room from there.

Firstly decide which length of skirting goes where. This will then allow you to fit the correct fittings into the correct lengths. Use the instructions provided to decide which way around the stainless steel clips go. As a general rule, the 'winged' side of the clip go to the back of the ThermaSkirt on internal corners and TRV units. For all other connections the 'wings' go to the front as shown in picture 1.

Line the clip up in between the two pipes and gently tap into position with a hammer (or nylon mallet if you want to be cautious). Knock the clip all the way in, until the black plastic part is snug between the wings of the clip and the skirting. These clips ensure that the skirting will stay water tight under pressure.

As well as fitting the clips into the skirting, you will also want to fit the connectors prior to actually pushing the skirting onto the wall. Picture 2 shows me applying grease to the fittings before pushing them into the skirting. Not only does the grease make pushing the fittings in easier- it also protects the o-rings and allows for some expansion movement during heat up and cool down.

Line the first length of ThermaSkirt up with the fittings, then push the fittings into the respective pipes and keep pushing until the holes in the stainless steel clips locate with the lugs on the ThermaSkirt fittings. Theses are now sealed.

Once the ThermaSkirt fittings are push all the way into the skirting and the clips have located with lugs, push the skirting back onto the brackets. Sometimes when you push the skirting back you will find that the wall brackets aren't lined up with the corresponding teeth on the back of the ThermaSkirt. If this is the case, simply reach behind the skirting and either lift up or lower the bracket in order to get it lined up correctly. Once the brackets are lined up, push the skirting onto the brackets as far back to the wall as possible, as shown in picture 4.

Repeat this process for each piece in turn until all lengths are fitted and in place. Once all pieces are fitted. Its time to full up and pressure test the system.

Step 8: Commissioning- Purging Air and Balancing

Purging the Air

I always like to fill up and pressurize the system before finishing off the installation. This way I can ensure that it is all water tight, and working; reducing the need to undo any work should something need to be altered or replaced. In all my time installing ThermaSkirt there have been very few leaks, and those that did where usually a slight weep due to a pipe connection not being completely pushed into place. Simply resolved.

When I actually fill the ThermaSkirt up with water, I only open one of the inlets. If the ThermaSkirt is being fitted with the TRV valve unit, then close the lockshield valve. As seen in Picture1, the TRV valve is the top connection and the lockshield valve is the bottom connection. By isolating the lockshield and filling the ThermaSkirt up through the top TRV valve, you contain all the air within that run of ThermaSkirt.
Now that the air is contained in the skirting, use the bleed screw at the top of the return manifold as shown in Picture2. This will remove the majority of the air but probably not all of it. Repeat this process for each individual run of ThermaSkirt until all are done.

At this point you need to purge the ThermaSkirt of all remaining air. I like to do this by turning all other radiators in the house off except from one, normally the highest in the house (usually a towel radiator in the upstairs bathroom), which I leave 'on' but turned down to a low setting. I then fully open the run of ThermaSkirt that I wish to purge.

Because the skirting is made up of horizontal pipes, it cannot collect a head of air like a radiator. Therefore all remaining air is pushed along the length of the ThermaSkirt, and then will either be purged via the vent on the boiler or will collect in the other radiator that you have left on. Repeat this process until all lengths of ThermaSkirt get hot all the way to the end. Once they are hot across their entire length, you know that the air has been purged. Once the ThermaSkirt has been purged, bleed any remaining air out through the radiator.

Balancing the System

This process is key to ensuring that all radiators, including all runs of ThermaSkirt get hot evenly.

As a general rule the longest run of ThermaSkirt will create the largest amount of resistance in the central heating system. Therefore its advised to leave the lockshield valve of this run fully open.

From there work your way back through the ThermaSkirt systems in descending order of length. Ensuring that each one is getting hot all the way to the end.
Once all the ThermaSkirt systems are running and hot to the end, start opening up the remaining radiators in the property. Begin by turning the lockshield on each radiator by half a turn. After a few minutes feel each radiator to see how hot they are getting. If they are warm, make another half turn on each lockshield valve until the radiators are hot. If there is one radiator that's warm, and the others are hot, try turning the hot ones down slightly.
There's a little bit of trial and error here, but by working backwards it should be pretty straight forward to ensure that both ThermaSkirt and radiators are working to the full potential.

Step 9: The Beauty Treatment- Top Gasket

The Top Gasket

You'll find in your box of parts provided with the system, some rolls of rubber gasket. These are to seal the skirting to the wall and counteract any undulations in the plaster work. Discrete Heat do make different depths of gasket for the ThermaSkirt which can be purchased if your walls are really really bad and you have some big gaps that need to be filled.

I use a wet wipe or damp cloth to assist in fitting the top strip. The water creates a little bit of lubrication that eases the top strip into the channel.

Push the gasket into one end of the ThermaSkirt, wrap the wipe or cloth around your favoured finger and rub the gasket into the top channel along the length of the ThermaSkirt. I tend to cut each piece of top gasket long and fit it into every length before proceeding with the next steps. These steps are shown in Picture 1-4.

Once all the lengths of top gasket have been fitted, you need to mitre and glue them together in the corners. This is shown in Pictures 5-9. The glue I am using is a Loctite 'Brush on' Super glue, as the brush gives me very good control over the application of the glue. You can use any super glue really, as the top gasket is purely decorative.

Once the gasket is fitted, its time to fit the covers.

Step 10: The Beauty Treatment- Covers


ThermaSkirt uses covers to conceal the connections, corners and any other joints. These are effectively 'blank' pieces of skirting that are hollow and clip over the front of the ThermaSkirt wherever there is a corner or joint.

The BM2 and BM3 profiles use powder coated stainless steel covers, with all other profiles LT, TS and OG use injection moulded plastic.

For internal corners, begin by pushing the top clip down into the skirting's top channel. Once this is in place push the bottom clip underneath the bottom edge of the skirting. You will hear a 'click', letting you know that the cover is in place.

I required a special cover unit for the patio door reveals, seen in picture 2. As you can see in picture 3 and 4, the external cover has been notched out for the Deco Threshold kit. Obviously these aren't a standard piece, but you can either cut the covers yourself with a hack saw, or pay for DiscreteHeat to make a special cover piece. You need to send them some dimension details and ideally a picture, and they can make a particular cover to order.
These are fitted in the same way. Top clip and then bottom clip. As you can see in picture 5, I use a crowbar to wedge the skirting up slightly, which allows you to get the bottom clip under more easily. Once you remove whatever it is you are using to wedge up the skirting, it will drop back down to sit on the floor.

Push the remaining top strip into the skirting behind the covers. Picture 5 shows using a small screwdriver to get the top strip in properly as this can be a little fiddly. Picture 7 shows the finished result.

Deco Threshold Covers and Centre Strip

When fitting covers to the deco, make sure you cut the black plastic off the stainless steel clip show in picture 8, this isn't currently in the instructions but I find that when its cut out its far easier to fit the covers.
Push the covers into position locating the cover into the centre channel. Once the cover is fitted, overlap the centre strip and cut back to so that the overlap is approximately 10mm. Then push into the centre channel and slide under the cover. Picures 9-11.

We're almost there.

Step 11: Finally- the Big Reveal

Once the skirting is fitted, up and running, and your covers and top gasket are fitted you can take the protective film off. All the ThermaSkirt lengths come with a plastic protection on them. This simply peels off revealing the finished ThermaSkirt system.

Stand back and enjoy what you've done. After all the systems I have fitted I am still surprised how good it looks and how well it works. There's far more involved than simply hanging a radiator on the wall, but you can take a real pride in your work.

Thanks for Reading! If you have any questions let me know and I'll do my best to answer them.