External wall insulation-cables and pipes


solid wall insulation cables and pipes

External wall insulation -cables and pipes

Should you bury cables or pipe?

Every EWI installation will have at least some electrical or telecoms cables on the walls – it is to be expected. The questions is what to do with these items when you get EWI installed. You have a couple of options open to you – but it basically boils down to extending and putting the items on the outside of the insulation, or burying the items under the insulation. In this blog we are going to look at the pros and cons of each scenario, and the different ways this can be achieved.



Burying soil pipes and down pipes

We really recommend not burying any soil, waste or downpipes. Whilst it is possible to bury them in the insulation, there are numerous problems that can arise when this is carried out. Firstly, if there are any leaks in the pipes, or you need to get to the pipes for any reason, you will have to hack through the render to reach them. There will be a huge amount of patching involved as a result and a high cost to make good the rendered surface. Undiscovered leaks can cause the wall to become damp and case mould inside the home. Even if the pipes are sound, there is always the danger that someone could drill through the pipe in the future and damage it when they are fitting something else to the wall.

The easy answer is to make sure that whoever installs your insulation extends all plumbing, whatever the works involved. In some cases it might be necessary to bury small bends or runs of pipe, and in these cases they should be clearly marked and pointed out to the customer. Gas lines especially must be extended, as accidently drilling into them could be very dangerous.

Burying cables in the insulation

So if burying pipe work is a bad idea, what about cabling? There are a couple of different types of cables – electrical cables that carry a significant current, and telecoms cables that do not. Power lines should never be buried because the insulation can cause them to overheat and thus pose a fire risk. Telephone and tv cables could technically be buried, and this is the one type of cable that we sometimes offer to bury for the customer.


Why bury cables?

Some customers want their wall to look as tidy and clean as possible, with minimal cables showing on the wall. Thus it may be that the cables are buried in the insulation. This does not necessarily pose a problem, but you need to be aware of the following concerns:

  • It is easy to drill through cables when fixing the insulation. As you can see in the photo below, you can score the EPS to show exactly where any pipes or cabling are and therefore avoid drilling a fixing into the cables.
  • Cables could be damaged in future. Even after the insulation work is done, the customer may wish to attach an item to the wall and in doing so damage the cables embedded in the insulation.
  • Customer may need to reach the cables. This is not such a big concern as with plumbing, because you can always run a new cable, but if you need to get to the cable, you are out of luck.

Chasing your cabling is the answer

If the customer is very keen to hide the cables, but not bury them in the insulation, the alternative is to use a plastic cover which will conceal the cabling on the wall. Chasing is very cheap and highly effective, although it doesn’t quite make for the clean wall that burying the cables does.









  1. twryehedncbzdgc

    • Treble Glaze
    • 6.03.2017
    • Reply

    Should I go for EWI or treble glazing, I can only really afford one or the other.

Post comment