I live on the ground floor of a block of flats (apartments) in London, UK. Below me (basement / -1 level) is the block’s communal boiler providing hot water for the taps and hot water for the radiators in each flat.

Unfortunately my flat gets hotter than I would like. I rarely use the radiators and make the educated guess that it is heat rising from the equipment downstairs conducting through the floor (concrete slab / screed etc.). To illustrate I have record temperatures of 12 degrees Celsius / 45 Fahrenheit outside whilst 26 degrees / 79 Fahrenheit inside my flat with radiators off. I am trying to address the issue at source with the block’s owners / management however a year on little movement.

As part of renovating the flat I am replacing flooring with an engineered wood floor. It feels that I may as well try and add some thermal insulation whilst doing so.

On this forum I have seen someone refer to insulation in issues of conduction being most effective when between the heat source and the conductive material / layer. In this instance this would be to insulate the ceiling downstairs in the boiler room. There is already some insulation down there and I will continue to press the issue for a more / better insulation.

However, I would be interested in opinions on if it is worth me insulating my side?

I will use a damp proof layer / vapour layer between the insulation and the chipboard / engineered wood floor.

One concern I have is could it make the heat issue worse in my flat?

Many thanks

  • 1
    Welcome to sustainability.SE! This has the makings of a great question for the site, but it needs a bit of editing. Have you taken the site tour? I'd recommend cutting out the non-relevant bits ("Found the site...", "I had asked a question..." etc) to bring the focus to the question and the relevant information. This will ensure that the answers will be as useful as possible, not just for you, but for others who may have similar questions.
    – LShaver
    Commented Nov 28, 2016 at 20:49

2 Answers 2


When you've got very little space to work with, as is often the case when insulating floors, it can be worth looking at more expensive insulation that has a higher insulation value. Yes, reducing conductive gains needs the same material as reducing conductive losses: you're looking for a higher themral resistance, i.e. a lower thermal conductivity, in each case.

Aerogels are more expensive than PIR, but you'll probably get better insulation for a given thickness. Something like Ultratherm aerogel flooring, or Thermablok aerogel floor insulation board.

If you've got a residents' management group, it might be worth talking to them about going to the management group together, to get them to insulate the boiler room. At the moment, because it's uninsulated, you're all losing out. You're all getting charged for all the wasted heat, after all. So it would be financially sensible to get the pipes in the boiler room insulated, and to get the boiler room itself insulated.

Thermal insulation should help with the sound insulation - particularly if they stop air transmission - i.e. convection losses.

  • Thank you for the suggestions. Last question on Vapour Control Layer / Damp-proof membrane. Do I need one (I think so) and where do I lay it? In a normal floor insulation scheme with the objective to slow heat transfer from the room to the slab understand it would likely be the first thing to go down, separating the slab from everything else (and condensation forming on slab). In my case I’m trying achieve the reverse, to slow heat transfer from below via the slab to my room and floor. Should I put a DMP / VCL above the thermal insulation and below the chipboard and engineered wood floor?
    – Dave
    Commented Nov 29, 2016 at 18:45

If you do a find (control-f) for "0.00" on this web page, http://www.engineeringtoolbox.com/thermal-conductivity-d_429.html, you will find that gasses have the lowest thermal conductivity. If you do a find for "0.02" on the same page, you will find that silica aerogel and foam are some of the best insulators. If the materials compress, they loose their insulating properties, so fiberglass may be a good choice because it will endure concentrated pressure such as refrigerators rolling across the floor and kids bouncing basketballs. Another factor is that doubling the thickness of insulation halves the rate of heat transfer. The cost of materials and installation may differ greatly between materials too.

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