Finding the chase and cutting to it

While roof insulation can easily be considered a hat for your house, treating the ceilings and floors is a harder concept to articulate…

Just get on with it!

Indeed! Insulating the roof does so much to prevent you losing heat outside is obviously a good idea. The floor and ceilings are a harder concept to see as being beneficial. Yet they account for 10-20% of losses on the ground floor. Yet ceilings lose around 25% of heat loss from a room. This is all about maintaining the temperature zones between rooms that preventing losses into the outside world. Slippers are internal shoes…

OK but upstairs, we benefit from the roof insulation!

Not really, because this is an extra layer in many new builds. The ceiling of the ground floor is essentially the floor upstairs. A floor may be easier to get to, than a ceiling. But if we don’t do the ground floor itself, we are missing an opportunity.

It may seem insane to discuss insulation during one of the hottest summers in the northern hemisphere. But while the news talks about insulation making it harder to lose heat (perfectly true), the journalists do not say that good insulation can keep your house cooler for longer. Insulation gives heat stability.

Let’s start with upstairs.

Whenever you take your carpet up for any reason, take the opportunity to look at what you have. Like the roof, care does need to be taken. If you have some rock wool between the ceiling downstairs and the floor upstairs, that’s likely to be done in more than one place.

If not and you can unscrew the floor boards, this is not a difficult job. You simply run rock wool between the joists as per https://www.youtube.com/watch?v=UCGpRpKKGV8. Now, it is much easier to do this when the house is built. But there are other opportunities: any room being refurbished can have it applied.

Having the floor up for plumbing or heating pipe moves, is such an opportunity. In bathrooms, always install a water proof membrane to protect your wooden or steel joists. Just remember: unlike the ground floor shown in the video, internal mid-floors live inside the warm envelope of your house, so they don’t need external ventilation blocks or air bricks to stay dry.

If that’s really not an option?

There are other things you can do if that kind of insulation is not applicable. Any floor, any where can have an insulating underlay installed. https://www.youtube.com/watch?v=nwdbRTrtjQY shows one approach and there are many products out there, all with pros and cons. Do look for materials with a foil or reflective face, as this helps with infrared shielding. The higher the R-value, the better the performance is likely to be.

Using carpets upstairs can be much warmer than using wooden floors. If putting in a new laminate or wooden floor, do ask your supplier about the thermal properties of the materials you’re using and what their recommendation is for the underlay. Will they fit it? Will they ensure floor boards are sorted out, if you can’t get to the boards before hand?

If you fit the underlay yourself, do follow the manufacturers guidelines for ensuring there are no thermal or condensation bridges formed. Tape is often recommended to ensure rolls or blocks of insulation are as close as they can be. Stapling the material to the floor may not be suitable for that very reason, as metal staples can introduce a thermally conductive hole.

Remember, just doing underlay is not perfect, but can have an R-value between 0.5 to 1.5 m2k/W and save 30% to 40% in terms of preventing loss between rooms or the floor compared to uninsulated floors. This simple change can reduce localised heat loss down to roughly 7.5% in an upstairs room.

OK, will that underlay approach work for the ground floor too?

Yes, and it will help, but there are bigger opportunities if you are doing renovations. Again reducing your loss to 7-14% instead of 10-20%.

Every little helps, even just an extra layer of insulating underlay, if there is no opportunity to do anything else. Wooden flooring and carpets tend to have a 20 year life, so the insulation needs to last that long too. It may seem like adding extra to the bill, but you will get it back.