How Much Insulation Do I Need - UPDATED Building Regulations

How much insulation do you need in your floor, walls and roof? Since June 2022 the building regulations changed in the UK, now requiring higher U-values, meaning thicker insulation. I get straight to the point and go through each element, telling you exactly what you need. Let me share with you what I've learnt over my 17yrs in construction. The failure to plan is planning to fail, so why not let me help you. If you have any questions I’ll be happy to answer them.

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[davejohnston]

Thanks for providing such a clear guide. It was bad enough for me as a BCO in 1983 to get builders to put 25mm jablite in the cavity but 150mm cavities is a whole new ball game!

[petermurphy]

Really helpful, thank you. Fully explains the spec on my architects plans for a loft conversion starting soon. Everything you list matches his specifications eg 300 mm of mineral wool in the roof void; two layers laid at 90° to each other. Spot on; great help.

[damdamdam]

That is the simplest most straightforward explanation on insulation required .
QED.

[onanysundrymule]

Next edition regs will call for the whole roof void and the second floor to both be packed full with insulation material, habitable occupation to be on the ground floor only!

[whalehunter]

Over hang your roof joists and notch them out to create a shallower soffit area for smaller facias.

[chriswild]

Thank you this was very helpful
The embedded energy and sheer volume of chemicals in these products must be enormous and the future disposal of these items at the end of the buildings life is going to be a problem in the future

[davidflavin]

Great video. Really helpful. Im prepaing for a self build. I'll get an architect and some labour for carrying etc but the rest I'll do myself over 18months.

[ryanball]

Hi! Great video. I have a detached (new build) pitched roof garage I am looking to convert to an office. If I create a cold roof, would I still need so much insultation? My rafters are only 70mm deep, so not sure how I do it, especially if I require a 50mm gap...

[bikerchrisukk]

I have not had it confirmed if OK, but I have done warm roofs where the osb/pir/osb sandwich just overhangs the wallplate, makes for a less tall fascia of just the 20+20+150

[scottwilson]

I understand the requirements for renovations are lower, and that there are some exceptions where meeting them would be impractical? How is that decided? For example insulating the interior of an older pitched roof with only 70mm rafters, so very little room for an air gap. All below the rafters would reduce height substantially. In such a case, would thinner insulation boards be acceptable?

[GianniPalmiero-se]

Hi, really useful video but can superquilt be used with celotex for pitched roof? I would save at least 50mm and works out cheaper?

[NIIS]

Hi there, might be a silly question but we're planning on doing a traditional suspended timber ground floor. Is there any regulation on insulating between joists? All I know is I need to leave 150mm gap between ground and bottom of the joists.

[jonpenney]

Hi, on the solid floor detail at 1:16, shouldn't the cavity wall insulation continue further down into the cavity, as it looks like there will be a cold bridge due to the lack of overlap between the wall and floor insulation?

[stuartibbotson]

you smashed it ... Brilliant thank you spot on video

[davideyres]

Does the cold flat roof need these requirements when replacing ceilings or replacing the roof covering? It’s impractical for me to add 50mm underneath the joists as this will reduce the ceiling height by 50mm and they are already very low. This seems somewhat draconian requirements given the restrictions of the roof that is already in place. For example if you had 150mm joists in the roof then 125mm of pir between the joists would leave you with insufficient air gap and adding the extra 25mm plus 50mm would put the ceiling height too low. It can’t be acceptable to force major structural change just to comply with insulation requirements that are going to give a marginal gain.

[davejohnston]

You mention a thermalite inner leaf. Does a dense inner leaf achieve 0.18 if pb on dabs is provided internally?

[gl]

Hi, great video thank you. For vaulted ceilings not in the attic (I have curved ceilings upstairs), my rafters measure roughly 70mm. How much insulation would you advise I need here with it being too short? For the attic can I install 400mm of rolled insulation on the floor instead of insulating between the rafters? I have a pitch roof with the black felt so I worry about condensation, etc

[graemestruthers]

Hi, i live in a 60's chalet style detached with cladding onf the top half at the front and coombe ceilings, so attic space behind some of the rooms. Just put a hatch in one of the rooms that had no access to the attic space to find (as expected) no insulation of this area. joists are 175mm, studs for the walls are 75mm. I was planning on 170 glass wool between the joists, then another layerbof 170at 90 degrees on top of this. In one of the other rooms fir the walls i used 100mm glass wool with netting to hold it in place. This time i was thinking 100mm glass wool with netting then maybe 170mm at 90 degrees to this again with netting ( this was cheaper option) or would i be best using 75 or 100mm celotex/kingspan, and if so will that be enough? Obviously better than the 0 that is there now!!

[jb]

Nice video! do you have similar one for new loft dormer conversion?

[kingofthetrowel]

Hi Ben, I was looking to see it you had any videos on windows upvc etc I have a scenario where the glass in my windows has blow and needs replacing, I’m seeing conflicting information if this job is notifiable or not. I understand that new doors windows need building control approval or a FENSA registered company to self certify. But for a simple double glazed glass replacement would it still need to be signed off by building control ? Any information would be great Ben 👍 as I will ring my local authority, but wanted to ask yourself first 👍👍