Last week we looked at how internal wall insulation works and how to choose between the systems. This time Roger fits it, start to finish, using two of them.
Most of the problems people read about with wall insulation come down to installation rather than the product. Get the detailing right and it works. Miss one bit and that’s where the mould starts.
📕 Free guide, put together with the experts at Ezy Fit
https://go.skill-builder.uk/iwi-guide
PRODUCTS USED
Ezy Fit Insulation Systems
https://go.skill-builder.uk/ezy-fit
Ezy Fit Green IWI Vapour Open Natural Fibre Hemp Insulation
https://go.skill-builder.uk/ezy-fit-green-iwi
Ezy Fit M IWI System Mineral Wool Insulation
https://go.skill-builder.uk/ezy-fit-miwi
PHS SD Variable Plus Vapour Control Layer
https://go.skill-builder.uk/phs-sd-variable-plus
Gerband 712 Internal Aluminium Foil Tape
https://go.skill-builder.uk/gerband-712
PHS Argo Plus (Multi-Tape)
https://go.skill-builder.uk/phs-argo-plus
Fortax 6400 Internal Airtight Adhesive Sealant
https://go.skill-builder.uk/fortax-6400
Ezy Fit offer free online training for contractors, audit your first job and supply the materials, which comes with a 25 year material guarantee.
Filmed at The Installation Assurance Authority (The IAA)
https://www.theiaa.co.uk
KEY TAKEAWAYS
– The insulation behind the studs is doing two jobs. It evens out an uneven old wall because it compresses slightly, and it stops air circulating in the voids behind the studwork, which is where moisture gets carried to a cold surface.
– Going into masonry, mark up and drill all your fixing holes first, plug them, then feed the screws through. Trying to drill straight through the studs into the wall behind will jam the drill once it hits the insulation.
– A vapour open system still needs a vapour control layer. Those are two different things, and a random sheet of polythene is not a substitute for a proper membrane.
– Run the membrane horizontally rather than vertically. You get fewer joints to tape, and every joint, every staple and every service penetration has to be covered.
– Timber studs are a cold bridge, but tested systems allow for it. At 100mm or more of timber it stops counting as a thermal bridge. Go thinner and it becomes one, and that’s where you’ll see a line of mould appear.
– In tight spots like meter cupboards, under stairs and fitted wardrobes you won’t get the full depth in. Use a thinner board rather than nothing, because any insulation there is better than a bare cold patch.
– Reveals need an insulated board bedded on a full bed of adhesive, not dot and dab, so there are no voids underneath, then mechanically fixed as well.
– The airtightness sealant never sets. That’s deliberate, so it moves with the building rather than cracking.
CHAPTERS
00:00 Why internal rather than external
00:39 The hemp system
01:27 Studs and backing insulation
02:29 Fixing into masonry
03:06 Cutting the boards
03:33 Vapour control, the bit people get wrong
04:36 Taping and stapling
06:42 Airtightness sealant
07:25 The mineral wool system
08:27 Setting out at 600 clear
08:52 Timber studs and cold bridging
09:54 Working in tight spaces
10:22 Window and door reveals
10:51 Full bed of adhesive, not dot and dab
11:47 Interstitial condensation
13:53 Fire rating and the 11 metre limit
14:11 The finished cutaways
Ezy Fit offer free online training for contractors, audit your first job and supply the materials, which comes with a 25 year material guarantee.
#InternalWallInsulation #SolidWallInsulation #Insulation #Drylining #SkillBuilder
