pumped foam insulation

Mailman

Is pumped foam insulation a good option for a new build with regard to cost and effectiveness.

I'm thinking of a double leaf wall. (Sweeping Generalisation which I apologise for beforehand) Block layers either through ineptness or fecklessness can't be trusted to put insulation material in properly when building so let them just do what they know which is lay blocks and pump the cavity afterward before plastering.

Also does pumped insulation satisfy current/future building regulations or is it a less than ideal solution?

sinnerboy

less than ideal . if foam doesn't set right - goodnight vienna .

you are right about blockies and insulation

think poly beads pumped in BUT at 100 cavity you should dryline too .

Villain

I'm thinking the same lines as the op, I will have a 100mm block cavity and I was thinking of pumping the walls after rather than securing insualtion on site and then making sure it is installed properly etc.

I will be drylining external walls on the inside with at least one warmboard if not two. Anyone know which bead gives the best U Value?

Mailman

sinnerboy wrote: »

less than ideal . if foam doesn't set right - goodnight vienna .

you are right about blockies and insulation

think poly beads pumped in BUT at 100 cavity you should dryline too .

OK, so my view isn't far wrong then except one should replace foam with beads.

As for cavity width. If the cavity space is increased does that obviate the need for dry-lining.

I'm thinking that dry-lining requires a lot of labour and materials which can be avoided by getting the block-layers just to increase the cavity. I understand that this will require marginally more blocks/mortar and insulation.
Would it cut down project duration. I'm guessing it would take the best part of a week to a week and a half to dry-line all exterior walls for a reasonably large house assuming the contractor arrives on time whereas a blocklayer using a larger cavity space would still be steaming away.

sydthebeat

Mailman wrote: »

OK, so my view isn't far wrong then except one should replace foam with beads.

As for cavity width. If the cavity space is increased does that obviate the need for dry-lining.

I'm thinking that dry-lining requires a lot of labour and materials which can be avoided by getting the block-layers just to increase the cavity. I understand that this will require marginally more blocks/mortar and insulation.
Would it cut down project duration. I'm guessing it would take the best part of a week to a week and a half to dry-line all exterior walls for a reasonably large house assuming the contractor arrives on time whereas a blocklayer using a larger cavity space would still be steaming away.

Increasing the cavity width to 150mm has its own inherent problems.
Larger cavity means more wall ties and at closer centres.

Plus the insulation performance of a 150 pumped cavity will never come close to the performance of say 70mm PU with 47.5 cpb internal.

d2ww

Syd,
what does "cpb internal" mean?
Thanks,
d2ww

sydthebeat

composite plasterboard.....

its the insulation backed plasterboard

gsxr1

sydthebeat wrote: »

composite plasterboard.....

its the insulation backed plasterboard

great stuff for heat. But trying to fix skirting is a nightmare. especially if varnishing.. no one ever thinks of the poor carpenter:(:D

sydthebeat

gsxr1 wrote: »

great stuff for heat. But trying to fix skirting is a nightmare. especially if varnishing.. no one ever thinks of the poor carpenter:(:D

please expand on this, whats the issue??

gsxr1

sydthebeat wrote: »

please expand on this, whats the issue??

just jokeing.

Tis nearly impossible to fix finish timber through that much insulation and insulated slab, Especially the warped the bowed timber we seem to get here in Ireland.

Gunoprene adhesive is no good as it only sticks to paint and plaster.

Paslode don't make a pin over 2 1/2 inchs and 100mm+ screws look awful.


just the first problem that came to mind .Althought the energy saving out weighs my concerns.

a plumber or carpenter in the search for grounds can lead to a mess...

sinnerboy

agree . with dry lining you to need to plan for fixings

power points / light switches
rads
curtains
skirtings

hardwood grounds . need to be clever , pre plan use sparingly but as needed , dont want to loose more insulation than is absolutely necessary . behing elec boxes - min 25mm insulation - dont fix direct to block .

UNLESS - you forget the old cavity wall completely

If you use SIPs Timber Frame Poroton , ICF - always with insulated services cavity ( like dry ling which you insulated with fibregalss ) .

The insulation in the services cavity in these applications is a "brucie bonus" - over and above what SIPs / Timber Frame / Poroton / ICF give you . The insulation in the services cavity can be sacrificed in parts because the "real" insulation is in the system selected .

250882

I'm still not convinced that drylining is the way to go, what about the junctions where internal blockwork walls meet the external walls. Electrical sockets then become coldbridges as they bridge the insulation. You lose the ability to hang a tv bracket from an external wall and the strenght and rigidity of having a concrete wall is lost because its just a sheet of plasterboard as a finish. Your also reducing the thermal mass of the building which is something that I think is severly overlooked.
Better maybe to build single leaf 215/300mm block on flat and externally insulate and render. Air tight build in a traditional medium with an innovative twist and if you get the right firm (IAB approved) its guaranteed.

sas

250882 wrote: »

Better maybe to build single leaf 215/300mm block on flat and externally insulate and render. Air tight build in a traditional medium with an innovative twist and if you get the right firm (IAB approved) its guaranteed.

The big issue with external insulation is that it restricts (greatly) the design of a house. Its most suited to a rectangular 1 or 2 story without roof gable walls.

There also the issue of how you avoid a 215 - 300mm cold bridge between the external insulation and floor insulation. AAC blocks could be used but aren't wonderful insulators. Insulated rafts aren't common here.

sculptor

gsxr1, Have you tried fermacell or sasmox, pretty good for fixing to.
Sorry for drifting off topic.

gsxr1

sculptor wrote: »

gsxr1, Have you tried fermacell or sasmox, pretty good for fixing to.
Sorry for drifting off topic.

no. thanks for the tip . I will keep my eye open for these products

ollie30

i am going to use 25mm bonded insulation for drylining,taped and complete bonding fillets around all service penetrations to air seal then was hoping to fix fermacell over this as i hate plasterboard stud/drylined walls for fixing stuff to. then i was told fermacell is approx. 3 times more expensive than plasterboard, although some money can be recouped due to the fermacell fine surface treatment which is supposed to be a diy skim coat type of thingy,paintable in an hour or so. has great loadbearing capabilities but pricy.if anyone hears of anywhere its sold cheaper than rbp or somenoe importing from abroad please let me know.sorry for butting in just that the fermacell issue in my head at the mo