Cavity wall insulation - what's the best type to get?

[buzzer]

We intend to get our 5 bed late 70's house cavities insulated. There seems to be different types of insulation available, being offered a bead type on the first quote....

what's considered the best and what's the advantages, disadvantages of the various types?

[Busamav]

My preference was blown fibre.

[Spudler]

mineral wool.

[A - W]

Which product has the best u-value? Then have a look at costs per metre square.

Settle on something that mets your expectations.

[buzzer]

Busamav said:

My preference was blown fibre.

What made you go for this over the other types?

[fatboy b]

I'd also make sure you can put it in too. Can't in my house - early 80's detached, though I'd probably not want it anyway.

[Spudler]

buzzer said:

what's considered the best and what's the advantages, disadvantages of the various types?

We use these people... http://www.markgroup.co.uk/products/cavity-wall-in...
They're about as good as your going to get.

[andy43]

Beware the beads. Probably one of the better insulators, but if you have new windows fitted afterwards...

[JR]

One that doesn't hold water.

[mattdaniels]

None at all. The cavity is there for a reason.

[Busamav]

buzzer said:

What made you go for this over the other types?

For one it has been around a long time now. It is basically a waterproof fibre due to it being treated , it does not retain water in any form.
I believe it is more likey to be a breathable material .

Better chance of getting get an even coverage with no voids , unlike the beads and the adhesive.

IF , I remember correctly it requires less frequent drillings than the beads.


I also do not like the thought of the cavity being filled with basically a solid sheet of polystyrene ,
any manufacturer, ie Kingspan / celotex , who sells boards for new cavity wall builds insists on retaining a cavity between the insulation and the external skin.

now waits for a specialist to come shoot me down

[Spudler]

Busamav said:

Better chance of getting get an even coverage with no voids , unlike the beads

As much as i hate the bloody beads, they are the most effective and better coverage out of the products on offer.
Mineral wool is prone to sagging in the cavity.
Im having a house injected in a couple of weeks with mineral wool, being a builder i know what a PITA beads are, hence i wouldn't
recomend them.

[Chrisgr31]

mattdaniels said:

None at all. The cavity is there for a reason.

That is my inclination as well. Modern houses are still built with cavities for a reason.

[russ_a]

Spudler said:

We use these people... http://www.markgroup.co.uk/products/cavity-wall-in...
They're about as good as your going to get.

Well the previous owners of my current house (elderly couple) used these folks too. We are currently renevating the house and whilst the walls have the drill holes there is absolutely no cavity wall insulation installed even though they have paid for it and I have the 25 year certificate!

[Busamav]

Chrisgr31 said:

mattdaniels said:

None at all. The cavity is there for a reason.

That is my inclination as well. Modern houses are still built with cavities for a reason.

Up until last year, I have specced full fill cavity insulation using Dritherm for 20 years without a problem , which is similar to the fibre.