Suitable roll insulation for sub-floor

[Bertieeee]

I want to insulate the ground floor of my house from the void below and my plan is to do it with wool insulation held up with netting. This seems to be a fairly standard way but I'm struggling to find insulation that is actually rated for the purpose. Everything from the usual shops (MKM, Jewsons etc.) seems to be rated for lofts or walls or be boards. I don't really want to use boards as (a) it's more expensive and (b) from what I've found it's more of a pain to put up. Has anyone done this themselves and can recommend a suitable roll?

Thanks

 

[aveatry]

I used rock wool slabs which only need a couple of lengths of wire stapled across the joists to hold them up. Given rough sawn joists you can cut the slabs a tight fit and they almost hold themselves up

 

[Bertieeee]

Thanks for the info!

 

[Deluks]

It's advisable to fit a membrane underneath.

 

[Bertieeee]

I thought that if there was suitable airflow that a membrane wasn't required?

 

[StephenStephen]

I've done this, it works.

I'm curious why you want a rating for the purpose?

Using a membrane is a good idea because:

-A lot of heat is lost through the floor through simple air flow - a membrane can massively reduce this.
In terms of heat loss through a suspended floor, I wonder whether a membrane can make more difference than insulation.

-Warmer wetter air from the room can condense when it flows under the floor and cools. A membrane prevents this.

 

[StephenStephen]

Have a look here:

Search results for query: insulate under floor

www.diynot.com

 

[Bertieeee]

Perhaps I'm being naive but in terms of a rating I was under the impression that there was something different about the insulation depending on the location it was being used in. They seem to be advertised as 'loft' or 'wall' but there's very few which talk about a suspended ground floor. It does appear to exist (eg. Knauf Omnifit) but not available at the usual stores I'd go to, so I'd have to get it online. I assumed it was something to do with it being external-facing as opposed to inside a roof or wall. Can I just use anything?

Noted on the membrane I'll take a look, thanks

 

[Deluks]

Most people use loft roll, it works out much cheaper. Although not self supporting like the slabs would be, the membrane would support it. Get any old breathable membrane.