Has anyone used this or knows if its any good: Spray insulation into rafters?

M

Muffinb

Registered User
Messages
175
Just wondering if anyone has used this or knows who supplies and sprays it? Thinking of it for the rafters for our apex roof as we want to plaster the ceiling leaving as much open space up the the apex shape as possible, any info would be fab.

Thanks
 
Have seen it on US based DIY shows but not here.... it is being distributed in Ireland by [broken link removed]
 
Hi Muffinbe! This product is generally used for the dual purpose of insulation and slate/tile stability. Sprayed on in multiple layers, if the average thickness is 100mm then it would be a brilliant insulator. Personally, I've never seen more than 30-50mm. Go to Yellow Pages under "insulation" and you will be snowed under.
 
I don't like it, for a number of reasons- it's generally proposed as a solution to slate slippage due to nail fatigue/ corrosion of fixings on older roofs. Looks great in principle but if you get a leak (via a cracked valley, cracked or loose slate etc) water will find its way into the roof space and will be concealed behind the spray on insulation where it may go undetected for years, until timbers rot and extensive damage has occured. Secondly this material does not allow your roof timbers and the roof space in general to breathe and unless you take appropriate alternative steps to ventilate the space you may have problems with condensation and mould in the roof. Any product worth using should be a BBA or Irish Agrement Cert. approved.
 

Thats a valid point - which a builder pointed out to me lately -it is vital that this is applied correctly allowing for air circulation other wise it will lead to problems. It is just like anything else in that manner - OK if applied correctly.
ninsaga
 
Thanks for the info, Thats very interesting about the ventilation aspect, would never have thought about that, at least with boards or fluffy stuff oyu can see water getting in too and some air will always circulate.

Kinda wondered why it was not used more, thats probably the answer!

I think well go with the standard stuff!

Thanks again
 
Well don;t just take our word for it.... ask the expects & get their opinion also.

ninsaga
 
First off, there's a company called Insulite that does spray-on polyturethane insulation which is different to Icynene (by the by, Icynene will probably have IAB certification before too long).

With the polyurethance insulation, you have a closed-cell structure so it can be applied straight onto the felt because once it you have it over 25mm ventilation isn't much of an issue because there's very little chance condensation will be formed.

However, what some people don't realise is that applying it between rafters is only a good idea if the attic is to be used as a living space. Otherwise the attic should be insulated at joist/ceiling level so as to keep the heat below the ceiling.
 
Yeah our roof wll be an open type apex if I am describing this right, When we look up to the ceiling will will see the apex of the roof shape, does that make sense??

Hard to know what to do really, will check out the companys and see what they say.

Thanks all
 

I know what you mean. I'm not entirely sure what would be above that but just insulate at ceiling level where possible. Otherwise, the heat will leak out through the ceiling to where it's no use....that's if there's a gap between ceiling and roof....if that makes sense
 
Mod's note: Please read the .
 
Last edited by a moderator:
You should also ask if they can do U-Value calculations for you.
 
Ok... my advice, compare technical data sheets from various inuslation companies, they might claim their products are all completely different, but you can verify that through their TD sheets (more often than not the TD sheets are exactly the same). Look at R-Values or K-Factors. K-Values are easier to be sure of as R-Values tend to get confused as different companies use different units of measurement.
 
I recently used closed cell sprayfoam to a depth of 150mm in new build dormer, obviously enabled me to achieve insulation levels required but more importantly airtightness in roof and between wall plate and roof. Will know how effective when the winter comes, but there have been some windy days recently and not a breeze in the dormer or crawl spaces.
 
we are using it in our poroton block house which by the way is turning out fantastic.we are placing 25 mm kingspan between rafters and then spraying with the icynene filling in between the rafters my builder tells me it will allow air to circulate above the kingspan and keep everything well ventilated,,,we are not going to put any insulation in the floor of the attic ,,,,,,,,,,,,,,,,are we ok with that,,,,,,,,,,ta
 
You must log in or register to reply here.
Menu
Log in
Register