# Insulating pre-existing Vaulted Ceiling



## nai (7 Nov 2011)

Hi all,

A couple of issues here - I will be able to address one myself but I'm looking for suggestions on the other.

We have a room with a vaulted ceiling (30 degree pitch), 6" rafter, tiled roof, breathable membrane, vented soffits , Max height 12', room width 15', slope length approx 4' each side.

Originally insulated with Tri-ISO Super10 only.

12 Downlighters installed, pierced through insulation.

I've been meaning to address the insulation over the past couple of years but really want to now so I'm looking for suggestions 

I plan on replacing the Downlighters with Philips GU10 4 watt LED,s with a AU-FH150C collapsible hood over each. This will allow us to insulate right up to the hood if we can get insulation into the roofspace.


So I'm looking for thoughts on insulation - what are people's thoughts ?
I really don't want to have to take off the roof but may have to take part off.

Thanks.


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## lowCO2design (7 Nov 2011)

take down the plaster board, fit insulation between the rafters, install an air-tghtness/vb membrane including backers for the lights and then board, skim and paint. maybe even add an extra layer of insulation underneath the rafters

im fascinated to know who specified the foil stuff originally?


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## nai (7 Nov 2011)

Thanks for the reply but that's not a runner - would be much easier to take off the roof - I'm wondering whether there are more inventive methods of addressing this.

eg - blown cellulose insulation installed via existing downlighter openings.

My worst case would be to take off ridge and roof tiles, slats, membrane and address from top down.


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## Sandals (7 Nov 2011)

We have an all glass window sunroom with just fibreglass rolls between timber sheeting and roof, our own doing!!!  

Needless to say temp decreases on a cold night/early evening in winter.

Our quickest solution was to install a full glass unit of two side pieces and overhead fans with double doors. Find them fantastic as not only block off cold but actually made the sunroom more usable as now completely separate second sitting room off kitchen and dining room. Got them off a joinery company in Galway City.


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## lowCO2design (7 Nov 2011)

nai said:


> Thanks for the reply but that's not a runner - would be much easier to take off the roof - I'm wondering whether there are more inventive methods of addressing this.
> 
> eg - blown cellulose insulation installed via existing downlighter openings.
> 
> My worst case would be to take off ridge and roof tiles, slats, membrane and address from top down.


inventive  you need to retain a 50mm air gap between felt and insulation so pumping cellulose is not the answer.


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## nai (7 Nov 2011)

Well maybe not so destructive!! 

Does the 50mm air gap still hold in the case of a breathable membrane?


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## lowCO2design (7 Nov 2011)

nai said:


> Well maybe not so destructive!!
> 
> Does the 50mm air gap still hold in the case of a breathable membrane?


destructive  but you'd rather take of the slates than the plasterboard?

see p14 & 15 the issue imo is the blue inner line, otherwise known as 





> an air-tghtness/vb membrane including backers for the lights


(or intello type product) this stops both air infiltration but is also importantly to stop moisture migrating from the house into the insulation something that will not suit the roof structure even with a breathable felt. is your roof battened and cross battened above the breathable felt? can you recall the product name as some of them have specific requirements regarding the VB and double battening etc..


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