Insulation pitched roof help

nelliedee · 22 Sep 2009

Hi

We need to insulate a ceiling in a newly built kitchen. Above the kitchen will be a bedroom. To the side of the kitchen is a small pitched roof .
Is it very tricky to insulate ourselves? We are unsure where the air gaps should be! Are there any good diagrams anywhere on the internet as it is so much easier to learn from pictures.
We are paying for builder, electriction, plumber and plasterer and would like to try and do the insulating ourselves.

noseall · 22 Sep 2009

A conventionally insulated pitched roof, done using fibreglass quilt will require 150mm between the ceiling joists and 150mm above and across the joists, providing slightly above required minimum of quilt insulation, i.e. 280mm.

Venting the airspace that remains above this quilt can be achieved with either roof tile vents, gable air bricks, over-fascia vents or soffit vents.

If you choose to vent via the soffit or fascia then you will need to install eaves ventilators to prevent the insulation (between the joists) stifling the airflow.

The insulation is normally pushed down into the eaves so that it meets the wall insulation hence the need for eaves ventilators to allow the passage of air past this narrow part of the roof detail.

nelliedee · 22 Sep 2009

Our roof has breathable felt/membrane so does that help

noseall · 23 Sep 2009

nelliedee said:
Our roof has breathable felt/membrane so does that help

Only if the roof is isolated or that it is cut into an existing roof with similar breathable sarking membrane.

nelliedee · 24 Sep 2009

thank you

nelliedee · 20 Nov 2009

If we use fascia or soffit vents are we going to struggle as roof fascia and soffit are already built and fixed in place? Does this mean we need to remove fascia/soffit boards and install new ones with vents built in?
Are the eaves ventilators easy to fix in place? because our roof is already built I am thinking some of this work should have been carried out before the roof was finished

g xx

nelliedee · 20 Nov 2009

me again

I am just about to buy the fiberglass quilt and after reading the info on wickes site, the quilt I thought we needed to buy says, '' for diy use and not to be used on new builds''
Is there a certain type of fiberglass quilt we need? and what is wrong with the wickes stuff?
g xx

freddiemercurystwin · 20 Nov 2009

nelliedee said:
and what is wrong with the wickes stuff

Because its so sh**e it won't match that of a decent make like Rockwool and it probably won't achieve the minimum heat loss requirements building regs demand. The cheaper brands rarely confess just how bad their insulation is so leave the important info off and instead stick silly disclaimers on.

diynot

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Insulation pitched roof help

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