The insulation is placed over the rafters and then a felt is placed on top.
Roof rafters 7 insultaion.
This roof type will require a breathable membrane like kingspan nilvent to be.
This method of installing roof insulation allows you to maximise the headroom by using a thinner layer of insulation beneath the rafters.
If you have an easy roof to vent and decide to go that route you could use mineral wool insulation between the rafters and beneath the vent channels.
The insulation can be placed between the rafters or it can be placed between the ceiling joists.
The roof will typically be insulated above the rafter line creating what is most commonly known as a warm roof.
In part 6 of this series on attic insulation we dealt with proper attic ventilation and how it goes hand in hand with proper insulation.
The battening and tiling is then fixed down over.
Utilising a pitched roof as a usable living space is an effective way to maximise the square meterage of a residential development.
Working on your knees in an attic for long periods of time can be very hot and tiring.
Modern u value targets mean installing insulation between rafters only is rarely a viable option.
There will also be kooltherm k7 pitched roof board between the rafters image credit.
Insulating a pitched roof between and below the rafters is a very common roof insulation choice particularly for retrofit and refurbishment projects.
You will be covered from head to toe in clothing and gear.
To create a warm pitched roof insulation such as kingspan kooltherm k7 pitched roof board should be fitted between and over the rafters.
For instance if the roof has 2 by 6 rafters and you want r 30 insulation which is standard in many communities you can add a 2 by 4 which will give you an 9 inch rafter space.
If 180mm is to be installed then 100mm board might be introduced between the rafters there has to be a minimum 25mm air gap between the insulation and the underside of the tiles or slates with an 80mm board running.
It allows insulation to be installed in a watertight roof either after the roof covering has been fixed on a new build or without disturbing an otherwise sound existing roof covering as part of a renovation.
If you choose or need to go with an unvented roof you would need either exterior insulation or a flash coat of closed cell spray foam first then you could round out the insulation package with mineral wool.
In part 7 you ll learn how to insulate the attic rafters.
The thickness of insulation will vary depending on the manufacturer s specification.