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Improving existing loft insulation 1881 end of terrace stone house

Postby mustangsally » Sat Nov 18, 2023 11:30 am

Hi All,
This is my first post so please be kind!
I’d like to improve the loft insulation in my 1881 built stone end of terrace house and would like to do it myself due to financial constraints.
The existing insulation is as follows:
- 270 mm mineral wool insulation over approx. 25% of loft floor.
- Less than 100 mm mineral wool insulation below loft boards over remaining loft floor area.
- 25 mm PIR in between rafters.
The simplest way would be to raise the height of the loft boarding, but due to a roof joist being directly above the loft hatch this isn’t ideal as it would further restrict the already limited access. The gable ends are currently uninsulated solid stone with an internal brick skin with broken bricks within the cavity so cavity wall insulation is not possible.
Am I correct in thinking that the lack of gable end insulation is making the PIR effectively useless? It would make sense in my novice mind to insulate the gable ends, but I’m wary of causing damp problems.
Any advice please?
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Simply Build It

Postby stoneyboy » Mon Nov 20, 2023 9:37 pm

Hi mustangsally,
Insulating the internal faces of your loft plus the installation of a suitable vapour barrier would be expensive. Suggest you remove existing boards, increase the mineral wool insulation to 270mm fitting stilts so you can replace the boards. In the area of the loft hatch remove the mineral wool and replace with pir insulated boarding so that you effectively have a lower area for access without compromising on heat losses.
Regards S
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