Insulating attic - Unusual question

Pique

Hi All,

So my parents house is a 100 y.o stone built farmhouse. Basically the exact same as this one (sans the modern extension) LINKY

The bedroom ceilings are very high and the ceiling slopes up following the roofline until it becomes a flat ceiling/attic floor. (the red line in the sketch HERE  shows roughly what I mean. Hence the flat floor area of the attic is very small compared to the floor area of the rooms directly underneath.

The flat attic area is insulated with rockwool. However, as the highlighted areas are a larger area than the insulated area, it's like wearing half a coat.

How can I insulate the grey highlighted area? Is it OK to stuff rockwool or the likes down there somehow? Could I use styrofoam-type sheets and slide them down?

All opinions welcomed, thanks.

Calahonda52

are the soffits ventilated?
is there felt under slates?
how deep are roof rafters?
Best answer is to strop off roof, insulate above rafters, breathable felt, battens and counter battens.
ideas:
http://www.ecologicalbuildingsystems.com/Ireland

https://www.nsai.ie/about/news/publication-of-sr-542014-code-of-practice

BryanF

It’s important to leave an air cavity between existing slate/tile and any insulation, 50mm gap typically

There are no easy solutions here. If you dry line you risk cold spots where the insulation isn’t continuous, typically at wall plate level.

Pique

Removing the roof is NOT an option, even though it may be the ideal thing to do.

Rafters are 110mm. Yes it's felted.
I do not think the soffits are vented (but they're pretty fooked and will be replaced next year anyway). What are the implications of not having the soffit ventilated?
The attic is dry as a bone with no condensation or rot anywhere.

Am I reading correctly that there is 60mm of space that could be availed of?

Metric Tensor

Yes. 60ish mm available but extremely difficult to properly access without removing ceilings or slates.

The reason the attic is "dry as a bone" and the timber is in good condition is precisely because air can pass up along those rafters to ventilate the area.

Be very careful and err on the side of ventilation with this one. Shoving something down is unlikely to provide a quality insulation solution and is very likely to cause ventilation problems resulting in significant long term damage.

Pique

Would there be an opportunity to do anything while the soffits and facia are being replaced and work from inside and out at the same time or am I completely clutching at straws and just have to suck it up?