Ceiling insulation(1950s house)

DrPsychia

What's the most cost effective way to insulate sloped ceilings on first floor in an ex council house? All of the outer walls have these sloped ceilings due to the roof construction. In one of the attics I can see some slopes with fibreglass Insulation shoved down into the voids between the rafters, others don't. Unfortunately I can't easily access the rest of the attic to inspect yet because of the roof Cross beam supports which I would need to temporarily remove(the extension attic is tight to work in whereas the main attic is easy to move around). The roof is poorly vented at the eves. There's 100mm fibreglass insulation in parts of the extension attic but it's poorly done and not overlapped, lots of air gaps.

I was thinking to get some type of blown-in insulation/open-cell spray foam to fill the voids of the rafters and other parts of the attic but then I'd run into an issue of no ventilation and condensation which would cause mould and rot. I believe I would need vapour barrier between the living space and attic which I can't do without ripping out the entire upstairs ceilings, and I would need to somehow maintain a gap at the eaves and 50mm to the felt.

Another option is to remove the sloped ceilings and insulate properly with 100mm PIR(50mm space behind for ventilation) followed by a vapour barrier in front, draught sealing tape applied, then fit plasterboard and plaster. I'd like to avoid this option if possible as it will be very expensive because I can't do it myself, it's intrusive and hazardous due to the probable asbestos ceilings.

Another issue I have is that the ceilings between the ground and first floor have zero insulation, heat quickly dissipates upstairs. Again how should I solve this? Either I remove the floors upstairs and fit Sheepswool/rockwool, or I remove the ceilings downstairs and fit 100mm PIR between the joists? You're probably wondering why I want to insulate between two heated spaces? My logic is to keep the rooms at temps ideal for sleeping and downstairs very toasty.

I know one of the major issues with old houses is draughts and lack of insulation. I plan to install external wall insulation in the future but the costs are ludicrous at the moment. Then I'll seal the chimneys and try to do some draught proofing.

10-10-20

Any visualisation of these roofs? Having a hard time visualising an ex-CC house with first-floor sloped ceilings.

Calahonda52

where is this coming from:hazardous due to the probable asbestos ceilings.

ple p0st a few pictures

DrPsychia

https://www.boards.ie/discussion/comment/121261713#Comment_121261713

https://www.boards.ie/discussion/comment/121262290#Comment_121262290

Apologies for the slow reply.

Here's a pic of the sloped ceiling. It's like this at the front, side, and rear of the house. I fathom the reasoning why the roofs was built like this in the first place. I attached other pics of the attic and rafter view of the sloped part. Apologies for the bad pics of the rear of the attic, access is tight and I need to get a decent respirator to inspect it thoroughly.

Re the asbestos point: I was informed that for houses built in this era, asbestos was a common component used in plasterboard. I would need to get it tested to confirm.

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Calahonda52

pictures difficult to follow, rotate them properly and paste in rather than adding as attachments

Personally I would drop the ceiling internally and put rock wool insulation in the void with taped vapour barrier on the undersurface. Kill the source of condensation before it gets to the inaccessible areas.

Any other option is going to be very difficult to implement and very expensive. Nothing you do in the loft will address your eves detailing which is where all your condensation issues will develop.

This is a manageable job yourself, using a speedskim even makes the plastering doeable.

FJMC

Quilt insulation to flat part of ceiling within roofspace - take care not to block any ventilation paths between rafters where sloping ceilings start?

Insulated plasterboard to sloping part of ceiling within the rooms?

There are alternatives but possibly more extensive works - you could consider if you were doing a larger refurb.

F