Hello,
Could anyone tell me the best insulation for an old farmhouse with a lot of beams!
Thank you very much as everything on the site is dated quite far back and I would love any new info if at all possible!
Best,
Lucy
Are you putting on a new roof, or is this internal?
We are going to āraiseā the existing roof two foot so we dont have to loose all the old beams, does that make sense?
Thank you for replying!
Roof spaces/attics, ceilings etc?. Do you still want to see some of the beams, are you looking for āflatā finishes or something mors rustic? Whatās the roof like?
Sorry, bit of a crossover. Big job raising the roof, at least it should be nice and flat when done. Breathable membrane over the joists, make sure the lower ends are sealed to prevent pests getting in. Rockwool between the joists, multilayer insulation under that fixed with vertical battens to the hoists and then plasterboarded to a suitable framework (i always find a wooden one works best in roof spaces) with an a ir space. Do the first fix wiring before plasterboarding. How do you intend to raise the roof half a metre ?
Are there 2 of you ?, see there appears to be a maura chambers too!
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I think multilayer insulation is not that efficient, and the aging of these materials is not known really. However, if you use it together with conventional rock or glass wool, I would say it is best to use it as a screen first below the roof, where it can reflect infrared of this potentially very hot surface (as a reflective surface - opposed to an air cell material like wool - it is more efficient when the temperature gradient is larger).
From a few experiences, the best is when you can afford to devote the attic to insulation. In warm regions, you will likely experience hot rooms otherwise.
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Fitted properly so it seals the space from drafts multifoil is very effective as a radiant barrier to reflect the heat out in summer. Sealing it to the walls properly is essential to prevent heat loss or gain. But even the very thick 30+ layers does not do as much as thick rockwool but together they are great, so they dont require so much space 150-200mm of rockwool + 30 layer multifoil with air gaps and a vapour permeable membrane under the counterbattened vented tile roof works really well on ours and shows enough beams to keep it interesting.
Longevity of multifoil? Not an issue, left test pieces out in all weathers for 15 -16 years before I used it, no degradation from the aluminium or plasticised aluminium types.
Degradation of the aluminium foil may not be evident by visual inspection. The efficiency relies on reflectivity, which is highly dependent on the surface state, and even tarnishing of the metallic mirror by dirt may affect it.
Well in short it didnt happen, just as bright as the day I nailed it to a board and left it out in full sun which of course it never gets exposed to.
Thinking how much energy you would have saved if you had used it 16 years earlierš
Hahaha, so many people said it would age badly, fall apart, oxidise and tarnish. But none of them actually tested them. It took a while for the re-roof project and being a holiday home very little if anything was wasted except some firewood in winter. Now if it had been a main house yes absolutely, its why I am so outspoken on such things.
Wanting to insulate the vaulted roof but put the ceiling in lower so it will be a flat ceiling. Thinking of insulating the vaulted area with the rigid insulation then the flat ceiling with thick insulation.
Not sure if itās a good idea leaving the deep void between the vaulted and flat ceiling.
Already done a different part of the house with just vaulted ceiling which worked well but the peak is 6 metres high and sides wall 2.5 metres. This is the colder side of house so thought lowering ceiling would help with heating rooms.
Any thoughts, advice greatly received .
Make sure there us some way to access the void in future.
Second that. Many years ago I had a chimney fire because unknowingly I was burning the old lambris which was still full of resin, well we had never had a real stove before. Anyhow some of the said tar had attached to the metal flue and caught, sending sparks down the chimney behind the stove. I panicked and rang the pompiers who came fast, ripped the stove and flue out and found some tar smouldering still butā¦ā¦.they needed to get into the roof space to check that the insulation and anything else was not smouldering either so lucky that we had put a trap door inside a bedroom fitted wardrobe with which they were able to send the smallest man up into and check. Without access and in the event of fire, the roof and probably the house would have gone whilst we were asleep. Learned valuable lessons that day and OH wasnāt even home from work when it kicked off. Gave the pompiers some bottles of whisky and wine for coming out.
Will you be putting in a floor to the vaulted area as Jane and Shiba have said for safe access? You will need to vent the space as rigid insulation is not air permeable so you would likely get a build up of condensation. Assuming you have tiles, whatās under the tiles in breather membrane category? Spaces need to be ventilated and more detail is really needed before advice is offered. It maybe better to insultate your ceiling well but leave the void to breath. Difficult at this level to see whatās there and how it would be working.
Janejones, Shiba and Corona ā¦ No the vaulted area will not be used. Iām beginning to think Iām adding more work than I need to do by thinking of doing this and sorting out access even more.
I was just going to lower it , no access, but from what you say think Iāll be virtually doubling the amount of work.
It might also look rather strange with the original area being vaulted and then walking into this part he house with lower ceiling height. Iām thinking I donāt need to over complicate a situation , when itās already been done successfully. Thank you for all the suggestions ā¦.. made me come to the best conclusion , just keep it simple. 
Yes, sometimes best not to interfere with something thatās already been there for ages and works well without causing unecessary condensation and ventilation problems that would be even more work and costs
Exactly, I had a day where I couldnāt do what I wanted in garden due to weather and I had too much time to think about things to do on house. Oh that would be a good ideaā¦ā¦. No it wouldnāt ! 