Recently made an offer on an old property, thick stone walls with part vaulted ceiling, getting a bit jittery about cost to heat. It’s mains gas, so not as bad as it could be, i’ve quite a bit of building experience, but worried the grade 2 bit will scupper any ideas of external insulation, internal insulation is a thought but also concerned about damp. Anyone on here had a similar situation and how did you tackle it? It’s in Wales if relevant.
Thanks in advance for any nuggets of wisdom. 🙂
and yes i am fitting a few wood burners.

If you can afford the space and cost then surely internal insulation is the way to go

timber-framed, insulated out-houses? (built against the house)

maybe only single-storey, but then at least the ground floor gets a bit warmer.

or, jumpers and hot tea.

Wouldn’t worry too much about adding insulation if the walls are thick and there’s no damp inside. Instead concentrate on blocking up any major draughts (you will never get rid of all of them and you shouldn’t be aiming for airtightness in an old property anyway) around windows/doors/floors etc and invest in thick curtains! You may also be able to add double-glazing or secondary glazing depending on the local conservation policy and officer’s view.
And yes, jumpers and hot tea.

Heat it up in autumn and you’ll be sorted for the rest of the year!

My nan has a house of similar construction, 3 stories (she’s 92!), walls about 2 feet thick of Cotswold stone and it’s always pretty toasty. Open fire downstairs is going most of the time though i suppose. She does have a blanket over her knees but i’m always alright in there with a tshirt on.

any cement on the outside of the building needs to come off and be replaced with lime, this should alleviate your damp concerns. then your only option is to insulate inside as grade II means you cannot change the outer appearance. where abouts in Wales are you? Im in Swansea and work in restoration so feel free to email me if you need help.

As Fionap – I wouldn’t worry about insulating the stonework, it will have a huge thermal mass which will iron out the daily ups and downs – get it warm, and keep it warm through the winter. It will also be great at keeping you cool through the summer. I certainly wouldn’t internally insulate it – this will mean that the thermal mass is continually cold in winter, and through the summer your rooms will be hot and stuffy. I’d leave the walls alone, just make sure that nothing impervious has been applied to them. It might be worth considering having the windows refurbished and draught proofed – Ventrolla are very good. Ensure that the roof is well insulated, and that the heating system is good.

Twinw4ll, you could ask the same question on Navitron – there’s some very knowledgeable people on there.

As Fionap – I wouldn’t worry about insulating the stonework, it will have a huge thermal mass which will iron out the daily ups and downs – get it warm, and keep it warm through the winter.

Eh? I take it neither of you have ever lived in a similar property…

Stone has pretty much zero warming abilities, unless ‘fired’ 😉

Start with the floor, then the walls/windows and roof/ceiling. All need as much quality insulation as you can afford (money and space).

Our walls are up to 3′ thick; then we’ve an air gap, minimum of 6″ of insulation topped off with plasterboard. Floor has more, and ceiling likewise.

Without insulation, it’ll be cold no matter how much money you burn in heating.

OP – I’m really not trying to have a dig here but did you not consider this before house-hunting and then buying? It’s just that running costs tend to feature highly on my list of priorities

b r – I’ve lived in plenty and restored plenty in my professional work. Whilst you’re right – stone is never going to achieve the same results as a modern build, it often performs much better than expected – especially if there is a rubble infill, which is often made up of lots of air, which breaks the direct heat loss path. Regardless, I would not advocate buying a Listed property with the expectation that you will be able to insulate through-out. If the OP is seriously considering insulating, read the listing documentation to see what is and isn’t covered, then speak with the local conservation officer, they may be receptive to the idea, but I doubt it.

I live in a 3 bedroomed stone grade 2 listed cottage. We have a single log burner in the lounge and a bit of additional insulation in the loft but that is it. Gas and electric is about £1,200 a year and its plenty warm enough.

Those who claim you don’t need to insulate are plain wrong. The thermal resistance of stone walls is low, as in very low, it’s nearly as bad as concrete so the wall would have to be 20m thick to meet modern requirements.

I’ve insulated a 30s house on the inside with a multi-layer insulator (aluminium foil, polyurethane and polyester) held in place with wooden battons and covered with wood or plasterboard. It’s R3 which is about the same as 100mm of Kingspan/Celotex or 120mm of recycled polyester – the alternatives.

I took some down to fit wiring after a year and there was no damp or condensation. I didn’t want to insulate on the outside as it would have left more thermal bridges around doors and windows and I was worried about the mild rising damp in the walls being trapped – a common problem in German homes insulated on the outside.

Ignore the advise on multi foils, they have been proven to have dubious claims, none can be backed up by independent testing. I’ve worked on several renovations like this. Some went uninsulated and while the running costs were a bit higher they were probably healthier and more robust than the half assed approaches.

I say half assed because the best I’ve seen was one that formed a timber frame inside the walls with a continuous vapour membrane from underfloor, up the walls and under roof insulation. I’d rate that as the best result however it was a major job and may be an issue on a listed building. Floors and roof were both replaced.

I say half assed because the best I’ve seen was one that formed a timber frame inside the walls with a continuous vapour membrane from underfloor, up the walls and under roof insulation. I’d rate that as the best result however it was a major job and may be an issue on a listed building. Floors and roof were both replaced.

This is pretty what my Dad did +20 y/o with our place. He had to use polystyrene as all that was really available, and whenever I’ve had to take any out I replaced it with Celotex (or equivalent).

One thing that really makes a difference with us is that we’ve no ceilings on the ground floor, just open floorboards above. You can feel the warmth coming through. Plus very open plan and always leave all (internal) doors open so every bit of the house gets warmth – no cold spots.

consider the posibilities that may exist around the building as well,

shrubs and trees can protect the house for cold winds for example and a pile of nicely chopped and stacked covered wood on the sunny side of the building will also offer some protection.

Wooden floors are and a very well insulated roof would probably be my top tips.

Fitted furniture can also be a good way to isolate cold spots without losing loads of space.

I did one wall in a room with 120mm of recycled polyester rated R3.05 and one with a 27 layer multi-foil rated R3. There was no measurable difference between temperature of the walls and they were both much warmer than the non-insulated walls so I did most of the house with the multi-foil except for one gable end (polyester), under the floor (120mm polyester) and roof (done first using 100mm crosed with 200mm fibre-glass – I really wish I hadn’t, it’s horrible to work with and is already losing its volume)

Multfoil:

Easy to integrate with the triple-glazed widow frames which it butts up to nicely – no thermal bridge.
50mm less interior space lost (it’s already a small house)
No chance of it slipping down (a friend used a thermal camera and realised the tops of her walls were no longer filled with glass fibre).

Recycled polyester:

A more ecological product.
springy so if you cut it a bit big it stays in place.
Not easy to hold in place on walls
Breathes

Kingspan etc:

Great until you want to fix heavy objects to the walls. You have drill all the way through to place anchors in the wall behind.
You have to cut accurately

Rockwool:

Good sound insulator.
Difficult to cut and hold in place but reasonably rigid

Glass fibre:

Foul to work with
Floppy, ages badly
Requires more thickness for the same insulation
Never again.

I have a grade II listed house, albeit in England, you need permission for internal changes as well as external and that includes the installation of wood burners. What you can do will be dependent upon attitude of conservation officers (some are unpragmatic zealots) and the planning committee.

Check out some of the info on the tyr-mawr website – breathable lime solutions, etc. Where in the UK are you?

Thanks for all the info folks, had forgot about Navitron, good call. The property is not in an exposed position, so this might help. Scotroutes, yes, running costs were quite high on our priorities list, but we viewed this place on a whim, a bit like the mystery house, liked it and let our hearts rule our heads and then made a cheeky offer.
Thanks jonah, if things progress may drop you a line, property is near Machynlleth.
Might have to put jumpers and thick socks on my Santa list. 😕

ah good, your out of my catchment, i guess i can give you free advice without shooting myself in the foot then 😉 i do have a general builder mate in Mach who is good if you are looking for anyone. he is used to working with lime etc

Stone cottage = traditional materials = lime.
Done my place in Wales (Pembrokeshire) in Lime and it works for damp. Battening out/celotex/plasterboard is a mold trap and you run the risk of health issues doing that.

If you’re down this way you’re welcome to take a look.

Rich.

Right, back to this on a proper computer. Randomly, we have some friends in Machynlleth who have just done up a very old stone house! They internally insulated with materials from Ty-Mawr linky which are breathable and finished with lime plaster. It’s worked really well for them, they pretty much use one wood burner to heat the entire house. From my own experience with a stone house, water-tightness and breathability are key, so making sure roofing, guttering, etc, are good and that pointing is flush and using a lime mortar. If the stonework is painted then ideally it should be with lime wash. Hope you get on well with it!

Not much point in buying a character stone cottage with bare stone inside and chucking plasterboard all over it .May as well buy a new place .My parents place is early Victorian and stone and that has been toasty for the 51 years they have owned it without bankrupting them

OP, have a look at the Historic England website. There’s loads of useful information on there about insulation etc.

http://www.historicengland.org.uk/advice/

Also find out exactly what the listing of the building is for. It could just be the external appearance of the building but there may be internal aspects that are listed too. Make sure you get on the right side of the local conservation officer as they hold the power over changes to listed buildings.

The problem using modern insulation is if the job is not 100% moist air will make its way to the back side of the insulation and condensate on the cold walls . This may not cause problems in the short 10-15 years but longer may become a problem. The way English Heritage and the like are doing it is using a wood fibre board then lime plaster , this way the wall remains breathable. Roof is done with sheeps wool and breatheable membrane. Did our roof last year and made a big difference to our uninsulated bedrooms,very nice to work with as well.
Lime Green http://www.lime-green.co.uk/products/lime-systems do the wall insulation. Sheeps wool from Natural Insulation http://www.naturalinsulations.co.uk/
Just remember “Breathable Breathable Breathable “.

How did your parents heat their place, Edric? It might not have bankrupted them but it probably involved squandering natural resources and green-housing the planet.

Some quality info in this thread, will keep you posted when/if the sale goes through, we’ll probably do a winter without as a baseline for the thermal improvements.

Good idea, here’s our gas consumption in m3

02 602
03 468 – roof insulated
04 503
05 514
06 490
07 359 – walls, floor etc. started
08 326
09 270
10 236
11 central heating removed

A wood burner and thermal solar panel replaced the central heating. Electricity savings through more efficient lighting and appliances have roughly equaled electricity used for water heating when it’s cloudy so our electricity use is still only about 1700kWh/year (our PV panels produce double that).

A wood burner and thermal solar panel replaced the central heating.

Eh, if you took out the CH, how do you heat other (without the burner) rooms?

If the living area and kitchen are heated to 21°C in the evening the other rooms area at 16-18°C with no heating. Madame likes a warm bedroom so I’ve put an old radiator behind the wood burner that thermo-syphons to a vertical radiator in the bedroom so that too will reach 20°C if we wish (but I prefer a bit cooler).

The Mach area is awash with people connected to the Centre for Alternative Technology (CAT) who are living in old buildings and have upgraded them to varying degrees of success. Keep asking around and you’ll find lime experts, natural insulation experts, building performance experts and even some hempcrete nerds. For the stonework, the work of Stafford Holmes is worth looking up. A real lime expert.

If the living area and kitchen are heated to 21°C in the evening the other rooms area at 16-18°C with no heating

Does that mean it’s cold in the morning?

I guess though it also depends on where you live, ie easier if you’re South Coast vs Scotland.

Your mum has a thatched roof that needs maintaining, and your dad is a sheep shed?

The house loses very little overnight, my 16°C-18°C range was 16°C before lighting the wood burner early evening and 18°C late evening at times of year when the minimum temperature in around zero outside. We’re in Pau, France. Winters are a little warmer than Cornwall, the other seasons much warmer. There are five to ten days in the year when there’s a hard frost and we light the wood burner in the morning or at lunch time in addition to the evening cook up.

We’re in Pau, France.

🙄

About 5-10c warmer than the UK across the year, so we’d need a lot more insulation/heat than you to maintain the same inside temps.

Pau is colder in Winter than some places in the UK. The average low in early February is 1°C, that’s 2°C colder than Exeter, but you wouldn’t be rolling your eyes if I said I live in SW England.

Pau temperture graph

Exeter temperature graph

Where we do benefit is that the sun is higher in the sky in Winter and the days are longer so the solar thermal and PV continues to work a bit in Winter.

Edit: I’ve lived in a few places near Aberystwyth/Aberaeron/Mach, they aren’t cold in Winter, just horribly wet and windy.

Pau is colder in Winter than some places in the UK. The average low in early February is 0°C, that’s 3°C colder than Exeter, but you wouldn’t be rolling your eyes if I said I live in SW England.

Er, I would which is why I asked.

There is a world of difference between where you are and the OP’s property in rural North Wales, or ourselves in Scotland.

Temps tomorrow:
Pau 13c to 20c
Exeter 8c to 17c
Chester 12c to 14c
Selkirk 8c to 12c

But we’re talking about heating in Winter. Check out Plymouth or anywhere on the West Wales coast for Winter, that’s 21 December to 21 March and Pau is just as cold if not colder.

Plymouth.

Pau is a lot hotter in Summer and a lot warmer today as your figures show, irrelevant to the discussion, as we a talking about the morning temperature inside our houses in the middle of the heating season. My house has to be better insulated than a house in Plymouth for the unheated bedrooms to stay above 16°C with no heating in the house between 22:00 and 17:00 the next day.

Edit: Even Islay in Scotland isn’t colder than Pau In February. It’s the effect of the Gulf stream. Check out places in eastern France, they’re a lot colder than pretty much anywhere in Scotland in February, and I’m not talking about alpine villages.

I bet it’s a lot wetter and windier in Plymouth….