Whether or not to remove internal plaster

[Herefordhouse]

Morning all.

I've posted here previously but have an update now i have more access to the property. Its an 1860's sandstone property with obviously very thick walls. The property has had next to no work done on it for the last 60 odd years so will need a full replumb and rewire. It has no insulation and has signs of historic damp but doesn't seem to have many issues currently (It was vacant for roughly 9 months before we acquired the property) . I've taken back some of the internal plaster and it is roughly 1 inch thick and applied directly to the stone. It appears to have used a form of horsehair, and came off very easily. The stone underneath felt dry, but i might also try getting back to the stone in other areas.

So my question:
A. Would you suggest leaving the plaster as it stands, with the view to potentially apply a form of insulation on top (for example aerogel as its thin and can improve the Uvalue by a large margin). I think the amount of space that would be lost in the room is negligible in comparison to the time, effort and money required to get it back to stone. I also don't know whether i would create more issues by removing the plaster!

B. Remove all of the current lime plaster so there is a clean slate upon which to redo the services and plaster. Potentially longer process but you then know its all up to date and know there's no nasty stuff behind your walls that may cause issues in the future.

C. Dont do any insulation but merely chase the walls for the cabling and then redecorate.

If you need any more information then plaese ask. All suggestions are welcome, many thanks!



C. Not bother touching the walls at all as the stone is thick, and simply chase out some of the existing plaster for cabling and then re plaster with lime over those areas.

Photos attached below, any and all suggestions are appreciated and if you need further information then please ask.

 

[paulc]

Aerogel is horrendously expensive - Like £250 for a 10mm thick 8x4 sheet. Compare that to £20-30 for a similar area of 20mm woodfibre.. Aerogel is great if you need to maximise insulation but do not have the space for cheaper alternatives.
Having done a few walls here, even in the smallest room, the loss of a few inches of floor space is not noticeable. So in your situation, I'd go for woodfibre or cork.

 

[Herefordhouse]

thanks paul, and would you suggest woodfibre in the walls as well.

 

[mardinor]

C

Leave it alone, except for repairing chases.
Internal insulation will make negligible difference, remove all interest in the historic plaster finish, and risks causing other issues such as condensation/mould unless you go the woodfibre/breathable plaster route.

Honestly, your walls are better than most by far

 

[Herefordhouse]

brilliant, thank you for letting me know. I will be able to do EWI on two of the external walls as theyre just a single brick skin, as well as update the roof insluation.

 

[aockenden]

Morning all.

I've posted here previously but have an update now i have more access to the property. Its an 1860's sandstone property with obviously very thick walls. The property has had next to no work done on it for the last 60 odd years so will need a full replumb and rewire. It has no insulation and has signs of historic damp but doesn't seem to have many issues currently (It was vacant for roughly 9 months before we acquired the property) . I've taken back some of the internal plaster and it is roughly 1 inch thick and applied directly to the stone. It appears to have used a form of horsehair, and came off very easily. The stone underneath felt dry, but i might also try getting back to the stone in other areas.

So my question:
A. Would you suggest leaving the plaster as it stands, with the view to potentially apply a form of insulation on top (for example aerogel as its thin and can improve the Uvalue by a large margin). I think the amount of space that would be lost in the room is negligible in comparison to the time, effort and money required to get it back to stone. I also don't know whether i would create more issues by removing the plaster!

B. Remove all of the current lime plaster so there is a clean slate upon which to redo the services and plaster. Potentially longer process but you then know its all up to date and know there's no nasty stuff behind your walls that may cause issues in the future.

C. Dont do any insulation but merely chase the walls for the cabling and then redecorate.

If you need any more information then plaese ask. All suggestions are welcome, many thanks!


View attachment 13233View attachment 13234
C. Not bother touching the walls at all as the stone is thick, and simply chase out some of the existing plaster for cabling and then re plaster with lime over those areas.

Photos attached below, any and all suggestions are appreciated and if you need further information then please ask.

I would live in the house through a full winter before deciding whether you want to insulate or not. It’s easy to say “ah don’t bother” in June… but your opinion might be different at the end of Feb.

For us, 2 nasty winters with cold, uninsulated, condensation-prone walls were enough to convince us to strip everything back to bare stone and get 4 cm of insulating lime render / plaster onto the walls.

 

[Stevers]

You have a quality unmolested 'smooth' Victorian home, so do no harm! Our home is the same sort of thing in a less favoured location. Although ours isn't listed, we have chosen to keep the house very original and there is a nice sense of continuity here.

We've made two 'energy conservation' interventions, one was to use adhesive V strips to improve the draught and noise proofing of our lovely old sash and French windows - this being cheap, surprisingly effective and completely reversible. The second, which has had a huge impact on liveability is to install the Drayton Wiser smart room level heating controls to our 1997 gas central heating system. It's magical, and for no extra cost we can maintain background heat throughout the house whilst targetting the rooms we're in with warmth through the day. This has made the house comfortable enough for my elderly mother to move in with us, and without having to keep her nice and toasty we'd be using less gas.

In our lit semi-basement which once contained a dry kitchen, a scullery and a pantry, I have a trickle vent permanently open and the air from this runs through the basement and up behind the fully lined alcove cupboards that I have installed each side of the old range fireplace - this has improved the feel of the basement rooms no end. If you have dry 20" stone walls as we do, then it's not worth wrecking period features and material to potentially introduce new problems. Our ground floor is very well ventilated and without insulation (it's where those alcove cupboards vent to); but that's why you need hard wearing fitted carpets in nice muted colours, and a really good quality underlay!

 

[Herefordhouse]

These are all sensible responses. Im torn as to whether to insulate at all at this point. The thing drawing me to insulation is due to the whole house approach. Seeing as we will have a new extension which will have to comply to current building regs I am worried about coldspots etc when you think about the disparity in insulative values. I will be improving the loft insulation and floor insulation. Then 2 walls are thick sandstone masonry roughly 450mm thick and 2 walls are singleskin brick with pebbledash render which is coming away, so will have to be replaced. So my thought was to do EWI on those two external walls whilst we are at it. Then most of the property has been insulated without any disruption, all that would be left is whether we internally insulate on the sandstone..

Would anyone recommend calcium silicate board? If im honest i hadnt thought about delamination, although surely breathability would stop any form of damp buildup.
Can you apply a layer of insulated lime plaster directly onto the old lime plaster as shown in the photos (wallpaper etc removed)?

For example - my current thought is to chase out parts of walls for 1st fix electrics and plumbing, then either apply an insulated layer ontop. So for example woodfibre board at 40mm thickness with 8mm of lime plaster ontop. or just apply a fresh thin layer of lime plaster for a clean finish.

 

[housewinnie]

I would leave it too if it’s dry. Ventilation is all the old house needs. Remember that if rewiring legally I believe you do not have to chase the wires in run them on the surface at least you will then know where they are.

 

[paulc]

I would leave it too if it’s dry. Ventilation is all the old house needs. Remember that if rewiring legally I believe you do not have to chase the wires in run them on the surface at least you will then know where they are.

But surface mounted trunking & cables look ugly and are only really suited if you are going for an industrial look. And as long as the cables are routed within prescribed "safe zones", you'll know where they are within a few inches.

 

[a twig]

Beauty is in the eye of the beer holder and all that, I really like the ranges of antiqued bronze conduit etc that is available for surface mounting these days - can make surface mount look quite attractive even in a typical residential setting

 

[larry]

Just to check my understanding of your plans, if you're doing EWI you definitely don't need to worry about IWI for those same walls.
However, for the remaining walls it surely makes the case for (breathable/natural) IWI even more important. Or maybe my mental model is wrong!

Wood fibre insulation here and thoroughly recommend.has made a blooming massive difference. We did 80mm but have solid brick.

 

[housewinnie]

Our old house is mainly all surface mounted wiring. Once painted you don’t notice it.

 

[Stevers]

All lighting circuits here (but not the ring mains) were surface wired, and were immediately chased in. In my 1997 state of ignorance and haste, all the above ground chases were filled by me with Thistle One Coat. That could have been a very bad thing, but has worked well even in a section of blown lime plaster in the semi-basement. To me any kind of authentic period look in a 'smooth' house, shouldn't have wires showing. I do have a couple of surface runs on some panelling under the stairs to the basement, but that's all in D shaped adhesive ducting. I also went for honest white when it comes to sockets and switches, retaining the ones (including lots of 1960s MK single sockets) that were already here.

 

[Kearn]

Leave well alone if you still have haired lime on there. Defiantly stop removing sections.

You say ‘very thick’ walls - that there is your thermal insulating mass, make sure it is dry so it is an insulator, not a wet conductor, and that’s that.

Chase and repair - hemp line pre bagged is an easy fix, and can go on much thicker than a standard base coat with minimal shrinkage, so can be applied like a daub to pack out holes.

Any internal attempts at insulation are a very expensive, unnecessary exercise - Dave the budget for where it is needed!