To insulate or not ...

[Anna M]

I am looking at renovating a 130yr old stone house which currently has lath and plaster internally. Two tradesmen have advised not to insulate and just redecorate but one has said rip out and insulate with kingspan. A friend who has been in a similar situation has advised that heating bills would be enormous. Obviously it would be cheaper and quicker in the short term but potentially expensive in the long term. Any advice welcome. Thanks.

 

[motorbiking]

I just redecorated a room with 9” brick and stripped back to brick adding 50mm of celotex and plasterboard. Huge difference. U value of over 2, to less than around 0.5.

you do have to make sure you foam up all the gaps to stop condensation

 

[Scarlet Pimpernel]

If it's a stone house, do you mean that there is lathe and plaster applied to the internal face of the stone?

If you have lathe and plaster (on timber) internal walls, you don't want to apply insulation to internal walls, you only insulate the exterior walls of the house.
How thick are the stone walls? Is there a damp-proof-course in the walls? Is there any cavity in the walls? How is the exterior face of the stone walls finished?

 

[JohnD]

I have lived in old stone houses in the Alps, where the Winter temperature can be -20C, that have been dry-lined with insulation, and the heating costs are very low and the interior is warm and dry. Old stone houses often have quite uneven walls, and the lining also enables you to have smooth uncracked plaster, with concealed cables and plumbing.

Some of them were externally clad, which is less disruptive but spoils the look of the building.

my neighbour has a mid-Victorian stone house with original L&P lining, and the heating costs are very high.

In England, stone houses are usually cold and damp, and expensive to heat.

 

[JP_]

Insulate.

You can always decorate to make it look nice and old again.

It's not just the energy savings, it will also feel so much more comfortable all year round.

 

[Mr Chibs]

Another yes for insulation.

 

[motorbiking]

The only thing I had to do is splice an expansion batten in to the window board as the walls are now thicker. I used foam plaster adhesive

 

[Diver Fred]

I'd say asking this fora is not the correct way to approach this; not 'cause of the knowledge on here but due to the lack of knowledge of your exact circumstances.

Bobby D has asked the pertinent questions, importantly does the property have a damp proof course and how thick are the walls. That will help to get the correct advise but I'd say you need to get advice from an independent building surveyor who understands buildings of that era and the sensibility of insulating.

Thick (18' +) stone walls are quite effective at insulating but you could be causing damp issues in the walls by airtight insulation.

 

[JP_]

could be causing damp issues in the walls by airtight insulation

Trickle vents on windows?

 

[Diver Fred]

Trickle vents on windows?

No - that won't necessarily solve the problem in walls that do not have a DPC.

 

[jeds]

I'm a bit confused by the description; stone house with lath and plaster internally. Are the internal walls lined with a timber frame? (with lath and plaster) Or do you mean stone house with lath and plaster ceilings?

 

[ReganAndCarter]

As Blair used to say - insulation, insulation, insulation. Or summat like that.

 

[Anna M]

I'm a bit confused by the description; stone house with lath and plaster internally. Are the internal walls lined with a timber frame? (with lath and plaster) Or do you mean stone house with lath and plaster ceilings?

Internal walls are lined with lath and plaster.

 

[StephenStephen]

Internal walls are lined with lath and plaster.

Hoping to clarify here...

When you say 'internal walls' do you mean the internal sides of the external walls (ie; the walls between the rooms and the outside)? If so, I think you're confusing people because those are called external walls.

Or, when you say 'internal walls' do you mean the walls between different rooms? In which case people are confused because why would you insulate them for heat?

 

[Anna M]

Hoping to clarify here...

When you say 'internal walls' do you mean the internal sides of the external walls (ie; the walls between the rooms and the outside)? If so, I think you're confusing people because those are called external walls.

Or, when you say 'internal walls' do you mean the walls between different rooms? In which case people are confused because why would you insulate them for heat?

‍ Total amateur here. The external walls insulation. Sorry for the confusion