Options for insulating an old sandstone terrace

[Glesga Jim]

Hi all - first post! ??

 

I'd be extremely grateful to anyone who can offer me any advice ? I'm looking for some "explain like I'm 5" answers to some questions I have about insulating my newly-acquired 1920s end-of-terrace, which is (needless to say) built with solid stone/masonry walls.

 

 

 

 

I am thinking to perhaps externally insulate the rear wall, which already has some sort of rendered finish.

 

However, I doubt I can externally insulate the sandstone on the rest of the building so am hoping to add some internal wall insulation. The side of the building has old (unused) chimney flues as shown in the pictures. Don't be thrown off by the door in the interior picture - this is the exterior wall behind there ?

 

Onto the questions:

1. Does the internal/external approach I've described seem broadly sensible?
2. Do we agree that it's definitely worth doing internal wall insulation (even if I also insulate the floors and loft?)
3. (assuming yes); with regard to the old flues (which I guess are actually a 'cavity' of sorts?) what is the best strategy for insulating here?
4. What needs to be done to prevent damp issues? Esp. during the winter months, when the sandstone will be cold and wet
5. I've seen products like 'StrormDry', which claim to provide long-term waterproofing of exterior surfaces. Are these legit and effective and would they be of any help in reducing the chance of damp issues?

 

I expect a lot of disruption here of course so I'd generally prioritise 'better' solutions over mimimising disruption.

 

Thanks for reading! ??

 

 

 

Edited December 12, 2021 by Glesga Jim

[saveasteading]

13 minutes ago, Glesga Jim said:

built with solid stone/masonry walls.

 

 

Insulating externally will be expensive and very difficult. It will affect the roof, drains, window: everything. So I think the cost kills the idea.

 

Loft is easy and cheap so use lots of good quality mineral wool

 

Floor: If timber you can lift the boards  and insert insulation between the joists. (You have lots of headroom so you could feasibly insulate over the existing floor, but it will probably make the doors too low.)

 

Walls internally.

It would make a mess, but perhaps do this gradually if ever you have to strip a wall back for other reasons. It is probably lath and plaster, but that looks like good condition and you wouldn't want to strip it only for insulation.

If covering  any floor areas put down underlay with carpet,  but also foam board under any tiling or vinyl: even 10mm makes a big difference.

 

Are the windows double glazed?

 

In order of benefit

1. do the loft

2. Draughts

3 Windows

4. Floors

5.  bits of improvement when appropriate.

[Glesga Jim]

Cheers @saveasteading - thanks for that ?

 

Windows are single-glazed and will need to be replaced.

 

All floors will likely be lifted anyway so I imagine it's no-brainer to insulate while this is happening?

 

Attaching excerpts from the EPC if this at all useful for context.

 

 

 

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Edited December 12, 2021 by Glesga Jim

[SteamyTea]

Cant really add to what @saveasteading says.

As insulation is going to be a challenge, unless you want to loose a lot of internal area, focus on airtightness.  If you are eating ll the air in the place, then every 15 minutes it is leaking out, and you have to heat it all over again, it is going to be expensive.

As you do not seem to have very large windows, there is not much to be gained there, except making sure they are fitted properly and air is not getting between the walls and the frame.

The ground floor is probably the one area to have a serious think about, if there is a void underneath it, then you need to properly insulate but still allow for air movement.

 

The basic rule with insulation is 'the thicker the better'.  Why the thermal conductivity has the units W.m^-1.K^-1.  You cannot control the temperature, as that is weather dependant, so all you can do it pick the lowest k Value and put as much as you can on the walls, floor and ceiling.

 

k Value = W.m^-1.K^-1

R Value = l / W.m^-1.K^-1, where l is thickness of insulation.

U Value is 1 / R Value, and has the more understandable units of W.m^-2.K^-1