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We have an 1890's victorian bungalow and are about to replace a failed back-boiler with a combi, this'll leave a fireplace to be closed up and an empty space where the immersion tank currently juts out - since most of the wall will need replacing I'm thinking of stripping the wall and properly insulating it.

Looks like part of the wall has been worked on already, so it's only part lathe and plaster, the rest actually sounds like plaster skimmed over wood when you knock it! We'll see. Still, it'll be messy, but we're tired of being cold.

From going up in the loft and looking down the walls it looks like they're constructed like so:
thick stone wall
2-3cm air cavity
1 inch square wood studs attached to floor and ceiling joists
lathe and plaster across the studs

Having read around these forums and elsewhere I'm thinking we can use something like Celotex 25mm TB3025 between these studs, and 27mm Gyproc Thermaline plus insulated plasterboard over the top (since the latter will be about the same thinkness as lathe and plaster there'll be no great change in the dimensions of the room).

Which leads to some questions:
1. Does this sound reasonable?

2. The existing studs are very randomly spaced (10inch, 13inch for the two I measured) which will mean a lot of cutting of celotex, plus studs not lining up with edge of plasterboard. Would it be wiser to replace the studwork? And what with?

3. Speaking of studs - these 1inch studs seem wayyyy to small for the 305cm high walls, are they actually likely to be fixed to the wall somewhere (and thus a cold bridge!)? Or does the lathe help to make the wall rigid enough?

Thanks in advance. :D

Lets start with the change of boiler?
Have you looked at the disadvantages of a combi boiler?
Do you understand that you cannot stand at the sink peeling potatoes with warm water running?
With a combi you have to run the tap full on to keep the boiler working.
Most of them only use 15mm hot water pipes, so they cannot deliver hot water to say two hand basins, or sinks and or fill a bath without one going to sleep waiting for the bath to fill, or more likely no water coming out at all.
Have you checked your local water pressure? If your mains pressure is low, then at times of high demand you may struggle to run a combi.

[quote="Perry525"] Do you understand that you cannot stand at the sink peeling potatoes with warm water running?[/quote]
Why would you do that?! We usually leave the skin on and just scrub anyway, but cold water, or a little warm water in a bowl is just fine.


[quote="Perry525"]With a combi you have to run the tap full on to keep the boiler working.[/quote]
Yes. That's the point, it only works when it's *needed*.


[quote="Perry525"]sinks and or fill a bath without one going to sleep waiting for the bath to fill, or more likely no water coming out at all.
[/quote]
I spent years living in a flat with a combi - and had a hot shower most days.

[quote="Perry525"]If your mains pressure is low[/quote]
It's not.

In truth we'd like something greener but don't have the capital - plus we need to insulate the house better. Any thought's on the questions I asked?

Its quite likely that the house has survived for the last one hundred years or so as you find it. So, the size of timber must be right?
You need to think of this room as a package.
How big is the room?
How much heat does it need for its size compared with similar rooms you've been in.
How much heat do you put in in kwh.
How long do you have the heating on for, how long do you think it should take to warm up with your present heating arrangement?
Do you turn the heating off?
Do you let the temperature drop right down or do you just set it back a couple of degrees?
If the heat input is reasonable for its size. Where is the heat going?
Start by finding all the holes and cracks and filling them.
Then look at the ceiling, walls and floor and decide where best to start.
Improving the walls, when most of the heat escapes through the window, for example may not be the best place to start.