Notes from an eco house. (2025 Update)

In message <vl0hjd$26pnn$ snipped-for-privacy@dont-email.me, at 10:38:37 on Tue, 31 Dec

Sums need formulae, and lots of assumptions. I am of the opinion that the thermal inertia of a solid wall compensates for most of the lack of a layer of insulation.

In message <vl1be7$29akv$ snipped-for-privacy@dont-email.me, at 17:59:34 on Tue, 31 Dec

If and if. Possibly also "If the loft isn't insulated" too.

Huh? Why are you ignoring that. One answer is not to still have "big fireplaces", and either block them off or use wood (multifuel) burner design.

In message <vl0l2h$26pnn$ snipped-for-privacy@dont-email.me, at 11:37:53 on Tue, 31 Dec

Again, is that a single brick, or a 10" double-thickness wall?

or even 9" - as my walls are. (1911 vintage)

Of course - it's a pretty established method:

You might want to revise that opinion! Just 50mm of PIR can make a huge difference. I lined a north facing bathroom wall with it, and it went from the coldest to the warmest room in the house.

I'd use the term solid brick - so a 9" wall. I don't think any UK house has

Probably not unusual in small, old, extensions.

Oh dear.

You haven't a clue, have you?

No cavity= single brick

I've lived in three that did

Even 3mm of cork was enough to strop condensation on kitchen and bathroom exterior walls...

Blocking them off does nothing to reduce the conduction of heat from inside the room into the solid wall and out into the outside air. They are gigantic cold radiators both laterally through the gable end, and vertically into the loft and also up and out through the physical structure of the above-roof chimney stack. This is in addition to any passage of warm internal air up through the chimney.

A wood burner probably requires a lining anyway with granular insulating material filling the void between the lining and the original chimney which would not alter the effect of conduction of internal heat into, through and out to the outside via the structure of the chimney.

Removing them completely is a massive exercise even if it can be done by DIY, so the only alternative would be to completely box them in with insulated PB.

When did you last buy cork wall and/or floor tiles, the 1970's ?. That stuff is now quite pricey and doesn't seem to be so easily available (as it was 50 years ago).

You really have not got a clue have you? Loft insulation has no effect on the heat loss through a wall. Double skin brick walls, with no insulation have a U value of around

A quick calculation of one end wall, 5 metres by 8 metres, a typical house size: Double brick, no cavity, U value 2.1 - 2016 watts heat loss through that wall. Double brick, 50mm cavity, U value 1.4 - 1344 watts Modern wall with insulation, U value 0.16 - 153 watts.

So your house with a double brick wall will need between 8 and 13 times more energy to heat it to the same temperature. And now please try to justify your comment that leakage through the walls isnt significant. It is clearly a significant heat loss through that wall, but you have never noticed, as you dont know any better.

'Single skin' = no cavity. Could be single (4.5") or double (9") brick.

Thermal conductivity lambda-values: Solid brick: 2 W/(mK) PIR: 0.022

U-value = lambda / thickness

Thermal resistance R = 1/U: Brick: 0.5 per metre thickness PIR: 45

So the total resistance is:

Thickness brick (in metres) * R_brick + Thickness PIR * R_PIR

Single brick, no PIR: 0.114*0.5 + 0*45 = 0.057 Double brick, no PIR: 0.225*0.5 + 0*45 = 0.113 Single brick, 50mm PIR: 0.114*0.5 + 0.050*45 = 2.3 Double brick, 50mm PIR: 0.225*0.5 + 0.050*45 = 2.36

Adding 50mm of PIR reduces the thermal conductivity of single brick by:

Of double brick by:

Theo

and double brick - as this house was built

In message <vl6kch$3etii$ snipped-for-privacy@dont-email.me, at 18:02:57 on Thu, 2 Jan

I'll have a play with that later.

And then tiled over it? What about other rooms - a plasterboard layer too? If you want to hang cabinets, rads etc, I suppose you need really long bolts through to the wall behind.

How does one cope with window ledges, skirting boards, electrical sockets... central heating pipes I suppose need a double-angle adapter.

In message <vl6pb1$3fpnl$ snipped-for-privacy@dont-email.me, at 19:27:29 on Thu, 2 Jan

Some clue, because I've lived in houses of pretty much every kind of construction, and can compare.

Or shuttered concrete as my grandparents house was constructed so in Epsom. (17 Worple Road)

The ground and first floor were built like this. Grandpa used to amuse himself getting quotes from tradesmen to open up a new internal doorway between the back kitchen and the back room so that it could be used as a ground floor bedroom.

Quotes were always based on the assumption that being an internal wall it must be single skin brick or similar, while he knew it was 6 inch *really* tough concrete.

This was pre 1960, so none of those fancy power tools. Rawplugs were inserted into holes made with a device that had to be hit many many times with a club hammer while turning it in the hole. Unbelievable tough walls.

Even in 1993 when Grandma died, she was paying over £1000 a year gas bills to heat the place. Turn the heating off for only a few days and it took over a week to get the house back up to a liveable temperature.