Solid walls

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PositronicRay

Original Poster:

27,012 posts

183 months

Sunday 19th February 2017
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Considering house move, it's a long time since I lived in a drafty old victorian house with solid walls. It has double glazing and a loft conversion (of sorts)
Am I likely to find it a bit of a mare to heat?

http://www.rightmove.co.uk/property-for-sale/prope...

yellowtang

1,777 posts

138 months

Sunday 19th February 2017
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I suspect it's going to be relatively expensive to heat. The problem with single skin brick properties is that the walls are quite thin, on a basic level this means less protection from the outside conditions.

The thin brick walls also have low thermal mass so they won't retain heat very well. (rubble stone 2ft thick solid wall construction has a much higher thermal mass for example)

From the photos it's clear that the walls are all modern gypsum plaster and emulsion paint, this means that they are not breathable, lime built solid construction walls need to breathe - if they can't, then the moisture levels will rise within the walls. A damp wall will be much more conductive than a dry one, hence a damp wall will feel cold to the touch. (Feeling dry to the touch inside doesn't necessarily mean the wall hasn't got too much moisture within it)

Plastic double glazing can exacerbate damp problems in old houses, do they have trickle vents?

Do you know the insulation spec of the roof?

PositronicRay

Original Poster:

27,012 posts

183 months

Sunday 19th February 2017
quotequote all
Ahhhh that would explain when I lived in a city centre victorian terrace, one particularly hot humid day a tide mark appeared on the inside 1m up from the floor.

Apparently many of the houses suffered similar that day, the explanation from a local builder was water trapped in the ground had nowhere to evaporate too.

No idea re the roof, trickle vents are in the window frames.

Edited by PositronicRay on Sunday 19th February 07:47

Gtom

1,609 posts

132 months

Sunday 19th February 2017
quotequote all
You have been give some duff advice there.

That house won't be a single skin, it will more than likely be a 9" solid wall.

What state are the rooms in? If they are due a bit of an upgrade you could do some internal insulating at that point, 40mm PIR board would make a world of difference. Couple that with a coating on the brickwork (secotherm or something like) and that place will be warm.

Looking at the reveals in the roof windows, there isn't a lot of insulation there either.


PositronicRay

Original Poster:

27,012 posts

183 months

Sunday 19th February 2017
quotequote all
Gtom said:
You have been give some duff advice there.

That house won't be a single skin, it will more than likely be a 9" solid wall.

What state are the rooms in? If they are due a bit of an upgrade you could do some internal insulating at that point, 40mm PIR board would make a world of difference. Couple that with a coating on the brickwork (secotherm or something like) and that place will be warm.

Looking at the reveals in the roof windows, there isn't a lot of insulation there either.
Not perfect but liveable (actually a bit less yellow than the photos)
The plan would be to do nothing (famous last words) for the 1st year or so..........

yellowtang

1,777 posts

138 months

Sunday 19th February 2017
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Two bricks in thickness I expect, so yes, not technically single skin. But by single skin, I meant one single wall rather than cavity construction - I suspect you knew this!

Equus

16,884 posts

101 months

Sunday 19th February 2017
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yellowtang said:
The thin brick walls also have low thermal mass so they won't retain heat very well. (rubble stone 2ft thick solid wall construction has a much higher thermal mass for example)
You're misunderstanding the concept of thermal mass.

It doesn't (in itself) affect the rate of heat loss.

It affects the rate of change of internal temperature in response to a change in energy input.

Think of it as the difference between speed and acceleration: a lightweight car will accelerate quicker for a given engine power, but its top speed and steady-state fuel consumption (which are governed by rolling resistance and aerodynamic drag, not weight for the car; governed by U-value, not themal mass, for a building) remain pretty much identical.

You can have a very low thermal mass building (timber frame or SIPs) which retains heat very well indeed. Too well, in some cases, in fact - they tend to suffer from excessive solar gain in summer.

jason61c

5,978 posts

174 months

Sunday 19th February 2017
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I wouldn't worry about it. It wont be that much more expensive to run.

yellowtang

1,777 posts

138 months

Sunday 19th February 2017
quotequote all
Equus said:
You're misunderstanding the concept of thermal mass.

It doesn't (in itself) affect the rate of heat loss.

It affects the rate of change of internal temperature in response to a change in energy input.

Think of it as the difference between speed and acceleration: a lightweight car will accelerate quicker for a given engine power, but its top speed and steady-state fuel consumption (which are governed by rolling resistance and aerodynamic drag, not weight for the car; governed by U-value, not themal mass, for a building) remain pretty much identical.

You can have a very low thermal mass building (timber frame or SIPs) which retains heat very well indeed. Too well, in some cases, in fact - they tend to suffer from excessive solar gain in summer.
I'm going to disagree with you there. I've been in the heritage restoration sector for 12 years, worked on all types of traditional construction and efficiency of old buildings is very much a hot topic right now.

The thicker the solid stone/brick wall, the greater the ability to store and release heat - thermal mass. Yes, heat input is part of that equation but not solely. In my house for example I have three bedrooms of equal size, two in the 17th century part with 24" rubble stone walls and one bedroom in the Edwardian extension with 9" Ashlar solid wall construction. The radiators in each room are the same output, the roof insulation is the same, all have insulated floors and heated rooms below and yet the Edwardian room is always cooler.

Yes, I fully agree with regard to high performing low thermal mass modern construction but that is not what we are talking about.


nyt

1,807 posts

150 months

Sunday 19th February 2017
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I have the same house construction. I'm not sure that I'd have another.
Our hallway is the full height of the house and in cold weather you can feel cold air falling down it like a waterfall.
It's enlightening walking into the extension (built to modern specs) when the heating has been off. The main house is freezing but the extension is relatively comfortable.

It's not spectacularly expensive to heat but you have to make sure that there is good airflow everywhere. Leaving a chest of drawers too close to the wall will eventually cause mould. Bathrooms etc need decent extractors.

I'm going to upgrade with some: http://www.proctorgroup.com/products/spacetherm. It seems possible to get very decent u vales with relatively thin internal insulation.


  • Disclaimer - my house is detached and in permanent shadow. I think even occasional sunshine would help.

Equus

16,884 posts

101 months

Sunday 19th February 2017
quotequote all
yellowtang said:
I'm going to disagree with you there. I've been in the heritage restoration sector for 12 years, worked on all types of traditional construction and efficiency of old buildings is very much a hot topic right now.

The thicker the solid stone/brick wall, the greater the ability to store and release heat - thermal mass. Yes, heat input is part of that equation but not solely. In my house for example I have three bedrooms of equal size, two in the 17th century part with 24" rubble stone walls and one bedroom in the Edwardian extension with 9" Ashlar solid wall construction. The radiators in each room are the same output, the roof insulation is the same, all have insulated floors and heated rooms below and yet the Edwardian room is always cooler.

Yes, I fully agree with regard to high performing low thermal mass modern construction but that is not what we are talking about.
You can disagree all you like. Your knowledge of building science is clearly woeful. Thermal mass has a very specific meaning, and it's not what you think it is.

A 24" solid wall has 267% the thermal resistance of a 9" solid ashlar wall on account of being 267% of the thickness (actually, rather better since there are more voids in it that aid the insulation), so it offers 267% of the thermal resistance. That's nothing to do with thermal mass though.

If we're having a pissing competition, I've been designing buildings for about 35 years, and am/have been a Director of an architectural practice, a manufacturer of low energy timber frame and SIP buildings, and a region of a major national housebuilder.

I know the difference between thermal resistance and thermal mass, I assure you. wink

PositronicRay

Original Poster:

27,012 posts

183 months

Sunday 19th February 2017
quotequote all
nyt said:
I have the same house construction. I'm not sure that I'd have another.
Our hallway is the full height of the house and in cold weather you can feel cold air falling down it like a waterfall.
It's enlightening walking into the extension (built to modern specs) when the heating has been off. The main house is freezing but the extension is relatively comfortable.

It's not spectacularly expensive to heat but you have to make sure that there is good airflow everywhere. Leaving a chest of drawers too close to the wall will eventually cause mould. Bathrooms etc need decent extractors.

I'm going to upgrade with some: http://www.proctorgroup.com/products/spacetherm. It seems possible to get very decent u vales with relatively thin internal insulation.


  • Disclaimer - my house is detached and in permanent shadow. I think even occasional sunshine would help.
Thanks useful info. This one is south facing on the long side, and a semi so maybe stay a little warmer, if we buy, wife has been instructed not to dry clothes in the spare bedroom.

As an aside, what will the noise insulation likely to be from next door? Currently in a 60s semi which is okay but rather be in a detached house.

PositronicRay

Original Poster:

27,012 posts

183 months

Sunday 19th February 2017
quotequote all
Equus said:
You're misunderstanding the concept of thermal mass.

It doesn't (in itself) affect the rate of heat loss.

It affects the rate of change of internal temperature in response to a change in energy input.

Think of it as the difference between speed and acceleration: a lightweight car will accelerate quicker for a given engine power, but its top speed and steady-state fuel consumption (which are governed by rolling resistance and aerodynamic drag, not weight for the car; governed by U-value, not themal mass, for a building) remain pretty much identical.

You can have a very low thermal mass building (timber frame or SIPs) which retains heat very well indeed. Too well, in some cases, in fact - they tend to suffer from excessive solar gain in summer.
So the upshot is in winter you leave the heating on, just don't let the house get cold.

8-P

2,758 posts

260 months

Sunday 19th February 2017
quotequote all
Blimey some serious knowledge on this one!

Equus

16,884 posts

101 months

Sunday 19th February 2017
quotequote all
PositronicRay said:
So the upshot is in winter you leave the heating on, just don't let the house get cold.
Yup, basically.

If you want a rapid heating response, you want low thermal mass... but despite what Yellowtang would have you believe, that's a completely different thing to low thermal resistance, and doesn't mean that your house should be poorly insulated.

nyt

1,807 posts

150 months

Sunday 19th February 2017
quotequote all
PositronicRay said:
Thanks useful info. This one is south facing on the long side, and a semi so maybe stay a little warmer, if we buy, wife has been instructed not to dry clothes in the spare bedroom.

As an aside, what will the noise insulation likely to be from next door? Currently in a 60s semi which is okay but rather be in a detached house.
Obviously a semi would be a great improvement from an insulation point of view. I have a https://www.amazon.co.uk/Etekcity-Lasergrip-Non-co... and I can see a 3 to 4C difference in wall temperature where the (unheated) garage meets the house. A heated home would be much better.

9" wall are pretty thick, so I'd imagine that sound insulation would be pretty good. The walls may not be so substantial between the houses though. You'd have to check.

The only area that give a real problem is the hall. It has a massive external north facing wall that forms one side of the stairs. Hence the search for thin insulation material.


yellowtang

1,777 posts

138 months

Sunday 19th February 2017
quotequote all

Equus said:
Yup, basically.

If you want a rapid heating response, you want low thermal mass... but despite what Yellowtang would have you believe, that's a completely different thing to low thermal resistance, and doesn't mean that your house should be poorly insulated.
Again, nonsense - nowhere have I said that thermal mass equates to thermal resistance? Two different things. A sheet of foil backed foam insulation has bugger all thermal mass but a very high thermal resistance, which is ideally what you want. However, we aren't talking about what you'd ideallly have, we are talking about what OP would have in this particular house as it stands.

The thicker the solid wall the higher its resistance, but only marginally since stone/brick are quite conductive and hence poor insulators. More to the point, the thicker the solid wall, the more heat it can store and release back - thermal mass. Albeit not particularly efficient.

Equus

16,884 posts

101 months

Sunday 19th February 2017
quotequote all
yellowtang said:
The thicker the solid wall the higher its resistance, but only marginally since stone/brick are quite conductive and hence poor insulators.
Thermal resistance = thickness/conductivity

Twice the thickness equals twice the thermal resistance. Simple as that. 'Marginally' doesn't come into it.

Heat flows from hot to cold, in accordance with the second law of thermodynamics, not the other way around. The energy stored in thermal mass wouldn't be released back into the building unless the internal temperature dropped below the average temperature of the wall.

As I've said, thermal mass merely damps (attenuates) fluctuations in temperature.

C Lee Farquar

4,068 posts

216 months

Sunday 19th February 2017
quotequote all
PositronicRay said:
Ahhhh that would explain when I lived in a city centre victorian terrace, one particularly hot humid day a tide mark appeared on the inside 1m up from the floor.

Apparently many of the houses suffered similar that day, the explanation from a local builder was water trapped in the ground had nowhere to evaporate too.

[/footnote]
I know it doesn't matter to you now but the builder's explanation couldn't be right.

Damp takes months to rise up a wall. Water isn't trapped in the ground, it equalises within it's environment. If there were 100% humidity and no external factors, no water would evaporate.

However the symptoms are common and nearly always caused by residual salts from past dampness. These salts will absorb moisture quickly. On a humid day damp patches would appear.





kambites

67,561 posts

221 months

Sunday 19th February 2017
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Equus said:
The energy stored in thermal mass wouldn't be released back into the building unless the internal temperature dropped below the average temperature of the wall.
This is true, but the walls do provide a "damping" effect on the internal temperatures, both in terms of the night/day heat cycle and to a lesser extent over longer periods.