Heat distribution around home

[charles]

and later, my house in Georgian (George Vian) and has solid walls.

[The Natural Philosopher]

Insulation unless its infinite, will not fix temperature differentials. My living room is SE facing and gets sun all day, its boiling in summer if I dont close the curtains, whereas my NW facing workshop is wonderfully cool

[Brian Gaff]

Well how big are the rooms and what is the output of the heaters warming them. Also of course which have north facing walls and how good is the insulation. One does need to take a lot of things into account. In answer to the questions, I doubt any of the quick fixes will work as once you have temperature differences you get draughts, like the one dropping from the window I have behind me now. Brian

[Andrew]

Not when there is a female who 'needs' 23C+

[John J]

The solution to that is a dummy (disconnected) thermostat, preferably with an audible click, for her to play with while the real one is out of sight.

[alan_m]

Most electronic thermostats have temperature correction adjustment setting to compensate for a thermostat being placed in position where the temperature may be lower/higher than the average room temperature. Set this to 4C compensation and the thermostat will still be operating at 19C whilst displaying 23C :)

[Martin Brown]

When did cavity walls become the norm?

And perhaps more importantly in areas where subsidence is a problem how does a wall with exterior cracks in it behave when the interior gap is filled with potentially wettable foam or shredded material?

Many properties in the former coal fields fit that description.

[SteveW]

I've been meaning to make my own. We have a timer/thermostat in each room, operating relays that control motorised valves. My plan (when I have the time) is to replace each timer/stat with a touch screen, PIC or AVR and an ethernet connection. One part of my plan is to have a selectable offset on the display, so that I can, over time, reduce the temperature a fraction of a degree at a time, while being able to show her that it's just as warm as last week.

[SteveW]

I don't know, but my mid-30s semi has cavity walls, while my parents' mid-30s semi, just 3/4 of a mile away, has solid walls.

It's been in for about 19 years and the one crack (between the house and the extension) has never given any problem. Settlement, not subsidence.

[The Other John]

My 1925 house has 2 cavity walls and 2 solid walls, don't know why unless it's to do with load bearing of the asymmetrical roof design - the ridge is not central.

[Theo]

I think inter-war period, as others have said.

What I'm not clear on is why. Cavity insulation didn't come along until much later, so it wasn't that. One possible reason is better damp proofing: you can have an outer skin that's subject to the elements, then an air gap to allow it to dry, and a dry inner skin. That's an advantage over solid walls where moisture can pass through.

Wet insulation isn't good insulation. I suppose wet material also has the potential for erosion by freezing.

But otherwise I can't see it affecting the structural behaviour of the wall that much? Obviously damp masonry walls are not going to do much for your thermal behaviour or interior decoration, but would they be inclined to fall down? Theo

[The Natural Philosopher]

And air gap makes a huge difference even without insulation

Definitely The outer leaf could get soaked, and water would run down at the worst inside to the DPC, and because the cavity was ventilated, would evaporate

I've lived in a house with solid single brick - 4" of brick and no insulation. You have no idea how cold that is and how much it leads to condensation.

Going to two layers of brick and an air gap is a massive step up.

[Andrew]

Do you live in a zone defined in the building regs (Part B?) where excessive horizontal rain is more likely ?.

If so I would expect the cavity wall to take the brunt of the weather.

A typical way to keep driving rain out of a house with solid walls was to clad the exposed walls with slate tiles. There are a couple of houses like this near me.

[Andrew]

The chopped rockwool and the cavity batts, used for cavity wall insulation are supposed to be treated with a water repellent.

The stuff that comes in rolls for loft insulation gets saturated very easily if you have a roof leak.

[The Other John]

Not to my knowledge and as we are in a row of houses separated by driveways horizontal rain is not a problem. The solid walls are NW and NE facing, i.e. the cold sides and the cavities are SW and SE facing, warm sides. There's no cladding or render on the bricks.

[Andrew]

Well most rain hits the south side of the house so maybe this was why they are cavity walls. When your house was built it was probably heated by coal so heat loss wasn't a consideration.

[The Other John]

Yes there was a fireplace in every room when we bought it in '82 but there's only 1 now. Central heating was installed in '75 but the people we bought from still used a coal fire!

[me9]

Depends on where and climate. Coastal towns first. In my home town most were cavity walls from late victorian times. When I moved to Teesside I was surprised to find houses from teh 1920s still with solid walls.

[Chris J Dixon]

I had a house in Leicestershire built in 1939 with solid walls. When I moved to my current 1970s semi, my gas usage plummeted.

Chris

[AnthonyL]

The stuff that comes in rolls for loft insulation get saturated very easily if the **** shed that you bought it had one end open to the elements. I had to unroll it and leave it to dry for nearly a week.