I live in a house from 1939.It has no cavity walls. At ground level the air
bricks are below the floor, but have had to have gauze over them to stop
wasps. Upstairs the bricks are near the ceiling of all the rooms and the
bedrooms chimneys had gas fires fitted up from the coal fires downstairs.
There is only one chimney, but its brought from two coal fires below via
alcoves eith an arch. Blocking up the chimneys downstairs meant that the
bedrooms had a howling gale from the gas fires to the air bricks. The gas
fires were removed or blocked off and a special anti resonant cowling fitted
on chimney to stop the whole lot sounding like an organ pipe.
New the problem with the air bricks was that the ceiling curved at the
edges where the eaves are, and the only flat bit was the air brick so the
normally wide slide to cover devices could not fit as the sides hit the
curved ceilings. Hence we have a number blocked and others with temp bits of
cardboard stuck over them.
Luckily the loft is insulated, as before we double glazed we used to get
icicles on the ceiling due, no doubt to an oil heater we had in the hallway
kicking out water vapour.
No sign of mould but my bathroom really needs a fan over the air vent in
the winter as a nice hot bath makes the walls run with water at the moment.
Brian

--

This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please
Note this Signature is meaningless.!
"David" wrote in message
...
Just a thought about the row of 1930s houses here (and others seen in the
past).

They seem to be generally built with air vent bricks near the ceiling in
upstairs bedrooms

I assume that this was for ventilation because most rooms had coal fires.

Again I assume that most of these have been blocked up over the years.
Certainly no trace of any inside our house.
I assume previous owners blocked them up.

All this got me thinking about ventilation.
With double glazing and draught proofing round doors and blocking up (or
not installing) fireplaces modern houses seem to have minimal ventilation.
This is generally a good thing to avoid heat loss, but can be a problem if
too much moisture is generated (drying clothes, cooking) with no air
exchange.

A classic problem which pops up on here from time to time.
Mould on the walls because people refuse to open windows because of lost
heat and the cost of heating.

I noticed today that the house is quite dry indoors.
RH of about 35%.
In the winter we don't leave windows open much, we cook a bit and dry
washing indoors.
The air outside is dry (cold air can't hold much moisture) so when it
comes indoors and heats up you have warm but very dry air.
This suggests that we are getting enough outside air in (doors opening and
closing mainly) to get outside dry air in and lower the internal RH.

Which brings me back to the start.
The original air vents are blocked up.
The open fires have been taken out (along with the chimneys) or blocked
up.
There is an air inlet by the wood burner but that is more or less it.
Which makes me wonder where the outside air is getting in.

We do have bathroom fans to take steam from the showers out.
We do use an extractor fan over the cooker which vents outside.
So we shouldn't be waterlogged.
Just wondering why there isn't more moisture in the house.

Oh, most of the suspended floors downstairs have been insulated
underneath, so not much air coming up through the floors I suspect.

Ramble, ramble, ramble.....

Cheers


Dave R

--
AMD FX-6300 in GA-990X-Gaming SLI-CF running Windows 7 Pro x64

--
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus