Condensation

[Colin1960]

My parents live in a bungalow with 9 inch solid walls. They have double glazed windows and central heating. As they are in their 80's the bungalow is relatively warm.
The walls in most rooms attract mould on the outside walls. When this is cleaned off the walls are almost wet. I assume this is condensation.

I was going to attempt to cure this by having airbricks installed to each room. My parents are against this because of drafts and insects! Just to test my theory, which basically increases ventilation, I was going to test it by trying to get them to open the windows more regularly.

Anyone have any better ideas ?

Regards,


Colin

 

[JohnD]

It needs ventilation. Some people have an aversion to ventilation.

//www.diynot.com/wiki/building:condensation_in_houses

 

[jeds]

One of the best methods of ventilation that is virtually unnoticeable is positive input ventilation. (PIV) There are several types that would suit your situation depending on how much you want to spend. Look up Drimaster or Nuaire etc.

 

[joe-90]

Ask if they'd prefer a dehumidifier. A damp atmosphere is very bad for the health of old people.

 

[Colin1960]

Many thanks for the replies, I am going to attack this in stages.
I am going to start by increasing the ventilation to the kitchen & bathroom. Which will hopefully remove most (not all) of the moist air.

Being a bungalow on one level I am also going to get them to close their bedroom & dining room doors and open the windows slightly. These are at the front of the house and seem to be the worst affected. I think the moist air from the kitchen & bathroom are 'hitting' these walls.

See how this goes before investing in further devices.

Regards,

Colin

 

[AronSearle]

You could try insulating the walls, either insulation to the inside of the wall, vapour barrier and plasterboard, or insulated plasterboard (making sure it has an integral vapour barrier).

Being a bungalow on one level I am also going to get them to close their bedroom & dining room doors and open the windows slightly. These are at the front of the house and seem to be the worst affected. I think the moist air from the kitchen & bathroom are 'hitting' these walls.

Nope, it's likely just that they are cold walls, and especially cold in corners

At 18C, and 40% humidity, a surface needs to be 4c for condensation to occur.
At 18C, and 50% humidity, a surface needs to be 7c for condensation to occur.

It wouldn’t be unreasonable for a 9” solid wall to be reaching those surface temperatures in at least some corners, those humidity’s and temperatures are not particularly high either, higher temperatures or humidity’s will mean condensation will occur on higher temperatures (so at 20c and 60% humidity, condensation occurs at 12c, a temperature that is pretty likely to occur on such walls).

Insulating the walls will increase the surface temperature, meaning you need much less ventilation to reduce condensation (less, not none).

Extra ventilation will fix the problem, partly because it makes the air colder, and partly because it lowers the humidity, but it does so at the cost of comfort and energy bills (a dehumidifier isn’t free to run either).

So the question to ask them is what do they want to do, do they want a proper fix, which will cost them some money up front (but save money over time and improve comfort), or do they want a quick fix, in which case get used to cold drafts, or run a dehumidifier 24/7.