Constant pressure from air brick..

[John walter]

Hi all, hope all are well
I was wondering if could help me with a little issue that has arisen over past few days..
In my sons bedroom the wall has a air brick with a hit and miss vent on, which has been fine.. But over last few days it has had constant pressure blowing into my sons room as if someone was stood behind the wall with a fan, it is not windy so I have no explanation for this and when I go outside up near his room sounds like a boiler is running constantly and static from a TV and these seem to sound like the pressure circulating with the chimney breast.. We have no fires in house fireplaces bricked up.. Next door have got builders in and out and I'm thinking have they knocked something
Any ideas
Thanks

 

[Harry Bloomfield]

I haven't any better ideas to the cause, other than a change in the usual wind direction - it is blowing gently from the south at the moment. Perhaps the building work next door has changed their building profile to funnel wind more into the vent?

I guess it's a pre-1970's house, with the mention of fireplaces and wall vents? Wall vents were designed in to allow sufficient ventilation for the coal fires, they are largely unnecessary with modern heating systems and make rooms much colder than they need to be in winter. Assuming you no longer use open fires, those vents can be bricked up and plastered over on the inside. That is especially true if extra care is taken to minimise sources of moisture generation, such as in kitchens, bathrooms and clothes drying and localised fan extraction.

We had four such through the wall vents, which I did away with in the 1980's.

 

[JohnD]

probably convection currents. If air is coming in through the vent it must be going out somewhere.

Do you have holes in the ceiling, for example for downlighters?

In hot sunny weather, the air in a sunny room can get hot, and a loft extremely hot, and air from the house will tend to rise into it and escape through the eaves. open the loft hatch and you will get terrific airflow on a sunny day. There is a chance your neighbours builders have made an opening enabling more airflow.

If you can't find the path of the air current, use the smoke from a joss stick.

 

[JohnD]

btw I used to have a 1930's house.

All the rooms (except kitchen, bathroom, and small bedroom) had fireplaces

The rooms with no fireplace had an airbrick.

I speculate this was to encourage ventilation. In a room with an open fireplace, air escapes up the chimney.

BTW your bricked-up fireplaces ought to have an airbrick to ventilate the flue, or they will become damp due to internal condensation.

 

[John walter]

Thanks for your input everyone
Suddenly stopped this morning and has since started again
I do have a electric vent at top of stairs ceiling which sucks air from house into loft and out
I am going to switch this back on see if any difference
Not sure