Internal walls at exposed corners of semi damp/wet

[Zuzanna2801]

Recently moved into a 1940's semi and have damp patches on internal walls. Both rooms are at opposite exposed corners of the house and have an old maisonary vent in place, though the vent in the front room has been blocked from the inside with plaster board. Should the vents be blocked? Is it possible to have penetrating damp with a cavity wall? The rooms below are fine.
There is also an open vent in the kitchen, no where near a boiler, and yet I have been told that I cannot block this, why? any suggetions would be appreciated.

 

[Softus]

There is also an open vent in the kitchen, no where near a boiler, and yet I have been told that I cannot block this, why?

Who told you that it couldn't be blocked? What type of boiler do you have?

 

[Zuzanna2801]

Hi Softus
Thanks for your reply. The person that told me that I was unable to block the vent in the pantry (kitchen) was a guy from B&Q. The type of boiler is one of the old Potterton's, but this is placed at the other end of the kitchen to the vent that I want to block. Can you advise?
Regards
Zuzanna

 

[Softus]

I can happily advise you within my legal ability, which is to say you need to ascertain whether or not your incoming vent is sufficient for your boiler.

I'm a little concerned about this advice:

The person that told me that I was unable to block the vent in the pantry (kitchen) was a guy from B&Q. The type of boiler is one of the old Potterton's, but this is placed at the other end of the kitchen to the vent that I want to block.

An increase in distance from vent to boiler doesn't lessen the importance of the vent.

There are RGIs on this forum who will advise you, but they'll need to know the exact model of your boiler to determine the type of flue and the consumption of oxygen.