Damp kitchen ceiling (near air brick) after heavy rain

[Mikey2]

A line of damp appeared yesterday on the kitchen ceiling from the wall extending into the middle of the room. Looks like three puddles above, soaking through and linking up. The house is just over two years old (George Wimpey).

My only idea is that there is an air brick outside at ceiling level and we had absolute torrents of rain all day yesterday. The air brick is pretty well adjacent to where the dampness starts at the wall. The dampness has more or less dried out overnight (once the rain stopped).

Is there anything obvious I can do to check whether the air brick is the cause, or what else it is likely to be. And if so what would be the best cause of action to fix it?

Incidentally, I'm not clear why there would be an air brick at ceiling level. It is also adjacent to the cooker, which has an extractor fan but which, as far as I can tell, does not have an vent through the wall from the inside.


thanks for any help/advice you can give

Mikey2

 

[JerryM]

The vent and rain does sound the likely cause but cavities (in cavity walls) were introduced to stop this from happening. Normally damp puddle marks on ceiling’s = plumbing.

Start by borrowing a neighbour’s ladder and having a look into the vent to see what it’s doing. The only vent I would expect is for a kitchen extract. This should have a plastic/stainless flexible tube which spans across the cavity. The inner leaf of brick should be sealed around the flexible to stop water ingress. The vent may be just to ventilate the cavity in which case the inner leaf of brick should have no holes in it and the problem lies elsewhere. It’s possible that the vent is for the upstairs floor in which case the cavity should be “closed” around the vent (you can not see into the cavity wall through the vent). This could cause the problem in extreme weather. In this case I would look to change the type of vent to make it more difficult for water to penetrate.

If the vent does not seem to be the problem then there’s no real alternative but to take up the carpets and the floor boarding to have a look at what’s happening. I would wait and see if the water/dampness reappears (given it's not occurred in last 2 years). Could have been a very infrequent fluke of whether conditions.

You will need to repair the stain with several coats of gloss or a proprietary stain blocker.