Help needed on chimney air brick

Liljo104

Hi Hope someone can help me as i’m totally Clueless! I live in a 1920 pit house. The chimney is bricked up as no fire but the hooker hood does sit in the chimney in the kitchen. A while back I noticed that there was a wet damp patch when we had heavy rain. After a quote it turns out the chimney needs rendering and is letting rain in. Unfortunately due to furlough etc that’s not possible at the present time. I know rain can cause mold etc in a chimney which is my other concern. In my sons room in the chimney rest there is a plastic air vent. Not sure if it’s a false wall or not as it’s not solid like the other side of the chimney wall And sounds hollow. The vent sits quite a bit up from the floor so is inline with my sons bed, can’t change the bed around as it’s a small room. Now I’m worried that mold spores could be coming out the vent into his room. Am I best somehow blocking up the vent if possible. I know you should have ventilation but I can’t fix the rendering so I know that’s causing problems in the chimney 

Davesnave

In a typical vented chimney, the air in the house is drawn into the vent and there is little or no no blow back, but air pressure is an unpredictable thing and something like a kitchen fan or a fire using a different chimney can cause the normal air flow to reverse.

Personally, I wouldn't block the chimney vent.  I might start by adding a vented chimney cap (about £50 to buy) and moving the bed.

Liljo104

Davesnave what would a center chimney cap do? Unfortunately moving the bed isn’t a option as the room is so small. Would I be best not using the cooker hood so it can’t push air out? 

Davesnave

Liljo104 said:

Davesnave what would a center chimney cap do? Unfortunately moving the bed isn’t a option as the room is so small. Would I be best not using the cooker hood so it can’t push air out? 

No, you need the cooker hood if it sends air full of moisture from cooking outside. You'll only use it for short periods and you can close thebedroom door if it's really that which is reversing air flow.

A chimney cap, which has ventilation designed-in, will stop heavy rain going down an unused chimney. I stuck one on the unused second chimney on my bungalow although it didn't have a damp problem I was aware of; it's just good practice in high rainfall areas.

Liljo104

I have 3 chimney pots and they all look to be capped off. The rain is getting in as it badly needs rendering. From what I know the cooker hood extracts into the chimney but isn’t vented outside, I’ve now learnt that’s a no no. 

The bedroom is my sons and he’s a teenager so constantly locked in his room lol

FreeBear

Liljo104 said: From what I know the cooker hood extracts into the chimney but isn’t vented outside, I’ve now learnt that’s a no no.

If there is a liner inside the chimney, running an extractor shouldn't cause any problems - It only needs to be a single skin liner, so nothing fancy.

Liljo104

Freebear I have no idea if there is a liner as the extractor was in when I bought the house, is there a way I could check to see? Would it be visible from where the extractor goes up?

FreeBear

You might be able to see past the fan with a strong light shining up there.