Damp in cellar

[FRAN1870]

I have a small cellar that used to be a coal bunker (normally not accessible as it’s blocked off). It’s about 1.6m deep x 2m x 3m across.

Just been under the floor and the gable wall is ringing wet under the cellar. Render looks fine, isn’t blown and Timbers appear ok but it’s very damp.

The only thing I noticed is that there’s only one air brick?

Surely I need two so that air flows? Just getting air in isn’t enough right?

 

[KenGMac]

FRAN1870, good evening.

With only one air brick in that area there will be dampness.

Is this a "sealed underfloor" area or are the surrounding underfloor walls, dwarf walls constructed in honeycomb construction?? meaning is there any through and through air flow under your home?

If possible can you introduce a couple of air bricks on the 3 m. long wall? but what will assist greatly is two air bricks on each wall ?

At the same time you may want to consider introduction of under floor insulation? the increased air flow will cool down the room above?

Ken

 

[FRAN1870]

Thanks so much for commenting Ken.... the space is around 4ft deep and is an extension to the original house. It used to be a coal bunker so I assume there wasn’t much need for additional air bricks as the door you can see on the right here would of been open and closed frequently.

Two of the walls are blocked off from airflow, one where it joins the house and the other where another extension had been built across the original bunker entrance.

I’ve already insulated the suspended floor... should I add two airbricks or one?
Also should I try and knock through into the main house void too? That only has one airbrick so I assume the same problem exists on that side too?

 

[FRAN1870]

There’s also evidence of woodworm on the joists ‍

 

[KenGMac]

FRAN1870, good evening again.

I would opt for two air bricks on each available elevation.

As for a knock through to the rest of the property? all depends on how many air bricks are fitted now? and is the adjacent underfloor void made up of honeycombed dwarf walls? that then begs the question? what about the overall standard of ventilation under the rest of the house? could be that forming some holes in the wall from the old Coal Cellar would assist generally?

Ken

 

[FRAN1870]

I’m not sure until I get under the kitchen floor .... the kitchen is a gable extension and then the utility an extension to the extension so each is seperate to the main house. The only other suspended floor is under the lounge / dining room and is fine 4 x airbricks front to back with latice in between the rooms

The kitchen only has one external air brick that I can see unless it vents to next door’s void but I won’t know until I go under the floor.

Toying with the idea of having a trap door in the utility and then knocking a crawl space opening through to the kitchen with a small lintel. This will give me air flow as well as inspection access under the kitchen