Dripping inside cavity

[AF83]

Hi all, I’ve got a new build with all sorts of issues but the latest annoyance is a dripping noise when it rains heavily which I believe to be inside the cavity, possibly water dripping down on to the cavity tray as it sounds hollow/plastic.

Possibly coincidentally, the noise, though downstairs, is roughly in line with the “exhaust” of the extractor upstairs. I thought water may be running in from the vent, then dripping down into the cavity so I took the extractor off upstairs and found that after removing the 4” pipe for the extractor, although the inner block work seems dry, the inside of the outer brickwork is completely saturated above and below the hole for the vent.

I know these bricks to be pretty porous as the single skin garage let’s in plenty of water in heavy rain. I’m just unsure if it’s normal to have the inside of the outer skin so wet, particularly that it’s making a dripping sound every 10secs on to the tray. It looks like the foil is peeling away from the insulation too, possibly from being wet. Developer just tells me it’s probably the wall ties dripping onto the trays and that’s it.

Question is I suppose is it ok to be so wet, is it normal to have water dripping onto the trays enough to make a noise and finally is there anything I can do about it?

 

[JohnD]

can you show us some pics? I especially like Cowl vents, which are good for throwing off wind and rain. The brickwork should have a neat, round, close-fitting hole with no broken or jagged bricks or mortar. If you have small hands you may be able to repair from inside.

I suspect your duct is a poor fit in the brickwork and/or was not sealed (I pack mine tightly with mortar, which I think looks best and is durable, but more work than sealant)

I also take the trouble to slope the duct slightly so that any rain or condensation runs to the outside, but I have noticed people often get that wrong.

Water should not be dripping into the cavity.

Sadly, bosses of building firms very seldom get sent to prison.

 

[AF83]

Thanks John, I’ve tried to add a pic from the inside. The duct is definitely a poor fit as it’s just 4” pipe which sits loose. Strangest that it’s wet inside above the hole too. Think that might be saturation of porous bricks though. I agree a cowl vent would have been better, these are louvre type and I don’t think they’ve even put a bead of silicone around them.

 

[JohnD]

that wet is terrible. might be rain blowing in (louvres are not much good)

it could be lodging on the top of the outer grill casing and running inside through a crack or screwhole

If you can get up there, a cowl might be big enough to cover the gap. The cowl has a round moulding that the plastic duct fits.

Though if it was me, I would try to mortar in any gaps and smooth off. like filling a tooth, you need to press the mortar deep into the gap, if it just covers the surface, it will fall out.

In daylight, have a look above in case water is dripping from the roof, eaves or gutter onto the grille.

Your building manager is fobbing you off in the hope that you will give up and stop bothering him.

 

[^woody^]

Inner faces of external skins do get saturated, and ties are designed to allow drips, but there should be no constant drip drip and even so drips should not be audible and cavity bridging from vents or liners should not be creating drips in the first place.

If you are certain that the vent is the cause, what is below that the drip is hitting to make the noise?