Damp patch on EXTERIOR cavity wall

[trickymicky69]

Hi,

I have a damp patch that appears during/after rain.

The patch seems to "grow"

Gutters and downpipes are clear and drains are free running.

There is no moisture evident on interior wall

Roof doesn't seem to be leaking either

 

[trickymicky69]

Pictures.....

Untitled

• trickymicky69
• 17 Nov 2014
• 1

Untitled

• trickymicky69
• 17 Nov 2014
• 1

 

[freddiemercurystwin]

 

[trickymicky69]

Thanks, just figured it out.

Any ideas what the patch is?

 

[ree]

Probably the throating on the stone sills is absent or damaged. Feel and look under the sills for a continuous throating groove.

It looks as tho someone has pulled and replaced a corner brick - possibly to have a look inside the cavity? But if no signs of damp inside the bay then the cavity is doing its job.

One other thing that you might look at is for any drips splashing down from the bay roof edge or guttering?

 

[trickymicky69]

It was me that removed the brick (I turned it round as the other face had spalled)

What does a throating groove look like?

Thanks

Mike

 

[trickymicky69]

Also its not under a bay window, its on the corner if that helps

 

[ree]

I apologise for guessing wrong. And to guess again, is that white painted Tyrolean render above the brickwork?

 

[trickymicky69]

Its white painted render (pebbledash) I don't know I its tyrolean though?

 

[trickymicky69]

Sorry forgot to say, to the touch the patch feels dry?

 

[ree]

The render should have a bell cast at the very bottom - the bell cast acts to throw off the water thats run down the render. If you dont have one maybe the water is trickling on to the brickwork below.

If you have water stains and no damp effect i have no idea what that could be.

 

[trickymicky69]

I have just noticed in this area (under where the render stops) there is a virgin media cable running horizontally.

Could this be causing a bridge from the render to the cable to the brickwork
Iyswim?

It was installed end of August and that's the first prolonged period of rain we have had

 

[Alastairreid]

Watch and see where the water is tracking next time it rains.

 

[trickymicky69]

It now hasn't rained for two days and the patch is getting bigger

Maybe bath waste pipe leaking into cavity?

Seems strange as hasn't been disturbed

 

[jeds]

Id say it's more likely to be felt drips leaking into the top of the wall at roof level. Corners are notorious weak spots due to felt edges deteriorating or where the cloaking boards end at the bottom of the gable. Water dripping down the cavity could be spreading sideways lower down due to an obstruction or snots. Check the felt drips and cloaking boards.