Damp on one side of upstairs bay window

[Gears]

Hi all, hoping for some help with damp on one side of our upstairs bay window!

We’ve been in the house just over a year and a few months after we noticed the wall getting damp.

I stripped the wallpaper back and went through a process of what it may be which was and fixed them

Downspout leaking near it leaking.
Couple little holes in the mortar just by the side
Resealed the windows

Over summer it seemed to go away but now it’s winter it’s back again.

I have dug into the wall from the inside to see how far in it is damp and discovered this compacted black sand stuff all slightly damp. (What is the black stuff?)

It’s rendered on the outside and only thing I’ve not done it repaint the render on the bay.

 

[noseall]

. (What is the black stuff?)

 

[tell80]

OP, ignore those who are ignorant of the building trade, and rely on Tik Tok for laughs. Small minds etc.

To your question:
Your pic's shows hairline cracking in the render.
The interior will probably need to have all the coverings stripped off the obviously damaged panel below the window board?
Sometimes, all the interior panels need opening up, and insulating and waterproofing?
Why not post pics showing all the interior panels?

Worst case you would need to renew or replace the render.

 

[Gears]

And this was last year when it was really bad

OP, ignore those who are ignorant of the building trade, and rely on Tik Tok for laughs. Small minds etc.

To your question:
Your pic's shows hairline cracking in the render.
The interior will probably need to have all the coverings stripped off the obviously damaged panel below the window board?
Sometimes, all the interior panels need opening up, and insulating and waterproofing?
Why not post pics showing all the interior panels?

Worst case you would need to renew or replace the render.

thanks for the reply.

All the rest of the bay underneath is fine and no signs of damp at all. It’s just that right side. I will note that it does seem to get battered that side by the weather.

If the render feels sound when I inspect it can I repaint with masonry paint to reseal?

 

[tell80]

Remove all the plaster and any infill and skirtings on all interior panels. Then post new pics please.

You dont know what paint is already on the render - painting over might make things worse but you can try FWIW.
However, my thinking is that moisture is well established behind the render (& penetrating to the panels) and all vulnerable paint will eventually get blown off.