penetrative damp on exposed wall. Solutions?

[angularbanjo]

Hi, we have a 1970's detached single cavity construction house (block and brick) where there seems to be a problem with a wee bit of damp getting in upstairs via the wall shown in the pictures (see attached) The wall in question is actually part of a slightly later (80's) extension.
The wall is very exposed to wind and rain and faces due west with only open fields beyond (we're in rural Tayside, Scotland) so I'm not surprised there's a bit of (penetrative, is that the correct term?) damp as from October to April we get a fair bit of rain and wind battering in from the west. We've been in the house 25 years and have not done anything by way of maintenance to that wall. (the cavity hasn't been filled btw).
The rendering/harling looks fine, no obvious cracks and the pointing on the brickwork also looks okay (I've attached photos to hopefully show). The filler in the vertical joint (expansion joint?) between the render and the brick looks a bit cracked and my plan is to make that my first job.

So, questions:

Is it okay to just scape out the loose/flakey sealant in the vertical joint and then re-finish on top? What kind of compound would be best for that job?
Should I paint on some weatherproofer onto the brick and rendering to give it some protection? If so, what would people recommend?
I'm new to this, so any other suggestions regarding what I should do would be really welcome

Thanks in advance
Steve

 

[^woody^]

Polysulpide mastic for that joint. With an elastomer or PE Foam backing in the joint if required to fill any gap. That old stuff should be removed.

It's just a joint where the extension is tied, not for expansion.

 

[Ivor Windybottom]

I can't tell from the photo, but what happens where the bottom of the render meets the brick? The brick looks very wet, and it looks like there might be a ledge at the top of it? Probably below the DPC anyway though.

If the sealant doesn't fix it then lots of people rate this stuff, for use on the stone-effect blocks...

Stormdry Masonry Protection Cream

• Waterproofs brick, stone and more• Highly vapour permeable • Single-coat application • 25 year effective lifetime • BBA approved and EST verified• Coverage per litre of 5m²Stormdry® Masonry Protection Cream is a deeply penetrating water-repellent silicone cream for the protection of...

www.toolstation.com

 

[angularbanjo]

Yes, the render sits on a ledge which slightly angles back up into the brickwork, sits about an inch proud. Must just be the photo but the brick is bone dry.

 

[angularbanjo]

Thanks for the replies, neighbour who is a skilled handyman pointed out some gaps just below the tiles on the roof where it meets the wall where rain could be getting in. The damp is most apparent upstairs (still very slight) so the plan is: fill those gaps with sticksall or suchlike, remove the mastic from the joint and refill, then paint the stormdry onto the bricks/blocks and render.