Random wet patch halfway up internal wall after storm

stuart45

I'd just repair the mortar under the cill and some of the cross joints. I'd leave the Stormdry for now. When the window is out you won't see down the cavity if it's filled with insulation, but you might see if it's damp, or if there's any voids at the top.

WIAWSNB

SyA, I think your own suggestion of the Soudal (or Fischer or Bostik - no idea how they compare) would tide you over nicely. And if you decide next year that the pointing needs redoing on a larger scale, then this stuff would be raked out with the old mortar with no issues. And if it actually does the trick or sorting the damp, then it'll likely last years.

If your neighb is happy to DIY a repair, then I think he'll thank you for this stuff. Ready-mixed, easy to apply and inject/force into gaps, easy to smooth off and remove excess, and it looks very convincing - I guess you'd want it in beige?

I think I'd hold off on the waterproofing cream for the moment, as it may make the bricks repel mortar, should you decide on repointing next year.

Skint_yet_Again

Thank you so much @WIAWSNB I was thinking grey but now you’ve mentioned beige I’ve looked at the pointing on the photos a bit more closely and it does look a more sandy beige colour. 😁

stuart45

The majority of water that penetrates a wall comes through the joints, especially the cross joints. The theory of a 9 inch solid wall is that a softer, more absorbent brick will soak up the rain evenly over the whole wall so less of it gets into the joints. It rarely gets into the brick more than a couple of inches. With a hard burnt brick like yours, more water runs down the bricks and into any cracks in the joints. It's known as the raincoat/overcoat effect. A heavy overcoat soaks up the rain and keeps you dry. A raincoat with a hole in it sends all the water into the hole and soaks you in one place.

What's normally most effective is to have walls properly pointed with a mortar that is weaker than the bricks themselves. If mortar is too strong, it shrinks more leaving small cracks between the joints and the bricks.

Skint_yet_Again

Thanks @stuart45

How do I know if the mortar is weaker than the bricks?

Boohoo

https://forums.moneysavingexpert.com/discussion/comment/82186711#Comment_82186711

Let them fight it out🤣

Weak mortar would crumble but I am not an expert but others will give a concise explanation soon.

stuart45

https://forums.moneysavingexpert.com/discussion/comment/82186711#Comment_82186711

When you repoint you use a suitable mix. Normally it would be the same mix as the original, but a touch weaker. On some jobs the original mortar is sent away to be tested, but normally you guess what is about right. If it's an old property with soft bricks and lime mortar, you'd use a soft lime mortar. If it's a more modern house with harder bricks it could be a 1/1/6 mix. The bricklayer doing the job normally makes the decision. A lot of so called pro pointers seem to use a 4 and 1 sand/cement mix for everything. Using the wrong mix normally takes quite a few years to do any damage to a wall, so they can usually get away with it.

WIAWSNB

As Stuart mentioned, best not to let your neighb use his bag of 'concrete/cement mix' for this reason. Unless he knows what he's doing.

Even then, I think it's worth considering what the medium/long term plan may be.

Perhaps worth calling out a couple of reputable and recommended builder/plasterers to assess the state of the wall, and what needs doing?

And what do you think - is the existing mortar soft enough to scrape away using, say, a stick?

If the consensus is to 'repoint', then I'd definitely use the ready-mixed product to effect a temporary repair - it should do the job for a few years, and then you can have the whole wall repointed back to 'new'.

If the existing mortar is actually fine, other than the cracked & missing bits, then, um, er, I'd still use the stuff to patch and fill... ☺️

Boohoo

I still think that the OP should remove the wallpaper from where that black mark is to see why it's there and to see where it has come from, from the outside under the window or somewhere else to be certain.

It shouldn't matter that much for the decor as OP said there getting new windows next year.

Beeblebr0x

I've read that the Soudal is easier to handle if the unopened tube is immersed in hot water for ten minutes, otherwise it's hard to force out of the tube.