Outside cracks and damp?

[blanko]

Hi folks, hoping for some advice here...

During the recent heavy rain, I noticed some water running into the house through the tiles at the back of my woodburner/chimney. The flue itself is bone dry, as is upstairs. It just seems to run through these tiles on the lower level and pool on the floor. Obviously I want to fix it before it gets worse. The house is at least 80 years old.

Outside I noticed the finest cracks in the rendering. I'm wondering if you folks could offer some advice on fixing this problem myself?

Thanks!

 

[Alastairreid]

Does the dash sound hollow when you tap it?

 

[blanko]

Does the dash sound hollow when you tap it?

The vast majority of it, no. But yes, it does sound hollow in one small area, at least. The crack runs down a fair distance of the wall, as you can see...