Rainwater running down inner side of outside cavity wall Re-generate an old or tired space and give it a fresh breath of life. Click here for answers, information and tips

[Perry525]

This is unfortunately quite common.
The standard of brick laying is not always as good as it should be.
Holes are left between the bricks and mortar.
The rain hits the wall like a bullet and the wind blows it through the wall.
Then the water runs down the inside of the bricks as its intended too.
You need external cladding, avoid render as this always cracks.