Hi,
I've had this problem in one of the pillars, the left side only, next to our patio doors for over 10 years. I try to fix it but it keeps coming back. It also occurs in the same wall in the two flats above use. One I think is caused by condensation from metal windows, we don't have that.
I've applied silicone brick sealer on the outside bricks, checked the door frame, behind which is expanding foam, last weekend cleaned off powder, applied vinegar, then Zinser BIN. Painted over and today it's re-appeared!
It generally only happens when it rains, earlier this year I replaced part of the frame of the window to the left and nothing has appeared there since. It's mostly the right side, where the patio door frame is, and the wall face.
What to do now??
Photos attached.
Thanks.
Geoff
I've had this problem in one of the pillars, the left side only, next to our patio doors for over 10 years. I try to fix it but it keeps coming back. It also occurs in the same wall in the two flats above use. One I think is caused by condensation from metal windows, we don't have that.
I've applied silicone brick sealer on the outside bricks, checked the door frame, behind which is expanding foam, last weekend cleaned off powder, applied vinegar, then Zinser BIN. Painted over and today it's re-appeared!
It generally only happens when it rains, earlier this year I replaced part of the frame of the window to the left and nothing has appeared there since. It's mostly the right side, where the patio door frame is, and the wall face.
What to do now??
Photos attached.
Thanks.
Geoff