I've just had a double garage built with a roof terrace on top. It has a bitumen felt layer below the flagstones in the photo below. At the sides, the lead flashing is bonded between 2 layers of felt.
The problem is that there is now a fairly large amount of white staining on the outside garage brickwork underneath the flashing...and quite heavy crusty white deposits on the lead itself. It is much worse than in the photo below...although you can see a little of the brickwork staining on the far right.
So is this lime coming out of the cement used to set the flagstones, or maybe from the mortar between the flagstones? Is it reacting with the lead?
Will it eventually stop on its own accord, once the lime is all washed out? (roof has now been complete for about 2 months). And is there anyway to clean this stain off? I've tried a 120bar pressure washed and it does removed it from the bricks albeit very slowly but it cant seem to clean it off the flagstones.
Thanks!
The problem is that there is now a fairly large amount of white staining on the outside garage brickwork underneath the flashing...and quite heavy crusty white deposits on the lead itself. It is much worse than in the photo below...although you can see a little of the brickwork staining on the far right.
So is this lime coming out of the cement used to set the flagstones, or maybe from the mortar between the flagstones? Is it reacting with the lead?
Will it eventually stop on its own accord, once the lime is all washed out? (roof has now been complete for about 2 months). And is there anyway to clean this stain off? I've tried a 120bar pressure washed and it does removed it from the bricks albeit very slowly but it cant seem to clean it off the flagstones.
Thanks!
