Hi all
Terrible site....NO! kidding:D
During the summer I laid 900 x 600 flags, approx 20 of them. I used semi-dry mortar for jointing. We had a long spell of really dry weather so all was well. The problem I have is that our garden has quite a lot of moss throughout, in various places and the slabs are now also starting to turn a kind of green colour, and the joints have attracted a lot of moss and small weed. I feel I might need to re-joint. I don't mind this at all, but I would like to know what I can use to prevent this happening after such a short space of time.
I hope this isn't a gardening problem, cause I don't think there's such a good site as this anywhere. Cheers guys and gals.
The "green stuff" is algae. You can get rid of it by swilling down the flags with a 1:1 dilution of cheap household bleach with a stiff brush.
As for the jointing - semi-dry brushing-in never gives a hard joint. It remains soft, crumbly and porous, thereby making it the ideal home for vegetation. Replace with proper mortar.
How to keep the algae away in future? Swill down with diluted bleach once every 4-6 weeks or so.
