In article ,
says...
In article ,
"keith_765" writes:

"Andrew Gabriel" wrote in message
. ..
Didn't get to the flaunching today -- that will be tomorrow, or
Wednesday if I need to buy more tiles.

I would like the tiles to overhang the flaunching slightly, so
that even if the tile to flaunching bond breaks, the water still
goes into the gulley. However, that makes it really hard to get
a good finish under the tile edge. The way it was done was the
flaunching was brought up in front of the cut tile edges and
made level with the tile top. This may be because, having removed
the flaunching, I can see the cut tile edges are not in a very
straight line, which the flaunching was making up for.

Still thinking this one through...

Pointing to a tiled valley can course more trouble. Before I comment I
would like to know, which type of tile is on the roof, concrete single lap
interlocking or plain tiles, and is the valley lined with Lead, GRP or
concrete valley trough. By the way 4 to 1 is useless for this type of work.
2 to 1 stiff mix and PVA if you are leaving the old mortar in. BS 5553
states " Open cut lead valley's with plain tiles should not be bedded or
pointed"

I called up Lafarge's helpline, and the chap there was very helpful.
He said to use 3:1, and sharp sand for best result. I asked about
PVA (which I do normally add when I want a strong mortar) and he
wasn't happy about that in mortar exposed to such moisture. He said
if I really wanted a bonding agent, use SBR

styrene butadiene rubber