Dave Plowman wrote:
In article ,
Chris Vowles wrote:
Both my house and my fathers house have rust lines coming throught
the External Render,

Mine is due to a steel edging bead on my bay window and my fathers is
due to steel bell lip (or what ever they are called) above his
windows (his house is also next to the sea and the salt in the air
obviously doesn't help).

Obviously poor galvanizing. I've had the same thing *inside* the
kitchen, where the rust came through the wall covering. I treated it
with car rustkiller - Jenolite - and covered it with PVC tape. This
seems to have prevented it showing through yet - but outside would
be, I'd guess, a different matter.

Any thoughts on a way to stop the rust coming through,

Only the above. Once rust has started it tends to carry on
regardless, as in old cars, where the only real option is to cut it
out and replace with new metal.

If ever there was a case for a stainless material, this is it, as
render etc should last for many years more than this strip appears to.

I've just seem some rendering done on a new quality property and the visible
steel strips are stainless.