Tony McC wrote:You can use a Close Joint down to, say, 1 or 2mm, but I'd avoid butt jointing because it is just so much extra work.
Close jointing gives you a little bit to play with so you can accommodate minor size variations in the flags without losing alignment but more importantly, it obviates the risk of spalling resulting from intra-flag pressure on those vulnerable arisses (fancy way of saying "less chipping")
Butt jointing, along with spot bedding and GeoFix, should be condemned to the big pile of crappy ideas we used to have.
hmm............ so close jointing (1 to 2mm) is a viable option.... but runs the risk of water getting between the joint ...freezing and
potentially dislodging the flags,even if a good SBR bond bridge is used.
Cant see the point trying to fill a 1-2mm gap with anything (sand ?) as it wont last 5 minutes with wind rain and pressure washing etc.
It would need to be a very severe frost to dislodge paving in that manner. The sort of overnigh-down-to-minus-4 frost we get in much of Britain and Ireland wouldn;t be capable of breaking the bond.
But don't be tricked into thinking butt-joints are impremeable: they will allow water to enter the system just as easily as close jointing, albeit not quite as much,
And yes; although there are specialist jointing products for close joints, it's hard to justify anything other than KDS
