Joined: July 2004
||Posted: 01 Aug. 2019,11:33
The "self-setting sand jointing compound" you mention is, I suspect, a particular brand that has a reputation for not living up to the claims it makes for itself, particularly in regard to weed control.
Like most polymerics and 1-parts, these products never really form a good, effective bond to the paving itself, so you get movement and shrinkage cracks.
While loose gravel or splitt would be a suitable joint fill, it would NOT provide weed control, nor is it suitable for pavements subjected to regular power washing. It's not really a technique we recommend for any 'normal' patio project - instead, we keep it back for cottage-style paving where a degree of failure and disorder is required as part of the so-called "charm".
So: you have the usual choices - a good quality 1-part, a costly but effective 2-part, or a sand/cement mortar of some form. When you are uncertain about the build-up, and the bedding in particular, sand/cement mortars are a gamble, as they *must* have a firm substrate. Good quality 1-parts can cope with minor movement, as can the 2-parts, but it seems foolish to spend good money on a jointing medium when you don't know what lies beneath. Like spending top dollar on a lovely car re-spray without treating the rust first.
The flags in the photies aren't particularly good, so, in your position, I would have to weigh-up whether it was actually worth spending any money on trying to turn them into something vaguely decent that might tide me over for a couple of years, or whether it would be a better strategy to rip the lot out and have quality paving laid in its place, and know that the job is done for at least 10 years.
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