Pointing advice - Joint depth for sand & cement

[mattg]

I’ve finally finished laying my 80sq meter patio & am just about to start pointing it up. Originally I had planned to use sweep in Easypoint but that’s costing up at over £400 so I’ll be using traditional sand & cement instead. I want black/dark grey pointing (the paving is Marshall’s grey sandstone) & had intended to follow Tony’s testimonial https://www.pavingexpert.com/point04 but a builder friend suggested using roofers Remix black bedding mortar to negate the faff of getting every gauge the same so I have 12 bags of that ready to go (at a much more reasonable cost of £90)
I plan to knock it up semi dry & then follow Tony’s guide but am concerned my joints now aren’t deep enough as I’d only left them 20mm ready for the sweep in gear, Will that be deep enough for a semi dry mortar ??
Cheers, Matt.

[dig dug dan]

That's fine a depth, what width have you got?

[mattg]

Thank's Dan,
I was aiming for 15mm which most are but others anywhere between 10mm & 20mm.

[Tony McC]

The depth is OK and the width is....errr....let's call it "generous"!

The idea with paving is to see the flags rather than the jointing, so we try to keep joint width to around 10mm

[mattg]

In my defence Tony the layout you did for me said “9-15mm wide Class II tooled mortar joint or suitable resin mortar�. I had 5 different sizes of flag in the layout & within those sizes a further variation of up to 5mm per flag...
Myself definitely NOT being a paving expert I went with the upper figure to give me more margin for error & I think all things considered over 80sq meters I did pretty well to keep the widest joint to only 20mm!! :laugh:

[Tony McC]

9-15mm is the standard spec for flagstone joint width, but we aim for 10mm.

With random layouts, there has to be an element of joint balancing which always results in some joints that will be a little under 9mm or a little over 15mm, but we do try to keep these to a minimum.