Identify this mortar, please!

[RDMotorsport]

I have recently cleaned the paving at the back of my house and although there was some motar breaking up in places, predictably now there is more!

This is how the paving now looks, (apologies for the pictures at 90degrees, they weren't before being uploaded)


Up close,


And a few areas like this, with some gaps not as deep but running almost the width of a stone.


Question being, what is the motar and how close a match can I get these days as id like to get it re-pointed / repaired. Considering the paving was laid 20-23 years ago I believe, its done well but now needs a little refresh.

Thanks,

[RDMotorsport]

Edit, should of course be mortar....!

[Scarletpimpofnel]

That has lasted extremely well imo for 20+ years.

Personally I use a strong 4:1 mix of concreting sand to cement but even then with the hard frosts I get I find bits failing after about 5 years.

I'd be interested to know what mix can last 20+ years.

[Aluminati]

Looks like there’s some sharp in that, which is probably what held it together for so long.

[Drumroll]

Yes looks like it was made up with a concrete sand not a mortar sand. Chances of repointing looking the same almost zero.

[shtu]

I'd suggest chopping all that out and replacing with a modern epoxy mortar, https://www.pavingexpert.com/jointing12

[RDMotorsport]

Interesting, thanks all. Some more thinking required now perhaps!

Yes there looks to be some sharp or another small stone mix in the mortar, its been done really nicely. As suspected, getting a good match is likely near to impossible,

[AlexGSi2000]

I can't help with the type I'm afraid, I'm just posting as my plans this bank holiday weekend are to do the same to the flagging in my garden.

Similar to yourself, mine has been in place 20 years and its full of missing jointing with weeds & grass growing through.

I was going to use a 4:1 mix, but can see there are various products on the market - confused as to what to go for!

[Lotobear]

4:1 with concreting sand and some SBR in the mix

[Drumroll]

Just to be pedantic 4:1 mortar is not a strong mix and whilst it is acceptable for use in brickwork my own feeling is that it is not really durable enough for patio's. My own feeling would be use a patio pointing compound. But clearing out the old one will be fun.

[Lotobear]

Drumroll said:

Just to be pedantic 4:1 mortar is not a strong mix and whilst it is acceptable for use in brickwork my own feeling is that it is not really durable enough for patio's. My own feeling would be use a patio pointing compound. But clearing out the old one will be fun.

It depends really, going too strong can create it's own problems particularly if the flags are flexibly bedded. As a general principle the mortar should not be stronger than the material so 1:4 is a good safe bet and with SBR added it ought to be fine for a range of conditions. The use of concreting sand will also add notional strength to the mix over a sharp/rendering sand and permit a lower water:cement ratio

[shtu]

Drumroll said:

clearing out the old one will be fun

Easiest way is to run a grinder down the centre of the joint with a nice fat stone cutting disc, then pick out the remnants from either side.

Messy but effective.

[AlexGSi2000]

I made a start on mine yesterday.

Purchased a mortar rake for the grinder - absolute godsend, however - its going to take a very......very long time.

Spent 7 hours yesterday raking out a section and re-jointing, I'm about 20% done, so in my estimation its going to take another 25-30 hours.

That said, it looks a damn sight better - no weeds, grass growing through. Hopefully it lasts 5 years, as that's when I plan to change the garden completely.

[wolfracesonic]

Quick suggestion, what I do when removing pointing from paving and it’s quite hard, rather than grind it away, I use a diamond cutting disc to cut a groove down the middle of the joint, then usually the pointing can be removed in long strips with a hammer. I use my 9’’ grinder but it should work with 115 one if that’s all you have.

[ferret50]

Angry grinder, keep BOTH hands on the tool, OP!