What's the best way to apply mortar between paving flagstones?

[brianroberts]

I'm looking for the best way to apply mortar between exterior paving flagstones. I have used both dry and wet mixes in the past. The dry mix is easy to apply - just brush in - but after a year or two the results are not very good. The mixture gets crumbly and never fully sets. The wet mix approach gives a better long term result but is hard work to put on. Is there an answer to the dry mix approach so that it sets properly and gives long lasting results. Maybe some extra additive to the mix? Any suggestions gratefully appreciated.
Thanks.

 

[theprinceofdarkness]

Depending on the gap. I fill the gaps with peas shingle to within 1/4" of the finished surface. I use a wet mix with a 6mm striking tool, cutting of "sausages" of mortar from the surface of a brickies trowel. You could just use a piece of flat sheet metal laying on a piece of board (to keep drips off the paving surface).
The problem with a dry mix is that its not fully compacted, its full of microscopic air holes which water gets into then freezes and turn the mortar into dust.
Frank

 

[^woody^]

Dry mix, fine render sand, not building or screed sand, compact in the joint then fine mist spray with water to dampen the whole joint not just the surface.

Or a pointing gun. There is no better than the Point master.

Or use an effective, but expensive, geo-set dry brush product.

 

[mikeey84]

I used the wickes own brand geo set brush in product and it was dead easy, but I only did it a few weeks ago so can't tell you how well it will last!

 

[noseall]

Any brush-in muck, quite frankly is absolute s**t.

There is no substitute for solid bedded slabs, bedded on screed sand mortar with all joints formed from the bedding mortar, filled, then struck when firm. Jointing mortar is then solidly connected to the bedding mortar and sets like bell metal.

Anyone that points slabs after they have been laid is not a pro', does not know how mortar works and watches far too many home make-over programs.

If you must point retrospectively, use a sharp sand mortar with a smidgen of building sand to make it workable. Damp the joints down and allow to dry but not completely. Just get rid of the ponding water. Point the joints, let the muck stiffen then hit it with a jointing iron.

 

[stuart45]

Any brush-in muck, quite frankly is absolute s**t.

There is no substitute for solid bedded slabs, bedded on screed sand mortar with all joints formed from the bedding mortar, filled, then struck when firm. Jointing mortar is then solidly connected to the bedding mortar and sets like bell metal.

This is the best way to do it. Patios I've done like this have lasted for years, even when pressure washed. Brush in often comes out with the first wash.