Hi
I have been reading about pointing, I recently had my york flagstone patio repointed and am not sure if it is correct. The flags are about 25 - 30mm apart and the pointing has been done such that the mortar is at least 10mm below the surface - is this correct.
On all websites I see that the slabs should be closer but if this is not possible what should you do for pointing.
I think the landscaper has used a dry mix and then wet it in. Will this work when it has not stopped raining since the mix was put in?
Any help much appreciated as I am not too sure if the finished work is correct
York Flags Pointing
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84-1093879891
Generally speaking, when you have an area paved with flags, whether they are concrete or stone, what you want to see is the flags, and not the mortar pointing, or whatever else has been used. If you're paying, say, 80 quid per square metre for paving, then you want as much of the attrractive stuff per square metre as possible, and as little of the cheap, nasty mortar as is feasible.
Hundreds of years of experience with stone (and concrete) flags has shown that, ideally, a mortared joint should be somewhere around 9-15mm wide, with 10-12mm being ideal. This is 'half an inch' in old money. This ensures there is sufficient mortar to create a competent 'block' of material, but not so wide that it looks excessive. Joints wider than that tend to be distracting, drawing the eye away from the stuff that actually costs good money (ie, the flags), and towards the stuff that costs next to nowt (ie, the mortar).
Some flaggers seem to think that big, wide joints are attractive. Maybe they are, to some folk, but not to the majority of people. And some flaggers like to think that big-wide joints are structurally sound, which is total obllocks, because the mortar is the weak point in the pavement. So, the less pointing there is, the better is the finished pavement, both structually and aesthetically.
Using a dry mix with stone flags is a waste. There's absolutely no need for it, and a much better pavement is acheived if a proper wet mortar is used and the flags buttered and pointed as they are laid. With a dry mix, full cement hydration and binding of the sand is rarely acheived. It's an acceptable method of filling an inconsequential gap, but it's a long way short of ideal for jointing stone flags.
Over the medium to long term, it's likely that the jointing will crumble and be colonised by mosses in what seems like no time at all. And because the joints are so wide, comparatively speaking, this then become a hazard, as you end up with 'slip strips' surrounding each flag.
From your comments, it seems that you have had only the repointing done, and that the contractor was not responsible for the laying. If this is the case, then you can't really fault them for the joint width, but, in such a case, a high-strength, resilient mortar, beefed up with a dash of Ronafix or SBR, should have been used, to ensure a hard, weed-resistant joint that won't crumble to dust in a couple of years.
Further, a 10mm rebated joint is silly, It's providing rspace for crud and detritus to accumulate, and for water to lodge after a downpour. A 3mm rebate is just about ok, but 10mm is definitely excessive.
A simple test is to take a screwdriver to the jointing. Hold the tool vertically above the joint and push straight down. Can you push the blade into the jointing? If so, it's bad, and should be replaced.
Hundreds of years of experience with stone (and concrete) flags has shown that, ideally, a mortared joint should be somewhere around 9-15mm wide, with 10-12mm being ideal. This is 'half an inch' in old money. This ensures there is sufficient mortar to create a competent 'block' of material, but not so wide that it looks excessive. Joints wider than that tend to be distracting, drawing the eye away from the stuff that actually costs good money (ie, the flags), and towards the stuff that costs next to nowt (ie, the mortar).
Some flaggers seem to think that big, wide joints are attractive. Maybe they are, to some folk, but not to the majority of people. And some flaggers like to think that big-wide joints are structurally sound, which is total obllocks, because the mortar is the weak point in the pavement. So, the less pointing there is, the better is the finished pavement, both structually and aesthetically.
Using a dry mix with stone flags is a waste. There's absolutely no need for it, and a much better pavement is acheived if a proper wet mortar is used and the flags buttered and pointed as they are laid. With a dry mix, full cement hydration and binding of the sand is rarely acheived. It's an acceptable method of filling an inconsequential gap, but it's a long way short of ideal for jointing stone flags.
Over the medium to long term, it's likely that the jointing will crumble and be colonised by mosses in what seems like no time at all. And because the joints are so wide, comparatively speaking, this then become a hazard, as you end up with 'slip strips' surrounding each flag.
From your comments, it seems that you have had only the repointing done, and that the contractor was not responsible for the laying. If this is the case, then you can't really fault them for the joint width, but, in such a case, a high-strength, resilient mortar, beefed up with a dash of Ronafix or SBR, should have been used, to ensure a hard, weed-resistant joint that won't crumble to dust in a couple of years.
Further, a 10mm rebated joint is silly, It's providing rspace for crud and detritus to accumulate, and for water to lodge after a downpour. A 3mm rebate is just about ok, but 10mm is definitely excessive.
A simple test is to take a screwdriver to the jointing. Hold the tool vertically above the joint and push straight down. Can you push the blade into the jointing? If so, it's bad, and should be replaced.