a few weeks ago I wrote in to discuss moss in the joints between slabs, 900-600. I originally jointed with Kiln dried sand. Removed after a while and jointed with 'dry mortar' mixture. The problem has returned, with both methods of jointing. I.E. Moss and weeds quickly establishing in the joints. I think I should use'Catch-up' pointing to have a solid hard joint. My wife liked the colour of the Kiln dried sand, so I thought maybe we could colour the joint with an exterior masonry paint. Don't know really , what do you guys think.....cheers for the help if you can .
i would use a sand, cement and buff coloured dye, if you use a dry mix for pointing, if you dont pack it down its very loose and easily breached by weeds etc, moss will occur on pretty much everything, just keep giving it a good brush every so often. With the dye you dont need to paint, i dont have any knowledge on the jointing/sealing products other than sand and cement, the others on the forum may have a better solution to this problem
Thanks Stuarty for the reply. I did pack down the dry sand/cement mix quite solid, damn weeds they just dig in there, that is why I thought I would now use mortar in the joints, although this is very late after the slabs were laid. Just one of those things. I don't know if its possible to get mortar very light as is the colour of the Kiln dried sand?. Ah well, I will appreciate any advice or opinions.
Cheers again. :;):
If you get a silver sand, it's easy to make a light-coloured mortar. However, if you start with the red building sand used in Northern England, the orange stuff used in the Sarff-eeest of Ing-er-land, or the dark whin sand used in Scotland, it's impossible to lighten the colour.
If your missus like the KD sand, you could try making a 5:1 mix of it with cement to see how the colour develops. It might be worth considering the use of a white cement (commonly sold as Sno-Cem or some other such ridiculous name) to help keep the mortar at the paler end of the spectrum.
Why not consider a brand new product called Romex 'Terrace Patio'. This is a liquid that you mix with kiln dried sand. You need minimum 5mm gap
Tony - dont know if you have seen this one yet??
The liquid doesn't change the colour of the kiln dried thus therefore keeping the Mrs happy. You need one tin per 25 kg of kiln dried sand and mix together in a mixer for 5 minutes. You then pour the product onto the paving and brush into the joints - really easy with no staining. 25kg of sand will probably cover 6-8 m2 maybe more. I'll see if i can send you a pic of our display.
As for weathering - i don't know yet, supposedly better than previous other products on the market. My guess is that it will prevent weeds but moss in joints with this kind of product will always be an issue especially in our climate. The product takes up to 7.5 tonne load - thus pressure washing off once or twice a year may be the answer with the product staying in the joint. Let me know if you need some more info - the product is due in to us in 2 - 3 weeks!!
Why not use an old product called "lime". Its very cheap, and mixed with sand gives a much lighter mortar, takes longer to set so is much easier to work with, and the alkalinity tends to keep the weeds down as well.
...I've not seen the new Romex product at first hand because the distributor bullshits me every time he opens his mouth. I sense he's avoiding me because he knows I'm going to bawl him out for wasting my time and making arrangements he had no bloody intention of keeping when I was in Ireland last month.
Adding to Danensis' point about lime, I should have mentioned that in my previous post, so thanks for reminding me, Jon.
Here's a pic of some lovely Liscannor slate with a Kilkenny blue limestone gully surround, all pointed using a lime mortar. This is a job I helped out with in Co. Limerick last summer. The lime mortar has easily withstood the worst that a wet Irish winter could throw at it, and although it has gone slightly green, it comes clean when brushed with a weak dilution of household bleach....
Just passing through this thread but having just got old london slabs in grey/green and yet to lay and point them I'm pleased to note that lime morter whethers to a green/grey finish.
Not sure if this helps you but as to other colours I used a black dust additive to morter recently to obtain the drag grey colour of pointing found in our stonework. It was like school paint powder and you simply add a bit until it is the colour density required. It's called sealocrete by Sealotone. They do buff abd yellow and you can adjust the mix as I have. See the product display at http://www.sealocrete.com/product/36/0
danensis wrote:Why not use an old product called "lime". Its very cheap, and mixed with sand gives a much lighter mortar, takes longer to set so is much easier to work with, and the alkalinity tends to keep the weeds down as well.
Just got back to the website, and I see danensis input is very appealing.
I was wondering though, what kind of sand would be best used considering kiln dried sand light colour that we require.
[/quote]and mixed with sand gives a much lighter mortar
a few weeks ago I wrote in to discuss moss in the joints between slabs, 900-600. I originally jointed with Kiln dried sand. Removed after a while and jointed with 'dry mortar' mixture. The problem has returned, with both methods of jointing. I.E. Moss and weeds quickly establishing in the joints. I think I should use'Catch-up' pointing to have a solid hard joint. My wife liked the colour of the Kiln dried sand, so I thought maybe we could colour the joint with an exterior masonry paint. Don't know really , what do you guys think.....cheers for the help if you can . 
