Refixing loose patio slab

Soldato
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Yes those mixtures are correct but dont add any water at all. With patios, the idea is that the compressed sand will create a unmovable based which give your patio is already down, it will be.
The pointing sand is there to stop it moving about by packing it, eventually the moisture of rain or in the air will bind the 50/50 mix together, if you really want to you can sprinkle it with a watering can but I never do, as it weakens the sand and you have to keep packing more and more in as it leaches down and makes a right mess.
It also means that you can sweep away the excess without it sticking to your slabs. As it will leave nasty concrete marks if you don't clean it off adequately.
 
Soldato
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Slabs should be laid on a full mortar bed really but to rebed just one use Sharp sand not builders sand. 6:1 ratio is most common. Building sand should only be used for the jointing, not the base.
 
Soldato
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Well I got a gorilla tub, 40kg coarse sharp sand, 25kg cement, trowel and gloves for under £20 from builders depot. **** me though, I need to go weight training, those bags are heavy, particularly the sand!

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So the problem now is, how do I move and store the sand bag once opened? It'll need to come through my flat to my garden shed but I can see it pouring out everywhere. Maybe I should put it in the shed before opening and then take what I need from there. Does cement ever go off if kept dry?

Ok sorted, moved to shed. I've kept the sandbag off the floor in case insects want to bite through it.

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Soldato
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I wouldn't add water. We have a patio laid on a motar mix and two of the slabs are wobbly. In contrast, the front driveway had a few slabs laid on a dry base of sand and they haven't moved one bit.....and that's with cars driving over them everyday.
 
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All done and yes, no water added. Took a few relifts of the slab to remove excess sand and cement and smooth it down before the slab was sitting flush. Then I used the excess to fill the pointing gaps. Hopefully it shouldn't wobble anymore. I'll mix some sand and cement with water tomorrow to fill in the hole in the wall.

 
Soldato
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Cheers sadat. I just bought a couple more tools. Needed a chisel for breaking grouting as I'm thinking of redoing the pointing on a wall. This chisel is really nice and weighty, only £2.85. And I bought a plastering trowel but for the purpose of using it as a float.
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Soldato
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I filled two holes and it's gone off and feels pretty solid. Very dark colour though. I used an odd ratio, 5:2. Should I have used a different ratio to make it lighter coloured? Whoever repaired the section above mine got a grey colour and smoother finish. I'm quite happy to smash it out and start again. I think I should have added more water, it was a bit dry and clumpy.


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Associate
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At 2.85 that's is really good value. I'm not sure about the mixture but you can always sand it down to get as smooth as you want to depending on how high grit you want to go up to.
 
Soldato
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At 2.85 that's is really good value. I'm not sure about the mixture but you can always sand it down to get as smooth as you want to depending on how high grit you want to go up to.

Yes, that chisel seems to be very good value. I wish I didn't have a massive bag of coarse sharp sand and had bought soft builders sand instead. Apparently coarse will always have a gritty finish and builders sand would be smoother and lighter coloured, better for pointing I think.
 
Soldato
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Yeah wrong sand, building sand is the one for pointing. However matching mortar colours exactly isn't easy anyway.

I'd buy a bag of building sand from builders depot as it will no doubt be good quality but they don't do smaller than 40kg and I'm running out of shed space. Wickes and B&Q do smaller bags of builders sand from a company called Tarmac, but according to reviews on the B&Q page, it's not good, full of stones and grit apparently.
 
Soldato
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I use tarmac sand all the time and never had an issue, however you can buy mortar prmixed in tubs as well for small jobs. It is a little more pricey but no bags of sand laying around.
 
Soldato
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I use tarmac sand all the time and never had an issue, however you can buy mortar prmixed in tubs as well for small jobs. It is a little more pricey but no bags of sand laying around.

Ah that's good to know Tarmac is ok. What is the amount in those bags, is it about 20kg?
The premixed mortar is a good suggestion too.

could you not sand down when dried? You still retain the problem of the colour tho.

Actually I sanded it with 80 grit today. Looking a lot lighter coloured now.

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Associate
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Looking good there I'd say!

Yeah would could start lower maybe 60 then 80 and then go up to 180 if you want a really smooth finish. Finally you could paint it over to match the rest of the walls /brick colour(spray paint and you can use cardboard to cover up unwanted areas). Should be an easier method I think.
 
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