Patio Mortar Mix

Berger · 24 Apr 2023 at 20:39

Any recommendations?

It’s just 600x600x50mm “utility” slabs - heavy as ****.

I had one which rocked and I used “slab layer” but it’s expensive for what it is and I didn’t like the instructions. Put down as powder lay slab and sprinkle or sprinkle then lay slab.

I ignored them and made a mix up to the desired consistency laid the slab and then had to take up once to get it level (fixing one which rocked).

This time I’m adding 6 paving slabs to the side so was just going to mix sharp sand & cement as it will be a lot cheaper (half the price), give me more working time and a more conventional material to work with. £4 a bag of sand (5 bags) and £6-8 for cement one bag, vs 6x £8 a bag. Anything else to add to it? I’ve seen 3:1, 6:1 and 8:1 ratios!

The internet is all over the place with mix ratios, will be foot traffic, at most a car on the very first slab only. I’m laying over 100mm concrete sub-base, I’d estimate 1” thick mortar to cover the full base of the slabs (not dot & dab).

G_Wizz · 24 Apr 2023 at 21:14

The mix isn't really that important unless you are building a wall, 5 or 6 to one woould be fine.

j.col · 24 Apr 2023 at 22:10

G_Wizz said:
The mix isn't really that important unless you are building a wall, 5 or 6 to one woould be fine.

This^^^^^
Also if you have a couple of straight poles or even broom handles, you can set these at the right level into the mortar mix and screed the mortar (fairly wet, just a little dryer than brickies mortar) to a smooth finish and then lay the slabs on the mortar, (remove poles first lol)

A2BDriver · 24 Apr 2023 at 23:38

Dont forget to prime your slabs before laying them down. Some SBR and cement.

drakulton · 24 Apr 2023 at 23:59

Is this some kind of outdoor artillery soundtrack?

Lean · 25 Apr 2023 at 06:43

We used to lay these "council" slabs on just a screed of sharp sand. The 70mm 3x2 monsters. Horrible. You made sure you got your bed correct because no one wanted to lift and relay any of these.

Berger · 25 Apr 2023 at 09:01

Lean said:
We used to lay these "council" slabs on just a screed of sharp sand. The 70mm 3x2 monsters. Horrible. You made sure you got your bed correct because no one wanted to lift and relay any of these.

I think last time I had some of that plastic strapping they use on pallets to hold things down: slide it underneath and wrap up the side then if needed can adjust if not slip it back out. Only really needed on the last slab.

JRJ · 25 Apr 2023 at 19:21

Slurry mix on the back, either premade or SBR and cement as someone mentioned.

Armageus · 25 Apr 2023 at 19:45

3 sharp sand & 2 builders sand to 1 cement

The builders sand makes it a bit easier to work with and grips better, whilst retaining some of the extra strength of the sharp sand

bigmike20vt · 26 Apr 2023 at 06:58

Lean said:
We used to lay these "council" slabs on just a screed of sharp sand. The 70mm 3x2 monsters. Horrible. You made sure you got your bed correct because no one wanted to lift and relay any of these.

as a kid I remember laying 3x2s with my dad. brutal work and it did his back in eventually and was never right since....... he ended up refusing jobs where customers insisted on them and would only use 2x2

The_Arbiter · 26 Apr 2023 at 07:24

I've got a load of those at home council slabs at home. I can't imagine any oldschool labourers are in good condition now.

SpellowHouse · 26 Apr 2023 at 07:34

Berger said:
Any recommendations?

It’s just 600x600x50mm “utility” slabs - heavy as ****.

I had one which rocked and I used “slab layer” but it’s expensive for what it is and I didn’t like the instructions. Put down as powder lay slab and sprinkle or sprinkle then lay slab.

I ignored them and made a mix up to the desired consistency laid the slab and then had to take up once to get it level (fixing one which rocked).

This time I’m adding 6 paving slabs to the side so was just going to mix sharp sand & cement as it will be a lot cheaper (half the price), give me more working time and a more conventional material to work with. £4 a bag of sand (5 bags) and £6-8 for cement one bag, vs 6x £8 a bag. Anything else to add to it? I’ve seen 3:1, 6:1 and 8:1 ratios!

The internet is all over the place with mix ratios, will be foot traffic, at most a car on the very first slab only. I’m laying over 100mm concrete sub-base, I’d estimate 1” thick mortar to cover the full base of the slabs (not dot & dab).

The ratio is not too important, but what is important is how quickly you want to place a load on it. Also, how well it is mixed. If you want to use it quickly, then 3:1.

Lean · 26 Apr 2023 at 10:11

Lads I'm smiling at your recollections. I sit with my father, 87 telling war stories of the construction industry. He calls me soft then tells me of the nightmares working in the steel industry 1960-1992. He had it harder.

Berger · 26 Apr 2023 at 15:43

Lean said:
Lads I'm smiling at your recollections. I sit with my father, 87 telling war stories of the construction industry. He calls me soft then tells me of the nightmares working in the steel industry 1960-1992. He had it harder.

Okay.

Anyway.

Excavated out and formed up adjacent to the paving, removed the old kerbs which I thought were just pavers cut in two, but they are actually proper edging kerbs. I don’t want to reuse them I was going to use a black brick instead I think.

Old paving looks to be 75mm unbound type 1 material looking at the profile. However I know the old drive used to be sets so I don’t want to guarantee they didn’t just lay straight ontop of those and they are just hidden…. I don’t think so but can’t guarantee it.

As I’ve no van and it’s only a small area, I’m not doing it in stone as I don’t have a compactor and the cost of hiring one for such a small area is prohibitive. I have an SDS+ drill but they don’t make plates for it and I’m not doing it all by hand tamp.

My neighbours having concrete delivered next week hopefully for a shed slab and I’m having his left over - I need approx 0.2m3.

I’ve dug down past the old base and I’m onto subgrade which for me is firm clay / aside from one spot by the front wall where I took a bush out but have gone deeper here chasing out the soft material.

It’s going to be totally overkill for foot traffic, but never mind!

The pavers used are 600x600x45 not 50, I was measuring the kerbs assuming they were the same: I can’t seem to find 45mm thick. I’ll probably use 38mm - Wickes have Marshall’s for £11 ea, as long as the pattern matches. The weight saving will be appreciated & I don’t need to worry about the strength of them so much!

I Just have to carefully lift the old half pavers where they have been cut to fit the kerb as I’m not doing a straight line of new pavers next to the old paving as it would look daft. They are very tight with no mortar/joint so fingers crossed the replacements slide in easily!

Lean · 27 Apr 2023 at 06:18

Why quote me? Actually nevermind. Crack on son.

Berger · 30 Apr 2023 at 12:49

Will do.

Had a look at the Marshalls slabs the natural is perhaps a little more grey than mine, but they didn’t have buff at the builders merchant to be certain. Wickes do but they are thinner, I’ll take my offcut in and have a look side by side.

I think the thickness must be quoted including dimples as I measured them to be 45 (side by side) not 50mm.

My formwork is currently filling up and becoming a moat, should drain away tomorrow or the concrete will push it out anyway!

Berger · 29 May 2023 at 17:58

Nobody likes an unfinished project!

Here is a before/during/after.

I added one slab width to the drive and took up the old half slabs to make it match so 600 plus a single brick edging.

Dug out 100mm topsoil onto firm clay, formed up and had a concrete base, threw the old kerbs in to bulk up you can see these ghosting as it dries. I know not best practice but there is no chance of this breaking given it’s only foot traffic!

I did use slab mix as I was worried about mixing my own but in hindsight should have just mixed my own mortar.

The slabs I borrowed from behind my shed as I think they match the others (when jetwashed) any off the shelf ones were too grey.

For the edging it’s edged/haunched with concrete, some premix concrete but mostly mixed myself using ballast/cement as much more cost effective. Bought in smaller amounts as I kept getting low value B&Q discounts with the app and I could shuttle back and forth in the car then.

Doing it again I’d mix my own mortar instead of using slab layer and make a drier mix for the brick edging, they aren’t as good (slightly rotated a few) as I could have got them, the ballast had a lot of water in it so I ended up with a higher slump concrete than planned and ended up chasing my tail adding more ballast/cement until I had about 60kg and a full bucket mixed up so had to go with it.

Overall I’m pretty happy, it looks on a par with 90% of the drives I see and cost me £100. It was too narrow before and always ended up standing on the gravel or tripping over the sharp kerbs.

drakulton · 29 May 2023 at 18:29

I have the 12" orange vinyl version of this.