The Brew Cabin

Posted: **Mon Nov 20, 2006 12:39 pm**

I'm laying an area of 36mm deep concrete slabs (Marshall's faux Yorkstone) onto a light sandy soil inside a brick circle (which is already built and has a decent foundation of MOT and 3 inch thick 4:1 concrete). It is for pedestrian use only.

I wish I had found this site before I started the work.

What I have done so far is excavated inside the circle to depth of slab + 4 inches (after reading this site, I realise deeper than I needed to make it), and I've got a good inch of MOT for a sub base spread out and compacted with a whacker plate inside there. Not much but the soil it's on is so good I guess a sub-base isn't strictly necessary

What I'm wondering is if I do need to make up a 10:1 dry mix for the bed, or can I get away with dry sand (no cement)? I will need around 2 tons of sharp sand to fill the circle up to the requisite level, and it will mean massively more work if I need to mix cement into all of that, by hand (what would be the best way to mix it? I don't have a cement mixer and I've been using my wheelbarrow to mix up the 4:1).

If it is a good idea, could I get away with putting down the first two inches dry, compacted in layers, and only mixing in cement for say the top inch, which would be much more feasible for me?

I'm planning on screeding the bed for laying, but I'm not sure what the best way to do that is inside a circle, the methods in the guide on this site would work well for a rectangular area but not so well I wouldn't think for a circle (4.5 metre diameter with a 'bite' out of it, not quite perfectly round (the fault of the contractors who laid the first half of it for lawn edging). Also made more complicated because the whole thing is being laid on a 1 in 25 slope due to garden geography, so I can't use a spirit level.

What about 'buttering' of the slabs with mortar when I lay them, is that necessary?

Also does anyone know where stocks Romex in the Bedford/Luton/Milton Keynes area? I got a blank look asking about it at Jewson.

Thanks in advance for any help.

Posted: **Mon Nov 20, 2006 5:31 pm**

sternip

do not try and get away with just a sand bed mix the sand and cement properly we like a 7-1 ratio and quite damp. Try and tap the heritage into place it makes for a much better job than screeding when using heritage due to the riven nature of the slab. 2 ton sound like a lot of hand mixing youve just spent hundreds on slabs get down to HSS and hire a mixer

regards

Matthew
drivewaycompany.co.uk

Posted: **Mon Nov 20, 2006 6:03 pm**

Cheers for the reply!

I had an idea though while I was out there today, it occurred to me that the circle is a nicely confined space due to the circle of bricks around it and the hardpacked layer of MOT underneath, almost like a giant wheelbarrow. So I thought, what about mixing in situ, ie putting all or most of the sand down, watering it with a hosepipe, tipping out the bags of cement for the correct mix on to it (spread out obviously rather than one big pile) and attacking it with a shovel for a couple of hours until it's nicely mixed.

I realise it wouldn't be perfect, but I can't see any reason why it wouldn't work, especially with someone giving me a hand so it wouldn't take so long it would start going off. I am young and in very good physical shape so I would be able to go hard at it without getting out of puff after five minutes like a lot of people I've worked with would...

If you can see a flaw I am missing with the idea then feel free to point it out, but I really don't fancy either hiring a mixer if I can avoid it, or mixing 2 tons in wheelbarrow batches for that matter.

If I hadn't already got the sand sitting on my driveway I would probably get extra MOT instead, but that's not really an option now.

Posted: **Mon Nov 20, 2006 6:34 pm**

Dont try and mix in situ, you will just have a seriously inconsistent mix, or end up with the mix full of bits of MOT. Im sure a petrol mixer from HSS is around 30 quid for a week, maybe slightly cheaper.

Also, 2 tons of mix is alot and it really doesnt take long for it to start going off.

The best advice i can give you is to get your mate to mix up the batches as and when needed in the mixer and have them bringing the slabs over to you.

Posted: **Mon Nov 20, 2006 7:19 pm**

Ok, I think I will take your advice about not trying to mix in situ, I still think it could work personally but I don't have the experience of having tried to do it, so perhaps best to stay by tried and tested methods.

But going back to what I said in original post, what is the flaw in putting down and compacting the first 1.5 tons dry, and just making a mix for the last half ton to go on top of that? Surely a lot of people make a layer like that on top of soil, so how is it different to that if it's on top of compacted sand?

Thinking about it I have to say there is no chance of me hiring a mixer, and not because of cost, mostly time issues in that I will have to waste maybe a whole day or more waiting for it to be delivered (I don't have a trailer to pick one up myself) which I definitely cannot afford. For several reasons I need to get this job done quickly without wasting any time.

If the only other way to do it properly is to hand mix the whole two tons in individual barrow loads, I can't afford the time to do that either, so basically I'm looking for the next best way to do it.

Posted: **Tue Nov 21, 2006 12:01 am**

For several reasons I need to get this job done quickly without wasting any time.

imagine how much time you will waste going back and doing it all again if you balls it up
do it right
do it once
you know it makes sense ternip
cheers LLL

Posted: **Wed Nov 22, 2006 1:05 pm**

You are right of course, it is worth taking the time to do it properly, if it takes a lot of time then it has to.

I realise that I had the method of individual bedding with a concrete mix wrong, and so I realise there is not really a shortcut. I have decided to mix by hand in barrowloads, 1.5 inches of the depth below top of slabs after compaction of the layer below. planning on going with an 8:1 mix (I might run out of cement with a 7 to 1).

Thanks for the advice again.

So anyone know where I can get Romex round here? (Bedford/Luton/MK area)

Posted: **Wed Nov 22, 2006 6:12 pm**

ternip aquire a mixer mate look here for a starting idea
handmixing is back breaking and will cost you in the long run
good luck
cheers LLL

Posted: **Thu Nov 23, 2006 1:13 am**

After some consideration I think you're right, it's not a huge job so I really didn't like the idea of getting one in, but I think there's enough mixing to make it worthwhile, particularly since wheelbarrow mixing is such a bastard.

If it's workable outside tomorrow I'll start the job by hand, might be able to borrow one for the next day.

Posted: **Sat Nov 25, 2006 7:54 am**

i used to get the mini digger to knock up for me sometimes when on large housing projects. you have to go flat out before it goes off. if you do it in situ you end up treading it in and it goes off underfoot, barrow mix is stupid. why dont people take this into account when planning. so if you can afford to wait a day to borrow a mixer, surely you can wait a day to hire one. also if money is no prob why skimp on cement.? :p your only going to do it once so do it right mate. lay in haste repent at leisure, as ATS :;):

The Brew Cabin

Bedding questions