Laying slabs, do I need a cement mixer or not?

Tucker

bobhawke wrote: »

Blob of mortar in each corner is about the worst thing you could do for laying slabs, it leaves them really weak where there is no mortar, leaves gaps for rodents to get in to and leaves space for water to get in to and freeze.

They are heavy slabs so no need to lay them on a wet mix.
If they are plain grey council slabs then you can lay them on sharp sand but since you have a mixer you're best running some cement through it to stiffen it up, go for 10:1 it will be hard enough and it will save you money over something like 6:1.

Never had one crack. By the time it's tapped level the five blobs become one congealed mass.

As for rodents, well they'll dig through sand far easier than anything else. Ants too for that matter, had two big nests under flags previously laid on a sand mix, that was only disposed of by digging them up and blitzing them. The flags were blobbed back down and haven't re-nested to date.

Each have their own preferred method, but for me, blobbing is less fiddley and it's never moved or been any issue.

bobhawke

Tucker wrote: »

Never had one crack. By the time it's tapped level the five blobs become one congealed mass.

As for rodents, well they'll dig through sand far easier than anything else. Ants too for that matter, had two big nests under flags previously laid on a sand mix, that was only disposed of by digging them up and blitzing them. The flags were blobbed back down and haven't re-nested to date.

Each have their own preferred method, but for me, blobbing is less fiddley and it's never moved or been any issue.

I think I'll trust the experts on this one:
http://www.pavingexpert.com/layflag1.htm#spot

Tucker

His photo's are nonesense!

The pictures of slabs laid on a wet mix are dropped on loose sand that's all over the place. The blobs aren't even on the corners, but in the middle of the slabs. Looks more like they've been laid onto Southport beach! What tosh!

Mine are laid onto 6 inch of well compacted MOT. A world apart from that scaremongering drivvel.

Are you on commision?

bobhawke

Tucker wrote: »

His photo's are nonesense!

The pictures of slabs laid on a wet mix are dropped on loose sand that's all over the place. The blobs aren't even on the corners, but in the middle of the slabs. Looks more like they've been laid onto Southport beach! What tosh!

Mine are laid onto 6 inch of well compacted MOT. A world apart from that scaremongering drivvel.

Are you on commision?

I'm guessing that he used those pictures because they are the best example of poor paving. There are 5 blobs of mortar in those photos, one in each corner and 1 in the middle. The sub base is irrelevant because laying in that method is stupid for the reasons quoted on that site.
Why would you lay them on 150mm of hardcore? that is enough for a heavy car to use regularly and i really can't understand why you would way over engineer the subbase then make such an awful mess laying the slabs

Tucker

They look superb and lasted using the same method for 14 years before I built my extension where they used to be, so they were lifted and relaid.

The sub base was determined by the amout I needed to raise the overall height.

And of course council paving laid the way they are recommending never moves does it?

Hmmm, I wonder why there are many thousands of trip claims each year resulting from un-even pavements laid on a sharp sand mix?

aliasojo

Spent the day laying slabs, went for a dry mix of sand/cement in the end.

Tried 27col's tip and it made things so much easier, I wished I'd known that years ago. Turns out we'd thrown the ratchet strap out so we used the thin nylon straps that the pallet of slabs were bound with. Made a heavy and awkward job so much more manageable and we were able to lift the slabs into place with much less hassle.

I'm still knackered though.

27col

I expect that a lot of the problems with Council laid paving slabs is due to heavy traffic going onto the pavements.

Tucker

Maybe so, but that needs to be expected.

Either way, laying them that way costs us many millions in claims......... and keeps the supposed experts busy with future work!! hummmmmmm the cynic in me wonders!

bobhawke

The ones the council lay on a bound bedding, as recommended by paving expert, are fine after years.

As for your slabbing... an isolated case isn't the norm. The guys on that site I posted have laid tens of thousands of slabs, I think they know what they are talking about.

If there are any gaps or hollows in the bedding layer of your slabs then dropping something could shatter the slabs.

bennybroadbean

plumb1 wrote: »

Lay them on a solid base of 6 sharp sand to 1 cement dry mix. The dampness in the ground and sand will be enough to set the mix.

Agreed! :beer: