Laying tobermore concrete slabs

[barrymac20]

Hi all.

I hope this is correct forum.

I am installing 400x400x40 tobermore concrete paving slabs on a screeded bed. I'm just wondering should I add cement into the sharp sand or is it ok to use the sand only?
I have a 100mm 803 compacted base in place already.

Also, when laying the slabs should I be precise with have a 2-3mm gap? Tobermores documentation suggests 2-3mm but they've also told me online that I can butt joint them

Edit: I should note that the slabs are chamfered, just in case that makes any difference regarding the spacing

B

[Tony McC]

NO CEMENT!!! YOu can't have a rigid/bound bed and then have flexible/unbound sand joints. Recipe for failure.

Maintain a 2-3mm joint by simply laying the flags hand-tight and then inserting the blade of a trowel to space them.

I don;t know who at Tobermore told you butt-jointing was acceptable, because it's not, and I shall be having a word with their Technical Manager who is a good mate of mine. Someone is going 'off-script' with that spurious advice.

[barrymac20]

Makes sense. Thanks for that.

Its a pity they dont put wee nibs on their slabs. Would make it so much easier.

Ive seen other "400mm" cast slabs that are 398mm with the 2mm nibs. The tobermore ones ive got are 400mm exact with no nibs.

Kind of fecks up my dimensions as I'm putting a border of 100x100 setts that are actually 98x98. Will leave it a bit awkward as I'll need a little bigger of a gap between the setts than the slabs to line them up properly

[Tony McC]

It's a growing trend, emanating from that Europe, where Tobermore (and several other British/Irish manufacturers) obtain their moulds for licensed products, and where the professional installers are more familiar with laying 'hand-tight', which is looser than how we normally do it over here, pressing block against block and relying on the spacer nibs to generate the joint.

It's not that it's wrong: it's more that it requires a slightly higher skill level to get it right.

Call me soft, but I prefer a nibbed block!

[barrymac20]

Yep. A little more tricky without the nibs but its working out ok so far using the trowel and rubber mallet to align. Thanks for your help.