Putting down a concrete slab, what timbers to use?

4x2’s would Be fine, anything bigger would be a waste of money, get a few lengths of 10 / 12mm bar and cut them up maybe about 300mm long, drive them in along the 4x2’s to keep them straight, drive a 3 inch nail at both sides of the bar and bend the last inch of each nail around the back of the bar and she won’t budge. Go to the hardware with a trailer if you can and pick out the straightest of the lengths yourself

Ya 6 x 3 for speed and straightness but not really economical for a one off use. 4 x 2 will do the job but they will bend in all directions so you need to be super careful in supporting them.

if you can let in a bit of dryer mix around the timbers before you wet it up, it’s a good job too.

You will need a 6 inch slab if it's for a shed.

4 inch is liable to crack and break away at pressure points even if it is down on a slab of rock.

this is all 100% correct. You’ll be left with a pile of cracked broken up concrete if putting 100mm straight onto rock. Complete waste of time and money. You’d be as well off tipping a few loads of gravel for the floor of the shed and pouring pads for the columns.

tamping😯

General run is 7 on the ordinary truck

25 Newton is very weak their is not much cement in that you won't have a great finish 30 Newton is even weak your surface won't last even where their is no effluent on it I am not sure whether the price is dear or not

I was quoted 140 in Galway a few weeks back for 35N. Thought it good value

Newton in concrete is the 28 day crushing strength lads don't understand that their are many ways of ensuring their concrete passes a 28 day test their is no such thing as a standard way of mixing concrete for quarries but in a 25 n mix out of a limestone quarry their is not much cement but when you look for 30 or 35 their is substancilly more cement most of the time their is no comparison

might be cheaper than some places but considering that would have been mid 70s a few years ago I wouldn’t call it value!

Yeah not sustainable & the yearly carbon tax is just goin to keep it climbing

footpaths should be a 10mm chip with extra sand, roadstone are now charging extra for both the b****rds. Screw the laser receiver onto the placer it’ll save someone else going around telling you to go up and down, you can check yourself as you go. Also I’d go I’d go stronger than 25N if I were you, it’ll cost a thing of nothing extra for the amount of concrete you’re using.