What Wacker Plate to hire?

[HComplex]

I've just finished digging a hole in my garden ready for a new paving slab shed base (12x10ft).

I'm looking to put down 150mm type 1 as a sub-base as the ground is heavy clay and the old base subsided quite a bit over the years.

I'm unsure how best to go about compacting it. I have a hand tamper, but I've been told it would be better to use a powered one to get better compaction, I'm not sure how true this is.

I've been looking at options for hiring:

Altrad Belle Plate Compactor | Speedy Hire

The Altrad Belle PCLX320 is a lightweight and robust 320mm Petrol Plate Compactor designed for compaction of hardcore and aggregate.

www.speedyservices.com

Altrad Belle PCLX12/40E Plate Compactor 50kg | Speedy Hire

The Altrad Belle PCLX12/40E is a lightweight 240v Electric Plate Compactor providing high performance compaction across all materials making this ideal for

www.speedyservices.com

Would either of these be suitable? The electric is only 1kN less force than the petrol, does this mean they'll both do a pretty equal job on it?

Never done this before so any advice would be really appreciated.

 

[^woody^]

Hand tamp will be fine. Or just hire the smaller cheapest.

150mm is excessive and won't make any difference to clay movement which begins much deeper down. But if you are so minded, whack or hand tamp in two 75mm layers .

 

[Ivor Windybottom]

I've got a cheap electric compactor. It's OK, it works pretty well. This one, which probably doesn't cost much more than hiring...

Evolution 015-0002 Hulk Electric Compactor 780W 240v - PowerToolMate

www.powertoolmate.co.uk

I'm not rubbishing it, it's very useful. But I borrowed a petrol one and it was way better.

But, besides the power, the biggest annoyance of the electric ones is the cable. You tend to go round in circles with these, as they like to go forwards only. They take a lot of effort to pull backwards and they tend to make a mess of the surface when you have to. So the cable gets in your way and ends up more twisted on each lap so ties itself in tight knots. I had to replace the cable in mine after a while after it broke internally, I guess from all this twisting.

 

[HComplex]

Hand tamp will be fine. Or just hire the smaller cheapest.

150mm is excessive and won't make any difference to clay movement which begins much deeper down. But if you are so minded, whack or hand tamp in two 75mm layers .

What depths would you recommend?

Current plan is 150mm type 1, 40mm sand/cement mix with 50mm slabs on top. I got this from the website I'm buying the shed from, but there's a lot of conflicting info online.

Is there any way to mitigate the clay soil effects without digging down really deep?

 

[^woody^]

Don't worry about clay movement. If anything at all, it moves evenly and little.

You only need to remove the soft soil later, so for a slab base, 100mm of hardcore should be more than enough.

 

[noseall]

Is there any way to mitigate the clay soil effects without digging down really deep?

What effects are you worried about? Any surface issues can be dealt with using hard core etc.

Deeper clay issues only affect things enclosed, such as trench foundations and concrete floors etc.

 

[HComplex]

I'm only worried about the slabs sinking unevenly like the old base did causing the shed to lean. The last base only had about 30mm dry sand cement mix with slabs laid on top (no hardcore), so I'd just like something a bit better than that.

I don't want to go over the top though...

Thanks for the advice all, very helpful.

 

[noseall]

I don't want to go over the top though...

Adding too much hardcore can present its own issues. Stick with 100-150mm.

 

[robinbanks]

You tend to go round in circles with these, as they like to go forwards only

Or you can walk one way, then turn around and walk the other way, next to the way you just walked (like you would if you were mowing stripes into a garden)

 

[Ivor Windybottom]

Yeah, but that means you're turning 180 degrees every time, rather than 90 if you go round in squircles. These things don't really like turning, they just want to go in a straight line for ever. Plus if you're against a wall or fence then you'd be trying to put the handle in a place that doesn't exist. One of those ideas that sounds fine until you actually try it in reality.

I'd say the electric one is fine for garden paths, but I was glad to use the petrol one for my shed floor. It performed better, but the lack of cable annoyance was also a big plus.

Whatever the type, definitely keep the layers thin. There's no penalty for over-compacting, the more squashed the better. The petrol one used almost no fuel, you can get a 5L tin and take as long as you like, you'll still end up chucking the leftovers into your car however much you mess about.

 

[^woody^]

In tight corners or ends of runs, you guide it via the machine, not the handle.

 

[Ivor Windybottom]

The machine? What, kick it?

I was using mine within a foundation, with the walls built up to DPC. I ended up mostly holding it back to stop it trying to smash through the walls!

Would be much easier on a flat area where you can go beyond the end and turn around on the surrounding area.

 

[robinbanks]

One of those ideas that sounds fine until you actually try it in reality

It's electric, and very easy to on/off. It will drag easily when off. To turn 180 you can walk backwards and in a small semicircle if you're up against a wall (you thus circle away from the wall)