Concrete rebar/mesh supports choice and spacing

[SuperPav]

Hoping to get the blinding levelled, insulation down, mesh installed and UFH clipped next week ahead of concrete pour.

 

Approx 110mm slab, so was going to use 50mm plastic supports for the A193 mesh, but just come across "mars bars" or concrete square bars, which seem like a much easier solution, but cost a lot more! 

 

1) How many square bars per 4.8x2.4 sheet of mesh do I need? 

2) How much easier/better are they in reality than lots of plastic chairs? 

 

If it saves me a day of labour, I'll pay the extra, if not, then I won't bother. There will be a lot of walking over the mesh to get the UFH tied to it, so needs to be relatively steady.

 

Thanks!

[Adam2]

Hi we used a combination on ours. Mars bars - these are quite cheap and flexible, you break them up of course into smaller bits, when installing don't create a nice uniform line as apparently that can potentially help induce cracking so go random! We also needed metal chairs (1m & 2m lengths) at different heights to support our 2 levels of mesh in the slab. Not sure if you get 50mm mars bars but don't see why not.

 

To your questions - we just had a pallet delivered and used as many as we felt was needed for adequate support - they went a looooong way, we had about 200m2 of slab that was plenty

 

Not used plastic chairs only metal 

 

 

 

[Conor]

Mars bars or bits of broken pavers. You'll soon. Figure out how many you need once you start walking on the mesh. Min every 1200mm, double that at the edges.

[SuperPav]

Thanks both.

 

While I'm sure I'll figure out how many I need once I start doing it, that doesn't really help with ordering them to arrive with the mesh.. 

 

I've ordered 100 square bars for the 20 sheets, that should be enough I'd hope!

 

 

When you break them up, presumably it's still into lengths greater than 200mm so it spans more than one rebar?

 

If we start running low, the garage might be done using broken/cut up pavers - I've got a fair few of those kicking about too! 

[markc]

No, make the chairs (blocks) as short as possible, short pieces placed at crosses.