self build waterproof basement formwork membrane concrete levelling

Slab Levelling rods and optional nuts.

Two purposes. One unique advantage.
  self build basement
  1. The more visual guide you have, the more accurately you can place concrete with just the right amount everywhere, reducing the amount of concrete you need to rake around.

  2. The more guides you have the flatter you can float your concrete.
The unique advantage of these rods is they will be waterproof within your concrete for all time.

What's happening in this photo looks all very well until you understand all the issues with it.
  1. The scaffold pole is 50mm diameter, so it exceeds the 40mm cover specified by the engineer. There is an element of cheating and not following the design is your responsibility not your engineer's.

  2. Support stools would not go through the steel. So although it looks like it will be a smooth finish, it won't be a level finish, because the poles are tied to the steel and where the steel is high the concrete will be high. Where the steel is low the concrete will be low.

  3. As the work continues, someone will have to walk through finished concrete to cut the tying wire and remove the poles.
  slab level scaffold

A much easier and better system for a basement slab costs £5 for a 2m rod that you cut into several lengths and whole nuts £1.50 each.

A basement floor slab always gets covered in insulation and screed because building regulations say so. Therefore you want it flat and level. It does not need to be a pretty finish.

slab levelling stool   Two problems with chairs for scaffold tubes
  1. They don't go in between all the rebars all the time. They won't go through spacing less than their size and they won't go through where mesh overlaps. Neither will they go through where the top mat isn't exactly over the bottom mat.

  2. Secondly a scaffold tube is 50mm diameter and the concrete cover is usually only 40mm.

I recently invented the simple solution that will also always be waterproof. A fibreglass rod with a nut on top to adjust accurately to the required concrete level. This will be fastest to set up but you sacrifice a nut.

You also have the choice of either setting rods in so their tops are top of concrete. This is quite time consuming.
Or fixing the rods so they are a little high then marking and cutting them down so the top of the rod is your level.

The rod might be an offcut if you used my products before.
  nut leveller

18mm diameter threaded rods made with fibreglass. You only need to get a long drill bit through the steel. I suggest 2m centres.

If you need to lay your concrete to a slight, controlled fall, say to a sump, then these rods will be invaluable.

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