self build waterproof basement formwork membrane concrete rods

Slab Levelling rods and optional nuts.

Two purposes.
  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.
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 £7 for a 2m rod that you cut into several lengths and whole nuts £2.20 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.

We 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.

You have the choice of the top of the nut being top of concrete, so the nut will be cast in and sacrificed.
Or taking more care drilling and fixing the rods so that the top of the rod is your level.

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

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

Most formwork carpenters work with steel threaded rods through plastic tube.

The length of the plastic determines the wall thickness so the tubes are cut to that length.

The steel threaded rod gets used time and time again.

Cheap for the formwork carpenters .....

      But they don't have to fill the holes up.

      They don't have to find and cure leaks months later.

What you can see in this photo is a course of timber formwork and the man working for this self builder in the Cotswolds is nailing down a bit of batten between rods because that forms his holes without drilling holes.

A 6mm piece has been cut off the ends of nuts to make thin nuts that are adjusted to the thickness of the wall concrete.

Then the next board will go straight on top.

The boards already up on the inside are screwed to a triangular brace that was screwed to the floor first.

The brace keeps everything upright and in the correct position. The thin nuts keep the wall the correct width.

The best formwork carpenters took years to learn how to use steel threaded rods successfully and they command £300 a day in some places. If you aren't that experienced you will have much more success with my formwork and fibreglass rods.
frp threaded rods

The most popular way to use nuts is just one nut on each end of the rod and to cut that off with a mini angle grinder and thin blade when the formwork comes down.

Rods. £2.50 per m.

Available mostly in 2m lengths. Also a few at 4m, 800mm and 600mm.

These were £3.50 per m but they are on sale until they have all gone. I have 5,000m or so as at 1.1.2018.

Nuts. £1.50 each.

These were £2.20 per m but they are on sale until they have all gone. I have about 4,000 or so as at 1.1.2018.

07773 377087 or

But don't cut the rod and nut off too quickly.

Plan what you do next.

If you have a corbel to form, a concrete roof to pour, or anything else that would benefit if you already have a threaded rod cast securely in the wall below, use 2 nuts so that you can get them both off and use the threaded rod again.

2 frp nuts   reuse frp rods