self build waterproof basement formwork membrane concrete powder

Waterproofing Readymix concrete.

Powder to make drum-delivered readymix concrete* waterproof.

I sell an admixture that makes concrete waterproof.

As good as any of the rest out there.

For less money. £29 a m³ treated.

I explain a lot more on this page,
and I go into all the science on this discussion web site
  self build basement

If you are new to buying concrete I have some beginner advice here.

Usually I am also paid to supervise all the concrete pours. I will guarantee your concrete structure free of visible leaks if you buy my products and services. I will talk to your concrete supplier for you as well if you wish.

* The concrete purchased must be the mix I prescribe.
  1. P350. This means 350kg per m³. (P380 with 10mm aggregate.)

  2. I used to insist on pure OPC cement but I have had to allow blends with GGBS and PFA on occasions and never had an issue. Therefore the cement can be CEM 1, CEM 2 or CEM 3.

  3. Over sanded for pumping

  4. Target slump 60mm.

  5. No supplier additives.

  6. make it clear that a powerful plasticiser will be added and mixed in at site and the customer's consultant will ensure the concrete will be pumpable.
Click on these thumbnails to open original test certificates to the usual standard for testing hardened concrete: BS EN 12390. One is strength and the other impermeability.
Clearly strength exceeds the usual C40 and the water penetration is less than the 20mm specified in BS EN 206-1.
More here: in a text book on the subject of BS EN 206-1 and more on the page for architects as well.
concrete compressive strength report to BS EN 12390 3 concrete permeability report to BS EN 12390 8

Tell your readymix supplier that you will be adding and mixing in your own super plasticiser when the concrete arrives.
If you are asked, don't open a can of worms about Health and Safety unnecessarily. The plasticiser will be put in for you by the pump operator who will toss the sachets in from the back of his pump truck, without standing on, climbing up or even touching the concrete truck.

Let them know that it is a very powerful plasticiser so they should only put in the water for 60mm slump - less than usual.

The powder is mixed in six revolutions per cubic metre.

Keep your slab wet well into the evening to prevent it drying out too quickly.

Click here to open the Material Safety Data Sheet for this powder.

The admixture for readymix concrete can only go in drum trucks that carry concrete batched back at the batching plant. I cannot waterproof volumetric mixer concrete. Neither can anyone else unless they got a truck specially adapted to suit a particular chemical.

waterproof readymix concrete

Concrete can be made a million different ways for different advantages.

My concrete is absolutely waterproof.

But it goes stiff quickly.

You cannot usually get a perfect finish on this concrete. Perhaps if the weather is cold. Never if it is hot.

easy float slab nut leveller
  1. You are very experienced with this concrete, and

  2. You bought our slab levelling kit so that you spend very little time raking concrete around before you can try and get a float finish, and

  3. You get your concrete placed by an overhead boom pump, not by a line pump, and

  4. You have 5 hard working guys.
If you can get concrete with a cement blend, GGBS slag or PFA ash, then either should always be waterproof and you might get a little more working time.
overhead boom pump

Sometimes I get to site and there are not 5 strong men to do the work. I don't jump in and help any more. I have a minor disability and I am too old. Your concrete will probably be finished badly and I might not be willing to give you your guarantee.

From my hotel room in Bangkok I watched a huge site next door.

This slab was cast with a boom pump, which creates work. But there were 13 of them all together. Plenty of power to move concrete around quickly.

concrete bangkok

From the beginning of 2021, I VAT registered Basement Expert Ltd (Co. No. 09745193 Registered in England and Wales).

The limited company will supply all products and add VAT at 20%

I, Phillip Sacre, will provide advice free of VAT.

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