Basement Building Products Page

waterproof guarantee basement construction build manage
  waterproof guarantee basement construction build manage

Too many UK suppliers buy cheap and sell expensive.

We weren't satisfied with the best of the rest available here so we import our own where it makes our work easier and better.

These are all products widely used in countries that use much more concrete than us.

Available, in most cases only, from Basement Expert Ltd

Probably for less money than inferior alternatives.

Contact Us links at the bottom of the page. Find out about our Self Build Waterproof Guarantee.

Chemicals that do exactly what they say - without the inflated prices typical of chemical companies.

The best vibrating pokers.
Best because there is no separate engine or motor
and no moving parts in the 6m hose.

Threaded FRP rods and nuts so you leave no holes to repair in otherwise waterproof concrete.
  1. Walls. No holes left to repair or worry about.
  2. Slabs. Levelling kits that greatly reduce the amount of concrete you move by hand.
External drainage membrane.
Just a commodity at just a commodity price.
Yet strong and robust.

Waterproof Concrete Guarantee. You buy our chemicals, supervision and poker hire. We give you a 12 year warranty that we will stop any visible ingress of water.
waterproof readymix concrete th
Waterproof readymix concrete

basement concrete pump over house th
Pump-Save retarder

mixing waterproof concrete on site th
Waterproofer for hand mixes

best vibrating poker
World's best vibrating poker

frp formwork threaded rod
FRP formwork threaded rod

FRP formwork nuts
FRP formwork nuts

slab level
Slab level

external drainage membrane
External drainage membrane

Powder to make drum-delivered readymix concrete* waterproof.

Proven to BS EN 12390 part 8 to be completely impermeable, as defined by BS EN 206-1 which is the Standard for making concrete.

  1. We come to you, we put the admixture in the concrete*, we supervise your team as best we can. If they listen and do as they are told we guarantee the structure created to be free of visible water ingress. Else we will repair leaks FOC.
    Price £23 per m³, plus £300 supervision, plus £80 poker hire plus VAT**.

  2. We send you the powder and you put it in*.
    Price £23.00 per m³ plus delivery and VAT.
    Please don't think this is easy. You have to cope with varying concrete throughout the day and carefully count every revolution of the truck to make sure it is mixed. You have to cope with delays between concrete trucks; and of course we give no guarantee.
waterproof readymix concrete th
Our price is a little less than other admixtures but our service and guarantee are a 100 times better because we guarantee your workmanship if you followed our advice. No one else does, they only guarantee their chemical to the value of their chemical - even if they attend site and watch. Even if their chemical does nothing of value so you could never prove it had not worked.

They would also get you to spend a lot of money on something to go in the joints. If your workmanship is bad these extras don't work anyway. If your workmanship is good you don't need them. So listening to us and doing as we say will save you money as well as avoid leaks.
Click here to open the Material Safety Data Sheet for this powder.
* The concrete purchased must be the mix we prescribe.
over sanded for pumping
target slump before additive 60mm
no other additives

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, this will be done for you by the pump operator who will toss the sachets in from the back of his pump truck.

** Subject to minimum amounts per visit, depending on travel distance

We have a lot more information on another web site: Waterproof Concrete
We quote science, academic research and books found in university libraries. Concrete with extra cement and less water* will be waterproof if it is properly placed, compacted, cured and reinforced.

It is the concrete that will be waterproof, not the admixture. As such a BBA product certificate is not appropriate and we do not have one.

Products BBA certificates for water resisting admixtures prove just how little these chemicals do. We now know that if the authorities had read the BBA certificates for the cladding and insulation used on the Grenfell Tower that they would have realised that the products were not certified for the use they were put to.

It is just the same with admixtures for concrete that suggest they reduce water ingress. If the BBA certificates are read and understood in full, no one would put their reputation on the line choosing any of them.
More on the Waterproof Concrete web site.

It is time that the authorities tested the products more in the situation they have been used. Concrete is all made to BS EN 206-1, which refers to BS EN 12390 for strength and permeability (not BBA certificates).

Many, many large sites routinely test concrete for strength to BS EN 12390 part 3.

We get concrete tested to BS EN 12390 part 8 as well. Depth of penetration of water under pressure on concrete. The pressure is equivalent to a depth under water of 30m and the pressure is maintained for 96 hours.

Click on either image to the left to see two original test certificates.
  concrete compressive strength report to BS EN 12390 3 concrete permeability report to BS EN 12390 8

If you buy the sachets of powder to put in yourself, you need to know that each sachet is sufficient for 2 cubic metres of concrete.

You need to mix the powder for 6 revolutions per cubic metre.

So, if you have 8 metres in a truck you need to add 4 sachets and mix them in for 48 revolutions.

You must count the revolutions yourself because you cannot trust anyone else to insist that the mixing is done properly.

Proper mixing is essential, or else you will get some concrete with too much additive that will be too runny and the pressure of the pump will push the liquid forward and leave the stones dry, and stuck very firmly indeed, in the pipes.

When the driver complains about cost of diesel, look him straight in the eye and tell him you have paid for mixing. Tell him to mix it or take it away.

If the concrete is still fairly stiff, add a tiny bit of water. Only 5 litres. Mix about 10 revolutions. Once there is enough water the concrete will pour over the drum fins instead of breaking apart. That is when it is ready to use.

You should not be persuaded to add even more water to make the concrete even runnier because then you will lose essential grout out of gaps in your formwork and the concrete won't be waterproof. You need all the sand and cement to get the required density. (Don't worry about a thin dribble, but worry about losing half a shovel full.)

Mixing concrete on site and making it waterproof.

You will need to make some gauges. I use two buckets for the ballast and a pot for the sharp sand. I cut bags of cement in half with a hand saw.
Click here to open a print version of these instructions.
A typical batch will be
30 litres of ballast
2 litres of sharp sand
half a bag of cement
start with 2 litres of water
correct dose of liquid admixture purchased from us.

The above mix will make 30 litres of concrete since the fine sand, cement and water will fill the spaces between the larger stones rather than increasing the volume of the concrete.

You will get a measure with your liquid admixture. You need to add a minimum of 500ml per cubic metre.

Therefore, in the mix above, you add 30 divided by 1000 times 500. A minimum of 15ml.

Add more water very slowly until the concrete flows, but is not runny, in the mixer.
mixing waterproof concrete on site th

Mixing concrete by hand is very expensive compared to full loads of readymix. You should probably only mix by hand where readymix would be too much at once unless you paid a lot extra for a small delivery or extra time on site.

There is no need to buy retarder for hand mixed concrete.

Wash the mixer every hour so that it is easy to keep clean.

Price Each litre of waterproofing plasticiser for hand mixed concrete, sufficient for at least 1 cubic metre, is £5.

All these prices subject to delivery at cost and VAT.
Click here to open the Material Safety Data Sheet for this liquid.
Call me or email me and I can send you a quote.

Retarding the concrete in the pump waiting till the next truck arrives.

Concrete left too long before the next truck arrives can start to set.

If it does, you won't be able to compact it properly when it eventually goes in the wall.

Pump-Save retarder is a blend batched in small soluble paper bags with the correct dose for maximum retardation of half a cubic metre of waterproof concrete* mix.

The problem is that by the time a truck leaves site, the concrete it left in the pump hopper and in the pump's pipes is already over an hour old. If the next truck doesn't arrive for another hour that concrete in the pump is out of time. It has started to set.

  1. The pump operator adds a huge amount of water, so the concrete has lost strength and cannot be waterproof.

  2. The concrete has gone stiff and although it might pump it won't compact.

You retard concrete with just the right amount of retarder.
Just the right amount will retard the set for more than 2 hours.

Too little and nothing much will happen.

Too much and very little will happen.

Much too much and you have a disaster, the concrete will set quite quickly, and you don't want the bill for a written-off concrete pump.

So being accurate with the dose is quite important. That is why our small bags are so useful.
basement concrete pump over house th

pump save concrete retarder

retard concrete in pump

You need to judge when there is half a cubic metre of concrete still in the truck's drum. The driver will show you how to tap the drum. Stop the pump and add the retarder. Mix for 10 revolutions then carry on.

If there is a bit less or a bit more concrete than half a cubic metre you will still get retardation.

If you want to retard more concrete, then measure the amount of concrete as best you can and add a bag for each half cubic metre to the nearest half cubic metre you measured. Mix at least 10 revolutions or 2 revolutions for each bag you added, if more.
Click here to open the Material Safety Data Sheet for this product.
Price £4.50 per sachet plus delivery and VAT.

You could buy waterproofed concrete with retarder already in it. Such as Xypex. But if all your concrete is retarded for most of the day your formwork will be under much greater strain and more likely to burst.
It is helpful if most of your concrete sets soon after it is placed and compacted because then it is stabilised as more weight goes on top, you won't be losing a lot of grout out of small gaps which would prevent your concrete being waterproof.

So retarding only the concrete left in the pump waiting for the next load is ideal.

High Frequency Internal Vibrators. 110V.   The World's Best Type.

These pokers have all the moving parts in the head. The hose only contains a cable.

Why the world's best?

  1. Massive half tonne of excitation force. Effective diameter 800mm.

  2. The head and hose weigh about 7kgs. That's a third the weight of flex-driven poker heads.
That means less knackering. That means that the job gets done better.

It means no arm/hand vibration and it means low noise level.

concrete poker

  1. One man operation. No one needed to move a petrol engine, or stop it falling off a scaffold.

  2. The poker hangs straight. Does not catch behind the rebar in a wall pour, unlike flex drives that never straighten after being stored rolled up.

  3. German design. Made in China. Market leader in the largest concrete market in the world.

Only a cable is in the rubber hose and that is designed to stretch harmlessly when the poker is packed away badly folded up.

So it will last far longer than most electric or petrol driven pokers, you only need one man not two, it is more powerful and easier to use - and it won't stick like air driven pokers.

52mm diameter only.

Either remote control or the switch on the box.
best vibrating poker

We always use the remote control version because then the supervisor decides when enough is enough.

£700 plus delivery and VAT.

Remote control switch £30 extra.
concrete poker remote switch

Rods. These are the best things we sell.

first basement wall pour

18mm dia FRP threaded rods. Stronger in tension than equivalent steel.

Used only once. Cast in the concrete.

  1. Waterproof through waterproof concrete because they leave no holes.

  2. Make forming podium deck edge forms much easier.

  3. Can be resin-anchored into concrete underpinning and concrete piles to make double-sided formwork with only one more side.

  4. Offcuts and remnants of nuts can be used as a slab levelling system.
We have a comprehensive Product Data Sheet available here to print.

Having a rod cast in can make some situations, like a podium floor over a basement, 100 times easier.

Resin the rods into concrete piles and you have two sided formwork not single sided.

We tend to use timber instead of ply. We get more uses out of it, we don't need 4x2 stiffeners and we use roof batten layers so that we don't drill holes. It is easier, we find, to use rods with thin nuts inside to control the wall width if we use timber rather than ply. Treated 6x2 about 3m long is fast and lightweight and doesn't need as much release oil.


The rods are just cut off with a disc cutter or angle grinder when they aren't needed any more. leaving a wall without any holes to repairs or worry about.
FRP rod cut flush batten for holes

These rods work just as well with plywood or hired pans.

We find them fantastic for concreting against CFA piles because you don't need single sided shutters. But be mindful that pile concrete isn't always very strong. Use plenty of rods and consider pouring in at least two lifts.

mabey formwork    waterproof concrete basement and poolwaterproof basement FRP threaded rods
frp threaded rods for formwork

FRP threaded formwork rods podium deck

FRP rods in concrete piles

frp threaded rods for formwork

Sometimes the ability to leave a rod cast in to use again is priceless.

Price Rods are 2m long and can be cut to get the best use out of them. £7 a rod plus delivery and VAT.

Nuts for our 18mm dia FRP threaded rods.

New nuts are about 75mm long. They can be used a number of times. The quick way to remove them is to slice them off close to the formwork.

  1. You want to use the rod again after the concrete has set around it. For instance, it was used in the wall form, now it will support the podium deck edge above.
    You must use two whole nuts so that they will screw off. Use the rod and the nuts again.

  2. You won't use the rods again.
    Use a whole nut to begin with. Cut it off close to the waler plate and re-use the large part. Repeat about 5 times.
FRP formwork nuts
  1. You want to keep the wall forms the correct distance apart.
    Slice 8mm to 10mm off whole nuts and use them inside the forms to push apart like plastic tube.
Cut nuts with a diamond blade. Wear an effective face mask. Wind your nuts onto a rod and hold the rod down firmly with your foot. Take care.

Price £2.20 each plus delivery and VAT.

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.

Just a suggestion, the Screwfix code for the quick-setting resin we use is Rawlplug-R-Ker code 85750

External Drainage Membrane.

We have a Product Data Sheet available here to print.

Youtube video here. It is 7 years old so a bit out of date. But it might be useful to you.

The membrane we have in stock at the moment is particularly tough, yet cheap.

Comparison table:
Basement Expert Ltd Newton 410 Geodrain Wykamol Geotex Membrane
Colour and material Black HDPE Black HDPE Various. HDPE
Density 1,100g/m² 740g/m² 900g/m²
Material thickness 1mm 0.6mm
Stud depth 8mm 9.6mm 8mm

If you buy either Newton 410 or Wykamol Geotex, their instructions tell you to peel back the geotextile filter layer and overlap the studded plastic layers before overlapping the filter layers.

Both also sell you a plastic covering strip for the top to stop dirt getting down between the two layers.

But the top covering strip doesn't really work across an overlap because the dimples in the two sheets don't marry up well.

It is so much easier, and usually much more effective, to put up the studded sheet first then to cover it in full-width (usually 4.5m) geotextile membrane, simply tucking it over the top to keep the dirt out from above and having plenty at the bottom to wrap over your land drain in one go.

external drainage membrane for basement

external drainage membrane

Our rolls are 20m long. The full width is 1.9m.

We will sell you 5m, 10m or 15m for the same rate pro rata.

We will sell you bespoke lengths cut to order for the same rate plus 25%.

The width with studs is 1.8m. The flat edge at the top means a small overlap to keep the water draining correctly is very simple to achieve - much easier than trying to match up studs in two different sheets.

20m £120 each plus delivery and VAT.
15m £90 each plus delivery and VAT.
10m £60 each plus delivery and VAT.
5m £30 each plus delivery and VAT.
Other lengths £7.50 per metre plus delivery and VAT.

Please Note. You need to buy the filter membrane separately, for instance this. Keyline sell smaller packs as well.
From time to time we will have it in stock and you can ask us to include it with your order.

Call me, Phil Sacre:

01438 900303

07773 377087

Email me:

We have a number of other pages with information.

waterproof basement construction   You Must Have a Soil Report Before Design Starts   Please Ask Your Architect To Read This Page   Please Ask Your Structural Engineer To Read This Page   construction contract

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