Construction World October 2016

CONSTRUCTION WORLD

OCTOBER

2016

However, in Europe, Torch-on

systems are now declining in the

USA, while Torch-on membranes

have substantially lost ground to

T.P.O. (thermoplastic polyolefin) membranes

which now claims around 40% market share,

followed by E.P.D.M. (ethylene propylene

diene terpolymer) membranes. Torch-on

membranes, in fact, represent only about

20% of the USA market.

The South African specification market

also seems to be changing with an increase

in the use of additives to the concrete mixes

and liquid waterproofing coatings. Some of

these systems, which have been around long

enough to have verifiable performance track

records, are fast replacing the traditional

Torch-on application.

The use of additives in a concrete mix

to render the mix waterproof and watertight

has proven successful in both below ground

and water containment environments. There

are two principal areas of technology and

products in this field: crystalline-based such

as Chryso SA’s CWA 10 crystalline water-

proofing admixtures, or the a.b.e. Construc-

tion Chemicals Pore Blocking system, Fuge

B, a hydrophobic additive applied during

the concrete mix stage to block pores in the

concrete to prevent water passage.

There are benefits to be had from the

correct application and in the appropriate

situation with both these products – but it is

important to fully understand the effects of

the two systems before specifying or using

these products. Crystalline-treated concrete

will react when a crack occurs and is exposed

to water by forming crystals in the crack

and so, over a period of time, it will render

the crack leak-free – as long as the crack is

static. A dynamic crack would require further

treatment. Pore blocking, as stated, restricts

water ingress to the cured concrete among

other advantages.

Then there are also Polyurethane, Poly-

urea and hybrid products making their pres-

ence felt in both the international and local

markets. So what is the difference between

polyurethane and Polyurea? A waterproofing

industry expert once aptly described

Polyurea as ‘a polyurethane on steroids to

provide an all-round superior performance’.

There are ongoing industry develop-

ments where hybrid products are being

formulated for possible use in the water-

proofing industry but, for now, let us focus on

Polyurea and polyurethane.

A well specified, properly applied Poly-

urea system invariably produces a first-class

result but sometimes a Polyurea specification

falls into the waterproofing section of the

Bill of Quantities. The problem now is that

not many traditional, long-established

waterproofers own the necessary plant and

equipment – or indeed the technical and

mechanical skills – to achieve the desired

end-result when applying a relatively

complex Polyurea system.

For this, application is made under high

pressure with the heated components being

brought together at the nozzle of the spray

gun and sprayed to a defined thickness.

Curing time can vary from seconds to

12 minutes. Polyurea is generally UV-re-

sistant, has very good elongation charac-

teristics and, in buried situations, is root

resistant. Not all Polyureas are the same,

however, and in this regard a.b.e. is fortunate

to have Polyurea systems developed by the

globally-respected German producer, VIP, at

its disposal for local distribution.

Polyurethane and hybrid waterproofing

systems can usually be applied by brush,

roller or low-pressure spray and are easier to

apply and have more forgiving requirements

when it comes to substrate strength and

surface profiles but the end-result is never

equivalent to a Polyurea system.

That, briefly, sums up the waterproofing

options available in South Africa today. But

waterproofing is a rapidly changing and

complex environment so, to avoid confusion

and disastrous results, it is always wise to

consult the experts before specifying or

starting any project. Both a.b.e. Construc-

tion Chemicals – which has been involved

in waterproofing for over 80 years – and its

holding company, Chryso SA, have the tech-

nological experience and expertise to help in

this regard.

Modern waterproofing systems today

offers both the traditional torch-on membrane

coatings as well as the relatively new high-

tech Polyurea roof and deck protection.

PRODUCTS AND SERVICES

WATERPROOFING

new era in SA

By Gordon Anderson, Waterproofing Consultant at a.b.e. Construction Chemicals.

For the past 30 years, the South African and European

waterproofing markets have been dominated by factory-

produced ‘Torch-on’ membranes, containing various modifiers.

The usage of Torch-on membranes currently represents over of

70% of the local waterproofing market.