Auckland City Rail Link

Auckland City Rail Link

Alumat 15DO extra heavy duty drainage matting chosen for Auckland City Rail Link

After evaluating all options, Alumat 15 DO entrance matting was selected for the entrance ways of the new underground rail stations in Auckland.

The need was specific.  A product that could withstand heavy duty traffic.  Of special importance was a system that could catch, contain and dispose of surface water at the points of entry.

After searching of all possibilities, only Alumat 15 DO was considered capable of meeting all requirements.

The three new stations with multiple entrances will have Alumat 15 DO entrance matting, coupled with a grating system that discharges the surface water, under the mat, where it can be collected and discharge.

Alumat 15 DO is unique.  It so effective, it can catch, contain and dispose of continuous running surface water, unlike any other entrance matting system.

Installation expected early 2024.

Product Used

Alumat 15 DO

Product Range

View our full range of flooring solutions.


The purpose of entrance matting in commercial properties, apart from looking attractive and welcoming, is to keep interior flooring clean and dry.  Keeping floors dry is an essential requirement for safety, especially on interior flooring that may become slippery when wet.  Not all entrance mats will do the job.  One size doesn’t fit all.

Alumat offer three types, with a number of options within each type,  to meet every need.


In most situations, that is accomplished with use of any reputable brand of entrance mat that complies with safety regulations, including fire safety standards.  Aluminium bar and textile infill products work well, as they absorb moisture from footwear.  Alumat offers a range of different mats that do this very well, including the standard Alumat 10 IAlumat 10W, and the deeper Alumat 15 I mat options.

If though, the amount of water is too much, the fibres will reach a point that they cannot absorb any more, and the drying effect on footwear ceases.  Some textile fibres may be considered more absorbent, but when stepped on, the weight applied simply releases the water.

To deal with this problem, Alumat have produced 2 new types of aluminium and infill entrance mats that will handle any amount of surface water, keeping interior floors.


Where there is only a moderate amount of additional water to deal with, what is needed is a mat that can contain surface water away from foot traffic, where it can remain until the water evaporates.  Alumat closed drain channel mats ( Alumat 10D, Alumat 10WD, Alumat 15D and Alumat 15WD) all have textile infill strips alternating with closed water drainage channels at the base of the mat.  The water can collect without coming in contact with foot traffic.  In most cases, these four mat types, are more than adequate.


In some situations the surface water or exposure to the elements requires more.  Any mat that becomes water logged, will cease to function as intended, and the only way to deal with this is to REMOVE the water.  Alumat have developed three new mats, that do this very effectively and can process the removal of over 800 litres of surface water per square meter every minute.

The mats are Alumat 10DO, Alumat 10WDO and Alumat 15DO.  See also drainage design

These mats have textile fibre strips, alternating with water drain channels that discharge water under the mat.  Usually placed on permeable grating over a drained catchment area.


During 2022, Alumat was approached by City Rail Link looking for a solution for a situation they were dealing with.

The underground rail system had three stations, with a number of different entrances leading to escalators.  The entrances needed to be able to handle high volumes of foot traffic.  Many commercial entrance mat types would usually suffice.

However, surface water entering the underground rail stations was a special concern that needed a special solution.  A variety of matting options were considered, and the mat deemed to be the best available was put forward.

Unfortunately, it too, was incapable of handling the excessive water that the entrances may be subject to, so the team looked further.

Alumat Flooring Solutions was contacted in the hope that they may have a suitable product.

Alumat Open Draining Mats were recommended, and it became evident that this would be the ideal mat for this situation.

The product selected was Alumat 15DO.

What makes Alumat 15DO special, is it is specifically designed to extract surface water.  In fact 15DO mats can extract over 800 litres of water, per square meter, in just one minute.  More than enough for the water capacity expected.  We are unaware of any other matting system anywhere that comes close to this performance.

15DO is also an extra heavy duty mat, with frames built to last, with a 20 year warranty

While the features were enough to convince the selectors at City Rail Link, an added bonus was cost saving over other products considered.

How does it work?

The drain channels alternating with textile fibre insert strips, have a series of drain holes.  Each square meter has 180 of these, each 10mm x 20mm.

In the City Rail Link project, the mat is placed on a supported rigid and permeable grating.  Under the grating there is a waterproofed and drained chamber where the diverted surface water is collected, and taken away via the drainage system.

Alumat would be pleased to assist any designers with practicalities of this type of design and share any observations they can.

For any commercial entrance way matting needs, contact Alumat Flooring Solutions.  We likely will have just what you need, and like City Rail Link discovered, you may find a far superior product at a better price.