The coating on the steel substrate complies with the coating classes as specified in AS 1397 – 2011: Continuous Hot Dipped Metallic Coated Steel Sheet and Strip – Coatings of Zinc, and Zinc Alloyed with Aluminium and Magnesium.

The MagnaFlow® coating comprises zinc, aluminium and magnesium and delivers more durable site performance

than standard zinc or Zinc/aluminium systems. Minimum coating mass is 240gsm.


Paint Systems


The MagnaFlow® painting systems are applied by Pacific Coil Coaters (PCC) in New Zealand, using the most up to date painting technology. PCC, like Stramit, is part of the Fletcher Building Group.


The primer is a flexible corrosion resistant chromated primer, with a nominal film thickness of 7μm ± 1μm on the top side, and 5μm ±1μm on the reverse.

Finish Coat

The finish coat can be a flexible acrylic, polyester or modified polyester coating, with a nominal film thickness of 18μm ±2μm.

MagnaFlow® X

For applications where there is a high risk of deterioration from corrosive elements, such as severe marine or industrial sites, then the MagnaFlow® X paint system could be suitable. The MagnaFlow® X paint system uses the same substrate, but comes with a more durable surface finish.

The finish coat is a Polyvinylidene Fluoride (PVDF) paint system of nominal film thickness 20μm ± 2μm, containing at least 70% resin in the dry paint film.


The backing coat is a Shadow Grey (standard colour) wash coat 5μm ±1μm.

Gloss levels are25% ± 5% measured in accordance with ASTM D523 – 14 (60 degrees)

Products can be supplied with an optional strippable film at extra cost. This material has a relatively short life span when exposed to sunlight and weather. It should be removed either just before or immediately after installation.

Animal and farm environments

Excellent resistance to ammonia and humidity make MagnaFlow® coated steel products suitable for animal barns, composting sheds and other farm buildings with harsh, damp environments and corrosive conditions caused by animal excreta.


Class 5 coated screws will give the best service life with MagnaFlow® products.

Do not use stainless steel or monel fasteners on MagnaFlow® products.

For further details refer to the SA HB 39:2015 Installation code for metal roof and wall cladding or consult your

fastening supplier.

* A warranty on MagnaFlow® product in ISO 5 is subject to prior approval by Stramit

Refer to specific warranty information for full terms and conditions, including exclusions and minimum maintenance requirements.

Buildings close to industrial areas which are be exposed to corrosive chemicals may require MagnaFlow® X paint system (for added protection

via PVDF paint). Visit and complete the warranty enquiry form.

Site practice

If nestable profiles become wet while closely stacked, formation of wet storage stain or ‘white rust’ is possible.

To minimise the possibility of inadvertent damage:

• Inspect deliveries on arrival. If moisture is present, individual sheets should be dried immediately with a clean rag and then stacked and filleted to allow air to circulate and complete the drying process.

• Well ventilated storage is essential. Always store metal products under cover in clean, well-ventilated buildings

• Cross stack or fillet sheets where outside storage is unavoidable and make provision for a fall to allow water

to run off. Cover the sheets.


Refer to the SA HB 39:2015 Installation code for metal roof and wall cladding for correct installation guidelines, particularly in regard to underlays/building papers, penetrations, flashings, fasteners, pitch etc.

Dissimilar metals

When dissimilar metals come into contact with each other, the electric potential difference between the metals establishes a corrosion cell, and accelerated corrosion can occur.

To avoid this problem, the following precautions should be observed:

• Avoid discharges of water from brass or copper pipes on to MagnaFlow® products.

• Do not use non-galvanised steel, copper, brass, lead, stainless steel or monel metal in direct contact with MagnaFlow® products.

• Do not use lead flashings in contact with MagnaFlow® products.

Sealing and jointing

Where sealed joints are required, use only neutral cure silicon rubber sealant together with mechanical fasteners such as aluminium rivets. Do not weld or solder.

Unsuitable applications

MagnaFlow® and MagnaFlow® X products are not suitable foruse in the following situations:

• For water tanks or areas where a constantly wet environment is maintained.

• In direct contact with concrete or where lime deposits are evident.

• In contact with soil (allow a 75mm run off below cladding sheets to ground level).

Touch-up paint

MagnaFlow® is a baked on paint system which has different weathering characteristics to standard air drying paints.

Do not use touch-up paint on MagnaFlow® products.

Clean up

Installation procedures involving self-drilling screws, drills and hacksaws etc will leave deposits of swarf and metal particles.

These particles including blind rivet shanks, nails and screws should be swept and washed from the roof regularly. Refer to the SA HB 39:2015 Installation code for metal roof and wall cladding. 


Outdoor durability

MagnaFlow® products under normal well washed conditions of exposure, can be expected to show no cracking (other than that which may occur during forming), flaking or peeling of the paint film for 15 years from the date of installation.

Colour change during service will depend on the colour chosen, aspect, design of the structure and the environment.

The above are subject to minimum maintenance requirements (refer to minimum maintenance section).

Minimum maintenance

The service life is extended by regular washing. A mechanical wash every six months is recommended, more often if contaminants build up. At these times inspect for damage and failing fasteners, and repair these.

Unwashed areas

These are typically those areas that are not washed by natural rainfall, such as the underside of eaves, sheltered roofs or wall cladding, under solar panels etc. These areas are excluded from warranty. Stramit recommends the exclusion of unwashed areas by design wherever possible.

In cases where this is not possible, then a regular washing programme should be put in place. Contaminants should be removed by mechanical washing with water and a soft bristle brush at least every six months, or more frequently in severe environments or if contaminant build-up keeps occurring.