Licenced Builder (and My Home Improvements’ Managing Director) Greg Catton explains what makes a great metal roof paint, AND names names.
People often ask me what’s the best metal roof paint on the market.
It’s a fair enough question; as you’ll know if you’ve done a bit of research into iron roof restorations, metal roof paints don’t come cheap, and the last thing you’d want is one that doesn’t go the distance.
I do have the definitive answer to this question – and I’ve got to tell you that you won’t find it at Bunnings – but first let me explain WHY my number one pick is the best paint for a metal roof.
There are three factors that make a quality metal roof paint better than its competitors, and in some cases, much better. They are:
- The solids level in the paint
- The ‘breathability’ of the coating, and
- The flexibility of the metal roof paint.
Let’s look at these separately.
The best metal roof paint is high in solids.
The most important factor to consider with metal roof paint is the solids level in the coating.
Let me explain why.
You see, paint coatings are made from these main constituents:
- Pigments (solid or liquid) – the ingredients that give the coating its colour
- Binders (resin) – the ingredient that holds the pigment in place, a constituting agent
- Extender – larger pigment particles that give strength and adhesion the film
- Solvents – used to give viscosity to the coating
- Additives – used to modify the property of some of the ingredients. (For example, some coatings have in-built fungicides or biocides in them.)
All different metal roof coatings serve different purposes, however with your roof the most important facet of the system is how long the coating will hold its colour, and how well it will pull up after direct and extreme exposure to the sun and its damaging UV rays.
Many roof coatings claim to have high pigments in their coatings but this is misleading.
They achieve this by adding a higher percentage of solids (chalks) to the metal roof paint.
Unfortunately, this does not increase the lifespan of the product. On the contrary, the more solids used actually prevents the paint from being mixed into a uniform liquid.
It usually leads to an uneven and premature break down of the coating long before a high quality roof paint will start to show signs of wear and tear.
Quality metal roof paints use very high Resin Solids.
Premium metal roof paints are chockful of resin-solids.
Resin is an ultra-heavy liquid solid containing the pigment or the colours of the roof paint; the more pure the resin, the more colour-fast the paint will be.
Pure Resins offer the strongest resistance to UV light exposure, chalking and yellowing, fading, bubbling, cracking and peeling, all provided the manufacturer’s application process is stringently followed.
Resins are very expensive to buy or manufacture, so a lot of manufacturers have started to take short cuts.
In recent years, some hybrid liquid resin solids have hit the market in an attempt to reduce overall production costs yet still meet some of the more rigorous demands of roof paint coatings.
Co-Polymer or Styrene Resins are two which come to mind, but I only use Roof Coatings that offer 100% Pure Resin Solids.
As you continue your research, you will notice that the top metal roof paints – the ones that contain the most resin solids – offer the industry’s longest manufacturer’s warranty…and now you’ll know why.
The best metal roof paint is breathable.
The second most important factor of a top metal roof paint is how breathable it is.
Some people think I’ve lost it when I tell them this, but if very small water vapours are allowed to be released from underneath the coating, the longer the paint will last.
If your roof coatings system doesn’t allow a very minimal amount of moisture transfer, you could well end up with bubbling of the roof coating within months of application.
This is because inferior roof coatings tend to form impermeable skins on the outside which harden over the next 14 days.
Once this has occurred no moisture can be released from the underside of the paint.
Premium metal roof paints are breathable and allow this moisture to slowly release and give your roof coating system a longer, drier lifespan.
They also reduce the possibility of fungus growing in the tiles under your coating and drastically reducing the longevity.
The best metal roof paint is flexible.
The third aspect that makes for a superior quality metal roof paint is flexibility.
Now cheaper roof paint manufacturers will no doubt claim their product is flexible, but we need to ask what type of ingredient provides this flexibility.
If the answer is any type of migratory plasticizer this means the roof coating will initially be flexible but over the coming months the plasticizer will leach out of the paint.
This will leave it rigid and prone to degrade soon after.
100% Elastomeric Acrylic Polymers are expensive but last a life time and ensure that no matter how much your home may move over the years, so too will your metal roof coating system.
So…what IS the best metal roof paint?
I’m just a humble builder and it has taken me 15 years to understand the scientific action of paints and what determines the best product.
But now that I am more cluey about solids, breathability and flexibility, I know that the superior metal roof paint is Nutech. With daylight second.
Nutech are the only specialist roof coatings manufacturers in Australia that use the highest quality ingredients and Pure Resins…and that’s probably why they offer the longest warranty on the market.
It also so happens that my team of licenced contractors and myself understand the application process so completely, we are currently the only Certified contractors in Queensland for Nutech Roof Coatings.