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Flaking Roof Paint: Why It Happens & What To Do About It

Flaking Roof Paint: Why It Happens & What To Do About It

It’s only been a few months and the paint on your roof has already begun to peel. You feel it in your gut that shouldn’t be happening but you’re not sure if you should ask for a do-over.

Properly applied roof paint should last you for years, giving your roof and the building plenty of curb side appeal. If not, something has gone wrong.

Here’s what’s happening and what you can do about it.

Peeling of Painted Roof Tiles

Why Tile Roofs Flake

Most roof paint flakes due to bad prep, including:

  • sloppy surface cleaning
  • bad primers
  • incorrect products
  • painting in the wrong temperature

If the painting was done over debris, the paint won’t stick. That also tends to happen if a cracked tile is painted over instead of replaced. Dirty and damaged roof tiles are the two biggest causes of paint peeling.

The tile surface should be given as much attention as it takes so it’s perfectly clean and the paint coat can fully connect to it. Pressure cleaning of roof tiles should be done with at least 3,000 PSI of pressure, which domestic pressure cleaners can’t achieve. Otherwise, you won’t be able to get out the deeply seated dirt, weeds, moss and even algae, which can actually grow on glass if conditions permit.

We use pressure cleaners that can put out up to 3,500 PSI to get the job done. The sheer power of the water jet blasts away all debris and leaves a clean, though chalky surface. This is because roof tiles lose their glaze and become chalky after 10 years or so in the sun, absorbing moisture and slowly losing structural integrity.

The ends of tiles should be given special attention to clean them through and through. When we get up on a tile roof, we first check the tile ends; if they’re black, we know the previous cleaning job has been botched.

We know why amateur contractors avoid cleaning the tile ends — incorrect handling of the pressure cleaner can push the water underneath the tile and flood the ceiling. The key to doing it correctly is that we aim the water jet at a certain angle and never linger on a single spot. That means the grime gets blasted off without any risk of flooding.

 

 

Flaking Roof Paint

 

 

What To Do When Your Roof Tiles Flake

Make a catalogue of all products used on your roof, including roof tiles, and follow as many manufacturer recommendations as you can. First, figure out what the roof tile manufacturer recommends. Then, find out the best product in accordance with those recommendations and then follow the recommendations for it. That should help minimise or even eliminate flaking. Get it all in writing so you don’t get lost later on.

Still, all the recommendations don’t mean much unless you have practical experience with roofs, tiles and roof tile primers and paints. There’s only so much you can learn from online forums or by talking to roofers; what you need is an expert on the scene.

For some tile types, such as for slate tiles, it’s very difficult to prevent flaking. It’s a known fragile stone that especially can’t withstand rapid freezing and thawing. The moisture trapped inside the stone will rapidly contract and expand, building up the pressure inside the material that will cause constant flaking.

Keep in mind terracotta roof tiles can’t be painted for a number of reasons we have discussed previously on our blog. In short, the material they’re made of prevents the paint from bonding, though they can be glazed. Get in touch with a terracotta roof tile expert and discuss your options to minimise the damage the tiles will take.

 

Flaking Roof Paint Why It Happens and What To Do About It

 

How To Prevent Flaking Roof Paint on Your Tiles

Bad painting conditions are the primary cause of roof paint flaking, closely followed by subpar products and sloppy product application. You should give more time for the paint to settle in humid conditions or in the searing sun. You don’t have to and the paint might hold but its lifespan will be shortened. Protect the roof up to 48 hours after painting if there’s a chance of dew, frost or rain.

There shouldn’t be any insects on the roof and there shouldn’t be any strong wind either. As a rule of thumb, products from the same manufacturer are designed to work with one another. Products can work across brands but the contractor has to know what he’s doing.

A proper cleaning, priming and painting job should prevent the roof paint from flaking for up to 10 years, which is why we provide a 10-year workmanship warranty for all tile painting jobs.

 

Vivify Roofing Colorbond

 

 

Peeling of Painted Colorbond or Metal Roof Tiles

Metal is more durable than any other roof material but also has a slightly different set of rules for painting. For metal roofs, the correct installation makes a much bigger difference than with tile roofs because they’re harder to repair. When one or more tiles crack, they can be replaced at practically no cost, but damage to a metal roof means the entire section should be replaced.

Why Metal Roofs Flake

In the best case scenario, the cause is merely that the primer and/or paint are incorrectly applied or that they have expired. In the worst case scenario, the cause is structural weakness of the roof or that it has approached the end of its usability cycle.

Even the slightest dents in the structure of the roof might mean that’s where water will pool. As soon as you have pooling water, it’s only a matter of time before it starts seeping beneath the paint, leading to flakes.

What To Do When Your Metal Roof Flakes

We suggest you don’t spend too much time or money on quick fixes. When a metal roof experiences flaking paint, it’s time for a serious do-over, not a quick fix that will again fail in a few months’ time. Metal roofs do not tolerate patch jobs, since the patching lines are where water can easily seep through the roof.

The roof should be stripped bare before applying a primer and then repainting. However, we recommend replacing the roof completely. This is because modern metal roofs are imbued with several durable coats of paint by the manufacturer, who regularly gives a lengthy warranty on the colour and the structural quality.

 

Colorbond Grades

 

How To Prevent Flaking Metal Roof Paint

A good primer is the key to preventing metal roof paint from flaking but also the correct application of it.

The primer shouldn’t be thinned too much or the paint won’t stick. It should also complement the metal type by chemical composition to ensure the tightest possible bond. When the primer is done right, almost any kind of paint will stick to the roof, giving you unparalleled flexibility and durability.

The primer should dry out completely before paint is applied. The manufacturer’s instructions will often explain how to calculate drying time. Once the primer has dried, one coat of paint goes over it, we wait until it dries out and then apply another. That’s the general rule, but again, the instructions on the tin and our own experience are what we follow.

With a metal roof, you should think long term and discuss your maintenance options with a roofer you trust.

 

 

Preventing Metal Roof Flaking

 

AcraTex Primer MX is a water based universal primer for Colorbond® and Zincalume® coated steel in good condition with no rust. – Dulux

Datasheet can be downloaded here.

 

 

Other Factors That Cause Roof Paint To Flake

Plenty of small factors can cause the roof paint to flake within a few months of application. They all come down to the contractor having low or no quality standards.

Humidity/Temperature

Each manufacturer of a roof coating product will specify the humidity and temperature range at which the product works as advertised. The explanation involves a lot of chemistry, but the gist of it is that either being too high or too low disrupts the bonding process.

You don’t have to follow the manufacturer’s recommendations to a T but then you won’t have an even appearance. The final look will be blotchy, though a layperson won’t find anything wrong with it. Worse yet, the product won’t behave as advertised and might cause you trouble later on.

Take a look at Dulux AcraTex 962 Roof Membrane Gloss product specs. It’s an acrylic roof coating designed to be non-toxic and to bind to such a degree that it allows for collection of rainfall as drinking water. However, that’s only guaranteed when applied by professionals who have high standards of quality.

 

 

Flaking Roof Paint - Temperature & Humidity

 

Poor Surface Cleaning

The roof surface can appear clean but still have a thin layer of moss, algae or some other unseen particles that will cause paint flaking. Only a professional roof surface cleaning with power tools can actually dislodge all the particles that will otherwise block the pores in the surface of the roof and lead to paint flaking.

If the roof doesn’t dry out completely after cleaning, that too can cause paint flaking because the moisture keeps expanding beneath the primer and the paint. Our secret to perfectly cleaned roofs is that we have an entire team with heavy-duty tools and experience handling them that works in sync and can sweep across the entire roof with precision and speed.

 

Flaking Roof Paint - Dirty Roof

 

Primer

Choosing the correct primer and applying it the right way means the paint will have a perfectly snug grip on the roof. That layer of primer will seal all the microscopic pores and allow for the paint to fully set in.

Doing it any other way means you don’t actually have a complete seal and there’s a way for moisture to enter between the roof and the paint. Over time, water will work its way beneath the paint and literally lift it off, letting more water in. This is why you will rarely see tiny spots of flaked paint but long strips of it, which shows you the exact path of the water.

It only takes one missed spot where the primer hasn’t been applied correctly for this to become a major issue. Manufacturers know about this problem and do their best to make their roofing materials as versatile as possible, so you have the largest possible choice of primers and paints while retaining a moisture-free seal.

Still, it’s not possible to use all primers with all paints on all roofs. You should have experience using all the possible primer and paint combinations across different roof materials to develop a sharp instinct telling you what works and what doesn’t.

 

 

Nutech Roof Primer

GP Primer is a water-based acrylic, adhesion promoting general-purpose primer designed to improve the bond between a wide range of roof surfaces including smooth, glossy and rough cement roof tiles. – Nutech

Safety Data Sheet can be downloaded here.

 

 

Incorrect Product Choice

Roofs and paints installed in harsh environments, such as near a coastal saltwater spray, most often have a shortened warranty. This is because the corrosion is pronounced and you need to take special care to have a steady maintenance routine. Otherwise, the corrosion will set in, peeling off the paint faster than you can redo it.

Our advice is to look for products that specifically mention the kind of environment your roof is in. If your roof is exposed to salt spray, look for products that are designed to withstand exactly that kind of stress.

For example, there’s Colorbond Ultra Steel, which has been specifically designed for marine environments, and also previously covered in this article.

COLORBOND® Ultra steel has been specifically designed to combine long-term durability and excellent corrosion resistance.  With a metallic coating mass of AM150, COLORBOND® Ultra steel is suitable for severe marine environments.

DIY Job

A flaking roof is also often the result of a bad DIY (do it yourself) job. We understand that it’s exciting to fiddle and tinker with your roof but it’s easy to botch the roof completely while thinking you’ve done a great job. On the surface, the coat of paint might look splendid but that doesn’t guarantee durability in inclement weather, which you won’t know until the roof starts leaking.

You should understand that your roof is a compact whole and can only ever be as strong and durable as its weakest part. Therefore, you should ensure a uniform installation of your roof and an even application of all roof-related maintenance products. That’s best done by calling in a professional team, who will know what to do even in extraordinary circumstances and in crises.

For starters, professional roofers will always abide by the product application recommendations from a roof coating manufacturer, making any roof painting job a no-brainer.

Call Vivify Roofing For All Your Roof Paint Needs

Flaking roof paint is a wakeup call that your roof is one step away from being seriously damaged. Answer the call, pick up the phone and get in touch with Vivify Roofing at 1300 475 097.

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