Does Thermoshield Paint Work – Should I Paint my RV’s Roof

Word has been circulating in Australia about the superb performance of Thermoshield paint on roofs, particularly motorhome and caravan roofs. Still, is it actually worth the effort of you rushing out to buy and painting your RV? Obviously, you should consider weighing up the pros and cons.


What makes paint work on vehicle roofs?

The main purpose of paint is to prevent a surface from degrading. And for vehicle roofs, the most important harm to watch out for is heat and rust. But there are also other essential things to consider such as safe ingredients and dry weight. Based on such factors, it’s safe to say that Thermoshield works as a “complete solution” vehicle roof paint but with a few consequences.


What is Thermoshield and how does it work?

Most likely RVers are aware of only the Thermoshield Roof Insulation Coating, so let me clarify things a tad bit better for you. For badly damaged surfaces including RV roofs, Thermoshield offers five treatment stages where steps 2 to 5 use different Thermoshield products. By the way, by “badly damaged” I mean “badly rusted and with holes, cracks and leaks“. Specifically, Thermoshield’s complete solution scheme goes:

1. Surface preparation Just like before any paint application, Thermoshield prepares the surface so that it would be in a condition where:

  • There is minimum hindrance (e.g. rust, debris, etc.) to the effectivity of the succeeding treatments to be done
  • The surface can readily accept the products to be applied to it – no flaking, peeling off or similar occurrences

In specific terms, they clean the surface with soap and water, power wash or scrub as applicable. Also, initial repairs are done at this stage.

2. Rust treatment Thermoshield applies its Rust Converter product only to the badly rusted areas. What such product does is it converts all ferrous oxides (rust) into phosphates. This is an irreversible reaction – meaning, the phosphates can’t turn back into rust.
3. Primer coating Thermoshield applies a Primer Coating to protect the rust-treated areas plus cover other areas for uniformity.
4. Waterproofing Depending on how large the holes and cracks are, Thermoshield waterproofs them by applying either or a combination of these:

  • Silicone seal
  • Expandable foam
  • Thermoshield Ceramic Membrane Sheet
  • Other sealing media
5. Top coating To enclose all prior treatments while insulating the entire surface, Thermoshield applies its Roof Insulation Coating.


So if your RV roof and/or walls are still in good condition, you may use just the Thermoshield Roof Insulation Coating which will be our point of interest for the rest of this post.


The Thermoshield technology

Thermoshield’s roof insulation coating is made of fine, vacuumed ceramic particles. And because they’re vacuumed, these particles totally do not allow air-carried heat and moisture from entering your RV. Hence, the term “insulation coating” instead of your typical “paint“.


The benefits of Thermoshield paint

Thermoshield TC 938/45S/101 highlights its heat reflective ability, making your RV/caravan interior cooler. As a result, you’ll be saving a lot in power expenses especially during summer or day trips. Additionally, this Thermoshield Roof Insulation Coating offers these advantages:

  • Non-Toxic (since it is water-based)
  • Abrasion Resistant
  • Mildew Resistant
  • Cleanability – it can be easily cleaned using only soap and water
  • Waterproof
  • Australia-specific – it is formulated to suit the Australian climate conditions

Now those are benefits you can hardly find all in one paint. Not to mention, Thermoshield has Australia-specific certifications which is something that’s not highlighted as much on global paint brands.


The approach to evaluating Thermoshield

So to see how Thermoshield’s properties fare against other automotive paint, the most viable path would be to obtain their datasheets. And to obtain a wider range of observations, I picked out two types of automotive paint from a common brand. The first is a solvent-based refinish paint while the second is a water-based basecoat paint.

Even so, I can’t say that the technical comparison below is complete. It would be better if actual costs and test experiments were included. While researching this article we could find no evidence of heat-reflective data of regular automotive paints publicly available, so we can not provide any feedback on their products.


Technical comparison at a glance

PARAMETER THERMOSHIELD PPG (solvent-based) PPG (water-based)
Product Name/Code TC 938/45S/101 Deltron BC Group 1 Mixed Colour (452-00001/20L) White Envirobase (T400/2L)
  • Acrylic polymer emulsion (30-60%)
  • Titanium dioxide (10-30%)
  • Inorganic extender (10-30%)
  • Water (10-30%)
  • n-butyl acetate (30-60%)
  • methyethyl acetates (<20%)
  • xylene & ethylbenzene (<20%)
  • butan-1-ol (<10%)
  • 2-butoxyethanol (<10%)
  • 2-(2-butoxyethoxy)ethanol (<10%)
Hazard Classification Not hazardous as per Safe Work Australia
  • Flammable liquids – category 3
  • Skin corrosion/irritation – Category 2
  • Serious eye damage/eye irritation – Category 1
  • Specific target organ toxicity – single exposure (narcotic effects) – category 3
Not classified
Hazard Statements N/A
  • Flammable liquid and vapour
  • Causes skin irritation
  • Causes serious eye damage
  • May cause drowsiness or dizziness
No known significant effects or critical hazards
State Viscous liquid Liquid Liquid
Flash point N/A Closed cup: 26°C Closed cup: 93.33°C
Density 1-1.2 (specific) 0.97 (relative) 1.23 (relative)
Boiling point (°C) approx. 100 128 >37.78
Stability & reactivity
  • Stable;
  • Thermal decomposition may produce acrylic monomers, carbon monoxide, carbon dioxide and oxides of nitrogen.

No reactivity data available


No reactivity data available


Handling & Storage Store in a cool, dry place.

Do not allow to freeze.

5 to 35 °C

Do not store near oxidising agents, strong alkalis & strong acids

Acute Toxicity Estimate 150ppm vapour inhalation 172.8ppm vapour inhalation
No. of coats At least 2 2 to 3 medium wet coats + 1 light control coat for metallics 2 to 3 coverage coats + 1 control coat
Drying time 15 minutes 15-20 minutes ave.
Film build 500 micron total wet film 10-25 micron (dry) 12 micron (dry)
Coverage 2 m²/L for two coats 3.5-7 m²/L 8-19.3 m²/L

“-“ means “no data available”


Critical Observation: Ingredients

Thermoshield’s water-based nature confirms its eco-friendly effect. This is reflected in its other properties such as flash point, storage conditions and hazard classification.

Solvent-based automotive paints have ambient temperature flash points. In other words, they produce flammable vapour when left exposed even at normal temperatures. And since some parts of Australia can reach over 40°C in summer, so Thermoshield get s a plus point for this.

The ultimate effect is that solvent-based paints have more hazard descriptions which you do not want.

Now comparing Thermoshield and Envirobase, you can see that they have different ingredients though they’re both water-based. Let’s see in our next analysis how this affects their other properties.


Critical Observation: Application

The application conditions of the three products say a lot about cost and weight. Thermoshield seems to cover a much smaller area compared to other automotive paints. Therefore, you’ll generally consume more Thermoshield paint than PPG paint.

The case is the same with their weights. When completely applied, Thermoshield accumulates a thickness of 500 microns (wet) while only 50.8 microns (dry) for Envirobase. (That is, 12.7 microns x 4 coats maximum). You can already see the difference in weight. Let’s say the surface area of your RV roof is 15m². If you paint it with Thermoshield:

Formula for Thermoshield coverage

Since Thermoshield has 50% volatiles and 30% water as per their MSDS, the dry weight would be about 1.8kg. If we compare it to the other two,

other paints mass formula


So you can see. Thermoshield’s estimated dry weight is generally greater than that of regular automotive paints, whether solvent-based or water-based. While this is not a big deal for larger vehicles. It could be something that needs to be considered if you’ve got a small RV where every kilogram counts. Or a caravan with a light ATM and you have been guilty of overloading it as it is. After all, having heavy paint leaves you a small allowance to put stuff in your vehicle.



Note that the above analyses are based only on data publicly available (i.e. on their websites). So I take no responsibility for any loss of information as a result of not having undisclosed data.


To buy or not to buy?

Given its numerous benefits, Thermoshield is definitely good to have. Even so, it does not mean that you immediately have to run to the shop and buy. Consider first if you really need and want it.


Has your current vehicle roof been spent?

If your roof paint has already served its life, why not consider repainting it with Thermoshield? If there is surface rust starting to appear, then maybe it’s worth applying Thermoshield to stop this in its tracks.


Do you often use your vehicle in the summer?

If you’re travelling or spending time inside your RV during the daytime in summer, then you can maximise the benefits of Thermoshield. This is where you will get the most benefit the product from – even more when you practically live in your own RV!


Does your wallet allow it?

Of course, the Thermoshield benefits do not come without cost. Given our Application analysis, you can quite estimate how much more you need to shell out.


Are you willing to make the effort?

This is assuming that you’ll be the one doing the painting job. You will have to prep your roof, making sure the surface is clean and even. After that, you’re going to apply the coat and wait a certain time to dry. Then repeat these until you achieve the required number of coats. All these while getting fried up in the Australian heat.

To top it all, note that Thermoshield has a small coverage which will require you to paint for a longer time. So are you willing to go the extra mile?


Is Thermoshield the only option?

No. In fact, there is a paint called Super Therm® which offers benefits that are very similar to that of Thermoshield. I made a separate comparison on Thermoshield vs Super Therm®, which you definitely would want to check out because the results are interesting.

Another option is using primers or topcoats that offer the same benefits that one Thermoshield paint offers. This is actually the usual path. Costs, however, require an entirely separate discussion.


My take on the matter

In summary, Thermoshield takes the trophy for its numerous benefits, eco-friendliness, and low operational costs. On the other hand, it’s highly likely to be costly, covers only a small area, and is heavy. That being said, Thermoshield is indeed good to have but not necessarily an immediate requirement.

If your vehicle is fairly new or you don’t frequently drive under the sun – would you really need it? If so, have you considered other options – may be a clear coat that has excellent heat protection ability and better coverage? But in the end, if your budget calls for it then why not?


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