Rawlins Paints Blog Industrial Paint Tips, Guidelines & DIY Articles
Wondering “how long does gloss take to dry”?
There’s nothing more frustrating than spending time and effort on a painting project only to find that the paint just isn’t drying as it should. You touch the surface hours after applying the final coat, expecting it to be dry and smooth, but instead, it’s still tacky or smeared. Often, the reason is simple yet often overlooked: it’s too cold. This is an issue that affects exterior painting projects over winter – cladding, uPVC doors and windows, masonry – when the mercury drops.
The Chemistry of Paint Drying: Why Temperature Matters
To understand why cold weather can wreak havoc on your painting project, it’s important to grasp the basics of how paint dries. Paint doesn’t just dry by losing moisture; it cures through a chemical process that transforms it from a liquid into a solid. This process, known as polymerization, is highly dependent on the right conditions – temperature being one of the most critical.
When temperatures are too low, the molecular reactions that enable paint to harden and adhere to a surface slow down significantly. In some cases, the paint may never fully cure, leaving a soft, sticky surface that’s prone to damage. This is why manufacturers always specify a minimum temperature range for their products. Ignoring this guideline can lead to a range of problems, from an uneven finish to outright paint failure.
Why Cold Weather Is a Paint’s Worst Enemy
Attempting to paint on a cold day may seem like a good idea at first. The sun might be shining, and the air might feel crisp and clear. However, appearances can be deceiving. When the temperature drops below the recommended level – often around 10°C for most paints – the problems begin.
Thickening and Uneven Application
One of the first issues you’ll notice is that the paint becomes thicker and more difficult to spread. This is because the cold causes the paint’s viscosity to increase, making it harder to apply smoothly. You might find yourself working harder to cover the surface, only to end up with a streaky, uneven coat.
Slowed Evaporation
For water-based paints, the evaporation of water is a crucial part of the drying process. Cold air can hold less moisture than warm air, meaning that as temperatures drop, the rate of evaporation decreases. This leads to extended drying times and can trap moisture within the paint, preventing it from curing properly. The result is a surface that remains tacky for an extended period, sometimes days or even weeks.
Poor Adhesion
When paint is applied in cold conditions, it may not bond effectively with the surface, leading to poor adhesion. This can cause the paint to peel, crack, or blister as it dries. Imagine spending hours painting only to have your hard work start peeling away within days.
Condensation and Moisture Issues
Cold temperatures often bring increased humidity or dew, especially during the early morning or late afternoon. If moisture settles on the surface before the paint has dried, it can lead to a host of problems, including bubbling, blistering, or even complete paint failure. The presence of moisture can also prevent paint from adhering to the surface in the first place, making your efforts futile.
The Importance of Following Manufacturer Guidelines
Every can of paint comes with specific instructions regarding the ideal temperature range for application. This information isn’t just a recommendation; it’s a critical guideline that should be adhered to if you want your paint job to last. These guidelines are based on extensive testing by the manufacturer to ensure the paint performs as expected under the right conditions.
For example, if a paint manufacturer states that the product should be applied when temperatures are between 10°C and 29°C, it’s crucial to stay within that range. Painting outside of these conditions can result in all the issues mentioned above, leading to more time and money spent on repairs and reapplications.
Why You Should Always Check the Weather Before Painting
Before starting any painting project, it’s essential to take a few moments to check the weather forecast. Look beyond just the current temperature; consider the forecast for the entire day and the next few days as well. You want to ensure that the temperature will remain within the safe range for at least 24 hours after application. This ensures that the paint has enough time to dry and cure properly.
Additionally, investing in a simple surface thermometer can be incredibly useful. While the air temperature might be acceptable, the surface you’re painting could be much colder, especially if it’s in the shade or exposed to wind. Measuring the actual surface temperature can help you make more informed decisions and avoid common pitfalls.
Rawlins’ Recommendations for Cold Weather Painting
When it comes to painting in cold weather, Rawlins’ technical paint experts offer some crucial advice: opt for solvent-based paints over water-based ones. Here’s why this recommendation is so important.
Solvent-Based Paints vs. Water-Based Paints in Cold Conditions
Solvent-based paints are generally more resilient in colder temperatures because they rely on a different drying process than water-based paints. Solvent-based paints dry through a process of oxidation, which is less dependent on temperature. This means that even in cooler conditions, solvent-based paints can still dry and cure effectively.
On the other hand, water-based paints rely on the evaporation of water to dry. In cold weather, this evaporation process is severely slowed, leading to prolonged drying times and an increased risk of the paint never curing properly. This can result in a tacky finish that remains vulnerable to smudges and damage long after application.
Some of the more popular solvent-based paints for winter use at Rawlins Paints include:
Zinsser Allcoat (Solvent Based)
Specialist multi-surface coating in satin or gloss for temperatures as low as 5°C – ideal for winter work on uPVC, timber, metal, masonry, plastic, concrete, cladding and more.
Zinsser AllWeather Exterior Masonry Paint (Solvent Based)
Rapid protection against showers in just 20 minutes. For winter use on masonry surfaces including brick, concrete and stone, down to -5°C.
Both products are available in 4,400+ colours (including anthracite Grey) for matching existing shades or for rebranding with a stylish modern look.
The Benefits of Solvent-Based Paints in Cold Weather:
Faster Drying Times
Solvent-based paints are less affected by cold temperatures, allowing for quicker drying times even when the mercury dips.
Better Adhesion
These paints adhere better in cold conditions, reducing the risk of peeling or flaking.
Durability
Solvent-based paints often provide a more durable finish in cold weather, ensuring your paint job lasts longer.
Avoiding Paint Problems in Cold Weather
The best way to avoid issues with painting in cold weather is simple: don’t do it. If you can, wait for a warmer day when conditions are more favourable. However, if you must paint in cold weather, here are some tips to help ensure a successful project:
Use Solvent-Based Paints
As recommended by Rawlins, solvent-based paints are your best bet in cold weather. They’re more reliable in low temperatures and less prone to the issues that plague water-based paints.
Check the Forecast
Always review the weather forecast before you start. Ensure that the temperature will stay within the recommended range for at least 24 hours after application.
Monitor Surface Temperatures
Use a thermometer to check the actual surface temperature before you begin. This is especially important for exterior projects where surfaces can be significantly cooler than the surrounding air.
Paint During the Warmest Part of the Day
If you’re working on an exterior project, aim to paint during the warmest part of the day, typically between late morning and early afternoon. This maximises the chances of the paint drying properly.
Avoid Condensation
Be mindful of moisture. Avoid painting when there’s a chance of dew or frost, which can interfere with the drying process and lead to bubbling or peeling.
Consider Thinning the Paint
If the paint is too thick due to the cold, consider thinning it slightly according to the manufacturer’s recommendations. This can help with application and improve the overall finish.
Wait for the Right Conditions
If the weather isn’t ideal, it’s often better to wait. Postponing your project until the temperature is more favourable can save you from the hassle of dealing with a botched paint job.
Why Cold Weather Paint Problems Are Avoidable
Cold weather can make painting a challenge, but with the right preparation and products, it’s possible to achieve a quality finish. By adhering to temperature guidelines, using the right type of paint, and carefully monitoring conditions, you can avoid the common pitfalls that lead to prolonged drying times, poor adhesion, and other issues.
Remember, the goal is to ensure that the paint cures correctly. This means giving it the right environment to bond with the surface and harden into a durable, long-lasting finish. While it might be tempting to rush into a painting project regardless of the weather, taking the time to ensure conditions are right will pay off in the long run.
FAQs
Why does cold weather affect oil-based paints differently from water-based paints?
Oil-based paints dry through a process called oxidation, where the oil reacts with oxygen to form a solid layer. This process can continue at lower temperatures, although more slowly, whereas water-based paints rely on evaporation, which cold weather significantly slows down.
What impact does wind have on drying paint in cold weather?
Wind can cause the surface of the paint to dry too quickly while trapping moisture beneath, which leads to issues such as blistering or peeling when the underlying layers fail to cure properly.
Can additives help paint dry in cold weather?
Some manufacturers offer paint additives that can be mixed with water-based paints to enhance drying time in cooler conditions. These products help to reduce surface tension and improve film formation, but results may vary depending on the specific paint and environmental conditions.
How do temperature fluctuations during the day affect paint drying?
If temperatures fluctuate, especially dropping significantly at night, this can interrupt the curing process. The paint may seem dry but remain vulnerable to damage or moisture absorption, causing problems later on like cracking or loss of adhesion.
Why is the surface material important when painting in cold weather?
Different materials retain heat at different rates. Metal and stone surfaces tend to cool faster than wood or drywall, which can make them more prone to condensation or slower drying times, even if the air temperature is suitable for painting.