Best Time Of Year To Coat My Roof?

One of the most common questions asked of roof coating contractors in Tucson is, “When is the best time of year to coat my roof?” Many worry about the monsoons causing leaks which lead to a need for roof repairs but they are also concerned the Tucson heat is too much for elastomeric roof coatings. Roof coating experts understand the concerns homeowners have and definitely take these into consideration.  So what is the answer? The answer is simple: Roofs can be coated any month of the year in the Tucson and Green Valley and surrounding areas with some caveats.

Caveat #1: Never Coat A Wet or Damp Roof

There is very little rain in Tucson so that is definitely a plus when considering when to coat your roof. The Tucson area only receives average 10-12 inches or less rain per year.  Most days are rain free which means that the roofs are usually dry. In the winter, the dew point can cause moisture on the roof in the mornings but usually by mid-day they are dry and ready for roof coating to be applied.  All good roof contractors know to never apply roof coating when the roof is wet or damp. If a roof has numerous half-circle blisters in the coating, this is because somebody coated it when it was damp or wet.  Blisters can be prepared, but moisture is what causes them.

Caveat #2: Don’t Coat a Roof When it is Too Hot

If you are considering what is the best time of the year to coat your roof the heat is a serious concern. What’s too hot?  Hot is a relative term when considering roof coatings.  When the ambient temperature is above 100 degrees Fahrenheit, the roof surface can be much hotter.  When the roof’s surface gets above 100 the coating will dry very quick and there are usually no drawbacks for the coating so long as it is properly applied.  However, if the roof is too hot the rollers tend to stick to the roof as the coating is being applied. This may keep the coating from properly laying down. It can also lead the roof coating specialist to apply the coating either too thin or too thick.  If the roller is sticking, it is too hot to roll on coating.  Some roofers like to spray the coating. When the temperature is above 100, spray pumps can clog and this too can cause problems.  In the summer, most roof coating companies near you will likely start early when the temperatures are lower and could possibly return in the afternoon when the temps cool down.  A general rule Desert Sky Roofing adheres to is that when the temperature gets above 100-105 degrees, we start shutting down rolling operations. 

Caveat #3: Don’t Coat A Roof When Extreme Weather Is Expected

This caveat applies primarily to storms, cold fronts, and other major weather phenomena.  In the Tucson area and even in the south of Tucson near Green Valley storms can arise rapidly. With the storms come extreme temperature changes.  In the summer, roof coatings dry very quick – usually within one to two hours. However, in the cooler months it may take 2-4 hours for the coatings to dry.  If a roof is coated in the late evening during the cooler months and the temperatures are dropping significantly in the afternoon the roof coating may need much longer than just a few hours to dry. Unfortunately, in those situations the mornings often deliver dew to the roof tops. If dew falls on the roof and the roof coating has not dried enough the coating will leach its surfactants. This is when the soaps (or binders) in the coating come to the top. They eventually dry off, but if the dew is heavy enough water can drip off the roof and this water will have white or tan tint from the roof coating. It is always best in the cooler months to watch the dew points and try to finish coating roofs in a manner that allows them ample time to dry.  One of the ways roof coating contractors beat this in the winter is by using winter grade coatings that are created to dry fast.

Caveat #4: In Cold Weather Take Caution

Most elastomeric cool coatings can be applied when it is above freezing but it is best when the temperature is above 50 degrees. Tucson Rubberized Coatings recommends the temperature of their 7000 product be applied above 55 degrees Fahrenheit. Lucky for us in Tucson, it is almost always above 55! Keep mind mind that that the air temperature and the roof temperature are two different considerations. When the sun shines on the roof coating it heats up quickly. It can be 45 degrees in the air and the roof itself can be 55 degrees. The key is to make sure the temperature is rising when working in cooler temps because it is important that the coating have enough time to dry before the temps start to decline.

These are just a few guidelines on when and when not to coat your roof.  All good roof coating companies will know when it is ok to put down roof coating. If you have any questions about your roof give Desert Sky Roofing a call or send us an email and we can set up a time for a free inspection of your roof.  520-444-5218.