Clients often ask us about whether their shingle and tile roofs should be sealed.
The first question that should be asked is why someone would want to seal a roof. If there are leaks in the roof and water is penetrating into the structure, then yes – the roof should be repaired by a roofer and made waterproof. This waterproofing typically involves sealing of the underlayment and structure of the roof. This is different from putting a sealant on top of the shingle or tiles themselves.
Whether or not to seal the top surface of the shingle or tile after cleaning is a different question. This is a topic of much debate not only among homeowners but also among the roofing professionals.
There are many different products that are promoted and marketed as roof sealing products. The products promote the benefits of the sealants as providing additional waterproofing, delaying the growth of mold and algae, and protecting the surface color and integrity of the shingle or tile. Often there are more outrageous claims that are made by these products as well.
Many of the purported benefits claimed by the sealant manufacturers do not hold up to be true. There is a lot of marketing and hype on the front end and little data to support the claims in actuality. Some roofing professionals do believe that it is beneficial to seal concrete tile roofs. These are porous surfaces that can absorb water and the color on these tiles will fade over time. Some high quality sealants do provide some additional waterproofing and UV resistance that can help with this. However, the clear sealants that are put on tiles degrade over time and can take on a white or yellow haze that can detract from the beauty of the roof and is very hard to remove when it fails.
Most, if not all, of the roofing professionals that we work with do not promote the sealing of asphalt shingles. Roofs need to breath and allow for airflow. Coatings and sealants interfere with this. Additionally, the shingle manufacturers have been known to void warranties if any sealant or coating has been applied.
Before sealing or coating your roof, it is best to evaluate what it is that you are hoping to achieve, do your homework, and contact a professional before proceeding. There are some high quality sealants available that do provide benefits but can also be costly. Other products can be long on promises, short on results, and can damage your roof.
If you would like to learn whether your roof requires sealing and get a free inspection click here.
Want More Information?