Since the 1970’s, the preferred roofing products for waterproofing light-weight and low-sloped roofs have been manufactured in industrialized countries with modified bitumen membranes.
Here in Costa Rica, there are many commercial buildings and casas with light-weight roof structures, covered with thin metal laminates, and most of these roofs leak, because of the number of screw holes made to attach the laminates, as well as low-quality flashing installations.
However, most foreigners that relocate here, are not accustomed to these cheap and leaky roofs, and many folks search for a roof waterproofing solution for the houses they purchase here.
For this reason, years ago, I began to receive requests from clients to provide a roof waterproofing solution that could be installed on the light-weight metal roofs.
Since Costa Rica is not an industrialized country, and there are few manufacturing facilities capable of producing waterproofing products here, I needed to source suitable products from other countries, and import them here.
The best products are manufactured by modifying bitumen and asphalt with rubber and plastic, to provide waterproofing qualities, as well as protection from exposure to the intense sun and UV radiation here, since Costa Rica is located only 12 degrees north of the equator.
Since light-weight roof structures are made from materials that tend to move with seismic activity, and they expand and contract from extreme heat, it is important for waterproof roofing systems to be flexible in order to tolerate these movements.
I found that modified bitumen roofing products are the preferred solution of many professional roofing and waterproofing contractors around the world, because they are manufactured in controlled environments, with modified bitumen sheets that are consistent in quality and thickness, and they tolerate extremely high temperatures.
Now let me explain the qualities of the two most widely used types of modified bitumen roofing products here in Costa Rica.
SBS – styrene-butadiene-styrene; is modified bitumen processed with synthetic rubber, which results in an excellent abrasion resistant product that adapts well to underlying structures, like the thin metal laminates found here. Because it is flexible, it can better withstand high winds and temperature fluctuations. The disadvantage of SBS is that it does not provide the best protection for the roof surface from exposure to the sun and UV radiation.
APP – atactic polypropylene; is modified bitumen processed with elastic-plastic, making it flexible at ambient temperatures, and more thermal resistant to the sun and UV radiation than SBS. Additionally, APP has a high-temperature tolerance when being heated during installation, so it is more user-friendly for installers, making it more cost-effective.
Over the years, I have installed both SBS and APP waterproofing membranes on my clients roofs throughout Costa Rica, and the installations continue to provide the homeowners with the confidence that the interior of their homes are protected from moisture infiltration as well as from the intense sun and UV radiation that all of us experience here in Costa Rica.
The writer, Tom Rosenberger has lived and worked in Costa Rica since 1992 and from his travels throughout the country inspecting the construction of housing, he has acquired a wealth of knowledge about roofing here. If you would like to schedule a roof inspection, you can contact Tom by clicking here.