Flat roofing is a necessary aspect of construction industry – something larger buildings could not have been built without. However, flat roofing is an intricate field in construction, and very few roofing contractors can properly specify and install an appropriate roofing material, which would keep the building envelope water-tight, provide energy savings appropriate to building’s geographic location and local climate conditions, as well as being a financially feasible option for roof owner.
A good flat roof must require minimum maintenance, be easily repairable during any season and at any outside temperature, as well as provide long lasting protection from the elements.
Choosing the right flat roofing system is essential for any home or building. Although roof installation on average make only about 3% of total construction costs, roof repairs are among the most expensive services in the construction industry. Consider that if your flat roof leaks, cost of repair will include not only roofing contractor’s labor and material charges, but also the cost of interior repairs, as well as damaged equipment, products inventory, furniture, etc.
Therefore, we recommend that before choosing the flat roof which your roofing contractor is recommending, you do your own research first, and choose the right flat roof for your particular home or building. Keep in mind that roofing contractors may and will recommend roofing products for many different reason: Good price from their supplier, lack of knowledge of the roofing market and different options, habits, etc. Hence, what is best for your roofing contractor, is not always best for you!
Materials for Flat Roofing
There are two distinctly different types of flat roofs: Single-ply roofing and older flat roofs, comprising of sever layers of roofing materials, also commonly known as Built-Up roofs (BUR – a roof that consists mainly of asphalt or tar based products), or a roof that is “built in place”. Each roofing contractor will have their own preference as to which flat roofing systems to use, but in different situation a single-ply roof will be better than BUR, and vise-versa.
Single-ply roofs are newer than various types of built-up roofing systems. Despite the “newer” tag attached to single-ply roofing, you need to understand that most single-plies have been around for more than 40 years, have a proven track record, are easier and safer to install, and often will cost the same or even less than a built-up roof.
There is also a third type of flat roofing systems, which does not fall into either single-ply roofing or built-up roofing category. These are nevertheless very popular flat roofing systems: Spray-Foam Roofing (Polyuria) and Spray-on roofs – Urethane and Acrylic roof coatings.
- Single-ply flat roofing systems:
EPDM Rubber Roofs – oldest single ply roof, and most common roofing system installed today. EPDM rubber roofing is popular due to its relatively low cost and installation methods which do not require any special equipment or machinery. Despite its popularity, rubber roofs are very prone to roof leaks as seam overlaps are glued, and adhesive usually fails within 7-10 years of installation. Once seams begin to fail, rubber roofs require total re-seaming and re-flashing of roof curbs and penetrations.
Also be aware that roofing manufacturers do not generally require roof applicators to be certified and licensed. Therefore there is a great chance that your roofing contractor is not properly trained in installation of EPDM rubber roofing materials.
EPDM has been commercially used for over 40 years and the membrane itself will usually not fail without exterior factors affecting its performance. Most EPDM roof leaks are due to seam failures and installation errors.
PVC Roofing – second oldest single-ply roofing membrane on the US roofing markets. PVC roofing was originally developed in Europe, during massive re-building of post WW II era, when enormous numbers of new multi-family apartment buildings, stores, malls, schools, factories, etc., where built. All these buildings had flat roofs and required a long-lasting solution against roof leaks, which would also be economical and easy to repair in 10, 15 or 20 years.
PVC roofing is a thermoplastic single-ply membrane, and unlike EPDM rubber roofs, the seams and flashing of PVC roofs are hot-air welded, creating a physical bond. Seams of PVC roofs are so strong, that when you try to pull it apart, you will usually tear the membrane, and the seam will remain intact. PVC roofs are naturally Cool Roofs, with white outside surface being the standard color (unlike EPDM rubber’s black surface). Cool Roofs provide tremendous energy savings in southern climates where there is a lot is sun light and HVAC equipment has to work much more than in northern climates, to keep the inside temperature at comfortable level, for building’s occupants.
TPO Roofing – the newest single ply flat roofing material on the US market. Nevertheless, TPO roofing is the fastest growing European TPO roofing. In US, TPO roofs are designed to be as inexpensive as EPDM rubber roofing, yet provide all the benefits of PVC roofing: Hot air welded seams, ease of repair and Cool Roof properties. Despite good intentions and general idea behind TPO roofing, corporate greed of profits-driven roofing manufacturers, turned TPO roofing into potential disaster waiting to happen. Numerous TPO roof failures already accruing on commercial TPO roof installations and future potential roof failures may haunt TPO roofing manufacturers and contractors installing these products for many years.
The nature of TPO roof is to be economical, which requires the manufacturing costs to be as low as possible. What TPO manufacturers decided to do, is to use cheap fillers in manufacturing process, to reduce the cost, as well as make the weathering surface of TPO membrane (top ply, above the scrim – the most expensive part of TPO roof as it requires the components to keep the roof UV stable and to remain pliable) as thin as they realistically could. This and many other factors cased numerous “waves” of TPO roof failures and consequently, major material reformulation, and introduction of at least three new generations of TPO roofing in short 16 years, since introduction of TPO roofing to commercial flat roofing market.
- Built-up roofs:
Built-up roofs – 3, 4 and 5-ply tar or asphalt roof.
Modified Bitumen roofing
Tar & Gravel roofing
Rolled Asphalt roofs
- Spray Roofing:
Spray-Foam roof (insulation)
Acrylic roof coatings
Urethane roof coatings
Typically it’s best to run through flat roof materials with a professional contractor, so that you can get feedback as to what’s going to work best for your price range and roof protection. Through sites like Google.com you can usually find listings for all the local dealers in your area or simply contact TRIO Roofers so that you can get a feel for just what type of roofing is the best for your property.