Flat roofs are not just for commercial buildings.
Flat roofs are necessary and useful when used to combine roof transitions and limit the roof’s height elevations when they are in conflict with municipal codes. Though these types of flat roofs are much smaller in size when compared to the area coverings of large buildings.
It is important that they be installed with the same proper flat roofing practices as their larger counterparts. If they are treated as a nuisance or quickly applied without proper attention, they will become the weakest link to your entire roof system.
Since the typical materials used for flat roofing offer a far less life expectancy in their basic applications than that of the roofing material used on the rest of your roof, it is important that a thorough discussion take place about your options. If your roof consists of a large flat roof surface, it might be advisable to use some of the more expensive flat roofing materials and systems than the popular materials most commonly used. If you only have a few small flat roof areas, then the commonly used materials are more probable but attention is to be paid at the tie-in transitions. This will allow for easier replacement of these flats when they need replacement and the rest of the roof does not.
The more popular materials used for flat roofing consist of a base-ply membrane nailed to the roof deck. A granulated surface cap sheet is then applied over the base with troweled adhesives, torching or self-adhering adhesives. This type of system typically provides for a twelve year life expectancy. The more plies added under the cap sheet will provide additional life in three year increments. To maximize the life of these roofs, the proper roofing standards are to be practiced. There must be an elimination of “ponding” water, debris buildups and surface wear.
The more expensive flat roofing systems are single-ply weather-resistant materials that are either heat welded at their seams, glued at the seam overlaps or some combination of both to address any detail occurrence. These systems are most commonly highly reflective vinyl or PVC derivatives that provide for a long thirty year life barring any punctures or over stretching of the material. These materials make excellent complete flat roof systems and don't lend themselves to use as small flat roof detailed sections. This is due to the limited roofing contractors that hold certifications for these systems. These roofers are generally large commercial roof contractors but some will seek the residential roof market that provide for smaller roof requirements.
Several of the flat roofing types and materials are as follows:
Built-Up Roofing: This is an old term for the original form of flat roofing. It uses rigid insulation board of tapered foam or Perlite materials. Several plies of fiberglass felts are layered in hot melted asphalt and topped with an additional coat of hot asphalt with embedded gravels or a granulated cap sheet membrane.
Flat Deck Roofing: Flat decks are the flat balconies on a home that show up on the upper storied floors of homes and buildings. They are used for observation enjoyment so because of the foot traffic or furniture placements, they are generally dead level flat. This means that there is little room for error when installing a roof system to provide as the waterproofing surface they will depend on.
Modified Membrane Roofing: These are the new-age materials of flat roofing and ply roofing materials. They are meant to replace the hot asphalt gravel embedded surface treatments of the flat roofs. These membranes weather well and resist the damaging effects of “ponding” water. Because of a multitude of use applications and many acceptable methods of installation, they make good components for most roofing needs.
Thermoplastic Roofing: As mentioned before, these systems are most commonly vinyl materials known as PVC (Polyvinyl Chloride) membranes or TPO (Thermoplastic Olefin) membranes. They are applied by the use of hot air heat welding, chemical bonding with use of solvent adhesives or any combination of the two. These are expensive systems that are meant to last many years in most environments. They are easily repaired by cleaning the surface and heating or chemically bonding a patch in place.
Flat roofs can work well as long as they are able to be kept clean by shedding water and debris buildups as well as any foot traffic being kept to a minimum limiting the chances of punctures.