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Shifting to Flat Roofing System

Admin May 19, 2022

Flat Roofs are more common in commercial buildings where they need much space for the equipment to supply their structure than in residential homes. Whether you are building your new home or upgrading your roof, you have a lot of choices from styles, sizes, and either a sloped or flat roof. And if you are opting for flat roofs, this one's for you!

Components of a Flat Roof

1. Roof Decking

This is where your flat roof rests. It can be made of planks, boards, or plywood.

2. Vapor Barrier

This layer is to protect your roof from any moisture, this helps your interior dry and without leaks.

3. Insulation

Insulation is your protection from the heat transfer from the sunray, this helps reduce the heat felt inside your building or home.

4. Waterproofing

Waterproofing your flat roof is to avoid leaking from the thermal cracks on your roof. There are many ways of waterproofing your flat roofs which the most common are: waterproofing sheets or polyurethane waterproofing systems.

Different types of Flat Roofs

1. Built-Up Roofing (BUR) System

Built-Up Roofing System is the oldest flat roofing system. This type of flat roof is made from layers of asphalt and bitumen and combined with roofing felts. The process of the built-up roofing system is the application of hot tar or asphalt blended with bitumen which is being reinforced with roof felts. This process will be repeated on top of each layer for two to four piles until desired thickness is achieved. Now with the advancement, roof felts are usually made with fibers or organic mats.

Due to added layers in the process of the Built-Up Roofing System, it is greatly resistant to thermal expansion/contraction and vibration.

2. Modified Bitumen System

The Modified Bitumen System uses a new type of bitumen that is modified to increase flexibility and reinforced for added durability. The modifiers that are used are atactic polypropylene and styrene butadiene styrene which are types of polymers. To increase the strength or durability, polyester mat or fiberglass are being added. The process of applying a modified bitumen system sometimes depends on the modifier being used. It can be hot-mopped or torch down.

3. Single Layer Membrane Roof

Single Layer/ Ply Membrane Roofs are prefabricated sheets that are easier to install. This flat roof system is made of synthetic rubber or polymer which is elastic, flexible, and durable. And since these are manufactured, it follows a quality control to achieve consistency of the material. The two most common single-layer membranes are Thermoset Membranes and Thermoplastic Membranes.

Thermoset Membranes are made from rubber polymers, formed as sheets, and installed in a single layer. Thermosets, from the word itself, sets when applied with heat. This can withstand harsh heat conditions. Some common thermosets are ethylene propylene diene monomer (EPDM) and CSPE. Installation of thermoset membranes should not be by welded but by the use of adhesive, mechanical fasteners, or tapes.

Thermoplastic Membranes are made from polymers that soften when heated and harden when cooled. Some common thermoplastics are thermoplastic polyolefin (TPO) and polyvinyl chloride (PVC). Installation of thermoset membranes can be by heat welding or it can also be mechanically attached.