Roofing Tips

Avoid These Common Flat Roofing Errors

Despite decades of experience in the design and construction of flat roofs and the use of sophisticated roofing materials, many property owners and managers have doubts and worries about flat roofing errors. The answer to why they worry about flat roofing errors can be found in these factors: Design, Construction and Operation.

Very common flat roofing errors are a result of poor maintenance or a complete lack of it. Regular maintenance requires flat roofs to be periodically inspected for damage, repaired, cleaned, and checked for the functionality of its insulation and waterproofing properties.

Flat Roofing Design

Flat Roofing Design Mistakes

The changing hot and cold seasons deteriorates flat roofing across Southern California every year. On the surface of a flat roof, temperatures can range from +30 to +100 ° F. They are also exposed to UV radiation. Therefore, the nature and properties of the materials from which the flat roofing will be made and insulated with should ensure functionality under these conditions for at least 15-20 years.

Roof leaks, roof moisture and fungus are the most visible consequences of improper or lack of maintenance. Bad insulation promotes heat from escaping through the layers of roofs leading to leaks and flooding from rain. This process becomes detrimental to the flat roof and leads to the deterioration and destruction of the membrane, flashings, gutters, and downspouts.


Thermal Insulation

Each roof type should have carried out calculations of temperature and moisture. The goal is to not only select the correct thickness of thermal insulation, but to eliminate the possibility of condensation between the layers of the roof and eliminate conditions conducive to the growth of mold on the ceiling and walls on the inside. These calculations consider the space around windows, skylights, roof hatchways, etc. These are the places where moisture frequently occurs and are ideal conditions for mold growth. With poor ventilation, steam and moisture within the layers cause separation and can be seen visually on the ceiling and wall in the form of streaks and peeling paint coating, which are signs of weakness in the roof’s waterproof seal.


Regardless of its function, this layer is a must on every flat roof. The most common cause of leaks is contractor error: lack of skilled workers and lack of knowledge of current roofing technologies.

Approaching the problem from the exterior seems to make the most sense to many people. It takes a considerable amount of labor to dig down to the base of your foundation wall. Once excavated, any areas in the roof decking or concrete foundation or walls that have been compromised can be repaired with a new waterproofing membrane.

Substitution of Flat Roofing Materials

A common mistake is to use cheap alternatives or materials other than those provided by the manufacturer or chosen and described in the project documentation. The savings for the difference in material price is usually disproportionate to the cost of any subsequent repairs.

Equipment Technology

Proper execution of waterproofing usually depends on the use of special equipment. The waterproofing layers can be mechanically fastened, glued or welded with hot air, fumes, flame or heat-sealed and require the use of different types of equipment. Overheating of the burner flame can cause weight loss in the asphalt’s insulating properties and can be made “stale”. This risk is virtually removed with the use of insulating materials welded by hot gases or hot air. Welding temperatures in this case are too low to permanently damage the waterproofing material.


Rooftop Equipment

Many property owners believe that the purpose of the roof, because it is flat can be freely changed. Ventilation, HVAC units, tv antennas and other rooftop equipment are connected via an internal installation carried out through the ceiling or attic, through which the lead wires are often randomly located. Each of these elements can have a negative impact on the stability of the roof, insulation and can increase the load.


Roofs with a layer of grass need an appropriate thickness of the substrate. The growing grass requires regular mowing and watering daily. Roofs with vegetation need to be cautiously taken care of. It is unacceptable to hammer into a roof (such as wood or metal supports for trees) without the knowledge and consent of the manufacturer or professional contractor. Waterproofing layers can easily be damaged by this process leading to a re-roof or replacement, which can be expensive.

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