“A cool roof offers numerous advantages over a traditional roof”. A saying that reverberates among most clients and businesses in different countries, especially Pakistan. In urban localities, the heat absorbed by a roof can raise temperatures inside a closed structure, contributing to higher expenditures and lesser comfort. Routine work or productivity also decreases significantly.
According to research, heat-resistant roofs are 50 degrees cooler than a normal roof, the underlying reasons being solar reflectance (surface ability to reflect heat) and emissivity (material effectiveness to emit energy as radiation). To obtain a low interior temperature, the surface should possess a high SRI (solar reflectivity index) and emissivity.
Following are five ways to modify your structure’s rooftop:
- Modified Bitumen
An asphalt-based roofing system that can withstand severe temperatures and environmental elements. With multiple layers of protection, modified bitumen is considered as the best option by millions of individuals.
The layer system commences from ‘Insulation’ which offers the ‘R’ value to help manage heat in different climatic conditions (summers and winters). A stable base is also provided.
Next comes the ‘Modified Base Sheet’. It is used as an anchor sheet for hot welded or cold adhesive roof assemblies. The sheet is made from two types of polymers:
- SBS (styrene-butadiene-styrene)
- APP (atactic polypropylene)
Modified bitumen membranes are used in commercial sectors, including warehouses, hospitals, cafes, and more. It can withstand low and high temperatures because of its characteristics. Moreover, additional layers of sheets can be used too.
An adhesive is a waterproofing material applied hot or cold. It creates a strong bond with SBS modified membrane and other asphalt roofing sheets. The bonding agent offers low temperature flexibility and lap strength adhesion.
The last layer is called ‘Surfacing’. It has white granules that create a strong reflective coating. Moreover, the sheet offers weathering resistance and UV protection.
- Single-Ply Membrane
Single-ply membranes are considered as one of the most popular roofing materials. It comprises flexible sheets of synthetic polymer divided into two groups: thermoplastics and synthetic rubber. There are several types of single ply membranes:
- Polyvinyl Chloride (PVC)
PVC is simple to manufacture and install. Due to its long-lasting characteristics, it can withstand toxic chemicals and slurries. It is available in different colors; users can opt for a matching fit! This membrane cannot be used with bitumen roofing without a dividing layer.
- EPDM Roofing
EPDM is an elastic rubber roofing membrane. It is commonly used in local projects, such as residential and commercial housing. It is composed of two ingredients: ethylene and propylene. It is installed as fully adhered or mechanically attached with special tape or liquid solvents.
Other single-ply membranes include:
- TPO (Thermoplastic Olefin) Membrane Roofing
- TPE (Thermoplastic Polyolefin Elastomer)
- PIB (Polyiso Butylene)
- Ballasted Roofing System
Ballasted Roofing System consists of a membrane placed on the rooftop and stabilized by the weight of concrete pavers or stones; the stones provide an isolating barrier against solar radiation. The method is inexpensive and energy-efficient.
Some benefits of a ballasted roofing system are:
- Easy installation
- Comfortable in use
- Green Roofs
A green rooftop is a vegetative layer with varying levels of materials. It shades the building from the Sun’s rays and reduce surface and air temperatures through different processes, such as transpiration and evaporation. According to EPA, green tops can reduce temperatures by 30-40 degrees Fahrenheit. In other words, these roofs can lessen the impact of ‘Heat Islands’.
There are two types of green roofs:
- Extensive Green Tops
- Intensive Green Tops
Extensive Green Tops
This roof requires the least amount of structural support because of its lightweight property. In addition, it needs low levels of maintenance. Intensive green roofs have a moderate depth of 2-4 inches.
Intensive Green Tops
This roof top requires more structural support and maintenance because of increased plantation. Compared to its counterpart, intensive green tops need a higher investment. The dense vegetation provides a distinctive view of a park with trees.
- Metal Roofs
A genuine metal roof can last for 40 to 70 years. Thanks to its durability, the user can enjoy a comfortable and safe environment. A metallic roof can withstand winds up to 140 miles/hour. In addition, it is rust-resistant and reflective.
Other benefits include:
- 10-25% reduction in cooling costs
- Low weight
Having a cool roof is necessary for residents of Pakistan, especially Karachi. Because of hot summers and warm winters, the metropolis faces severe heat-related issues. To manage the rising costs, individuals need to refurbish the roof with coatings or materials.
It’s best to consult experts like Waterproofing.pk for an informed decision.