Roofing insulation benefits | Roof Repair Tips
Building a home is perhaps the biggest investment in the lifetime for most people, and the roof is the biggest contributor to the home cost. Although the focus is on the budget for home construction, few people are aware that the cost can go up many times if the home is not energy efficient. Energy costs can burn holes in your pocket, and to avoid it, you must factor it during home construction by ensuring proper home insulation that makes it energy efficient. With the climate becoming more unpredictable, large parts of the world are experiencing unprecedented heat waves which have devastating effects on the environment as well as the economy. And not surprisingly, the cost of living shoots up drastically due to excessive use of cooling machines that upset the domestic budget and cause immense worries for homeowners.
To survive against the environmental and economic odds that homeowners face, it has become important to pay more attention to building energy-efficient homes or making existing homes more energy efficient. Homeowners must plug all gaps of energy leakage and loss that saves money and helps to improve the environment too by reducing the load of cooling machines. Since the roof receives maximum solar exposure and maximum heat loss happens through the roof, almost 30%, by controlling this aspect, it is possible to achieve considerable improvement in home insulation. And by paying attention to roofing insulation, you can contribute to energy conservation too provided the wall insulation is also up to the mark and complements your effort.
In this article, we will look in more detail about roof insulation in order to discover the role that it plays in the building performance and operations cost. Almost 90% of commercial buildings have a low-slope roof, and insulation remains attached to the deck made of concrete or steel. Typically, the insulation has a part to play in creating a thermal barrier besides providing a working platform and facilitating drainage. To increase the return on investment (ROI) of the roofing Columbus GA, it is important to maximize the role of insulation.
Functions of the Thermal Barrier
Heat movement across the roof happens through three different means – conduction, convection, and radiation. Each type of heat movement impacts the building performance in different ways, and the options of controlling it are different.
Conduction – Heat transfer within solid materials happen by the method of conduction in which the heat passes on from one particle to another within the body of the material. The heat transfer happens almost intuitively.
Convection – The method of heat transfer by convection happens for gases and liquids and is the combined result of heat conduction within liquid or gas and the movement of these substances. For insulation, it translates into heat transfer that occurs within the moisture entrapped in construction materials, through air gaps and negative pressure arising from wind uplift.
Radiation – Radiation can occur in any media – solid, liquid, and gas just as it happens when the roof becomes hot on receiving sunlight or at night when the building radiates heat outside.
Strategies to control heat transfer from the roof by conduction
The first thing to ensure for improving insulation is to increase proper R-value of the primary insulation material. To increase the R-value of the insulation material, the choice of material and the quantity determines the extent of insulation achieved. Next, the target must be to increase the overall R-value of the roof assembly. When all other things are equal, more R-value means more insulation, and since different materials have different R-values, the material type is a contributing factor. The highest thermal value per inch is available from Polyiso, and XPS (extruded polystyrene) and wood fiber have the lowest R-value. You must consider the R-value of each component to increase the overall R-value.
Eliminating thermal shorts or bridging across the components in the roof assembly is another aspect to control heat transfer. Mechanical fasteners cause bridging and can add to the problems of heat transfer. To overcome the problem, use adhesives for fastening and use fasteners that have non-thermal bridging properties.
Controlling heat transfer by convection
Convection happens in gaseous media and air and to control heat transfer on the roof by convection the focus must be on controlling air movement that can happen from gaps in the insulation and even due to membrane uplift by strong winds. Installing air barrier is the solution to the problem, and you must use approved materials like plywood foil-faced Polyiso, cement, and gypsum boards, OSB and fully adhered single plies.
The problem can occur in cold climates too when moisture movement takes place from the humid and warm interior to the cold and dry exterior. Due to the movement, there is condensation under the membrane. In hot climates, the movement takes place from the humid and warm exterior to the cold and dry interior that results in condensation above the deck.
Use of vapor retarder made from a material based on its permeability rating is the solution to the problem. Polyethylene films, single plies, XPS, asphalt felt and EPs or expanded polystyrene all with high permeability rating are suitable for use as a vapor retarder.
Roofing insulation can improve drainage
You can take advantage of the insulation system to improve the drainage system of the roof that plays an important role in increasing the longevity of roofs. In order to divert water away from the curb and walls and direct it to the drains, gutters and other roof outlets you can use tapered insulation boards. You can achieve this very well for new construction and even retrofit it in old buildings. To drain water efficiently, the roof slope must have a gradient of a quarter inch for every 12 inches. However, to meet with the complex needs of roof geometry and to maintain proper slope throughout higher slopes may be necessary.
Protecting the roof insulation system is also very important because it must withstand considerable foot traffic at times when people use it as a working platform. The best way to protect insulation is to use cover boards over it. Installing walkways and choosing an insulation material with adequate compressive strength are the other solutions.