Flat roof
Flat roof pergolas are quite flexible and relatively easy to build. And yet they are very versatile structures that allow a wide range of customisation that let you customize your outdoor extension according to your needs and preferences. Here are a few things to consider when you decide to build a flat roof pergola.
PITCH
We mentioned earlier that flat roofs are almost level. But flat pergolas should slope a little bit to one side so that water slides off instead of collecting on the roof. We call this angle the “pitch” and we recommend at least a 5-degree pitch.
DEALING WITH HEAT
Flat roof pergolas are easier to build than gable-roofed pergolas, but because of their generally lower profile, they can be extremely warm during the summer. There are a couple of ways you can offset the buildup of heat. You can line the structure with a timber ceiling to provide insulation and you can install fans to enhance ventilation
DURABILITY
Besides protecting you from the sun, your flat roof pergola should also be able to withstand the ravages of wind and weather and survive the harshest climate conditions.
COMPLETE SYSTEM
It’s not enough for water to just run off the roof surface. You need to make sure that the water taken off the roof is properly dealt with. Softwoods flat roof pergolas feature an innovative internal gutter system that works in tandem with Colorbond® gutters, caps and flashings to effectively redirect the excess water from the roof without adding to the load of your home’s stormwater system.
Things To Consider Before Replacing Your Flat Roof
WIND UPLIFT
Your roofing system experiences positive air pressure as wind passes across your roof. This suction effect pulls the roof system away from the structure. If your roofing system is insufficiently anchored when this happens, it could fail. And, if the decking underneath is inadequate; enough uplift can cause substantial structural damage. In the Portland area, typical wind speeds vary from 0 mph to 17 mph, and rarely exceed 26 mph. However, historically, the area has experienced winds in excess of 100 mph.
A flat roof membrane can be attached to the roof deck in two ways; either with mechanical fasteners or be being adhered directly to the insulation or DensDeck cement board, which is then attached to the decking. Each method has its pros and cons. In the case of a mechanically fastened system, the fasteners take the brunt of the pressure and the insulation is largely protected. In the case of a fully adhered membrane, the insulation is put under more pressure.
UL FIRE CLASSIFICATION REQUIREMENTS
Underwriters Laboratories (UL), an independent testing agency, sets standards for fire resistance for all kinds of different products. They give ratings specifically for roofing systems based on their resistance to flame spread. There are three classifications of UL ratings: UL Class A, UL Class B and UL Class C; Class A being the most resistant to flame spread. As a general rule of thumb, and part of many building codes, any publicly occupied building, commercial structure or apartment building must have a UL Class A rated roofing system.
ROOF REPAIR VS. REPLACEMENT
When deciding on a roof system replacement versus just a roof repair, cost is always an important factor. If you think about these expenses in terms of cost-per-year, it can help you make a smart financial decision, but you’ll need to know how long something will last. For example, let’s say a new roof system will cost $50,000 and is expected to last for 30 years. A repair for the same roof will cost $14,000 and the expected life of the repair is 5 years. Not factoring for inflation, the replacement would cost you about $1,700 per year, and the repair would cost you $2,800 per year. While the option requiring the least amount of capital is usually the favored option, cost per year can also influence this kind of decision.
TEAR-OFF VS. ROOF-OVER
Deciding whether or not to tear off an existing roofing system before installing another can be tricky. But, considering the topics discussed above can help you find peace of mind. Some situations can make the decision to tear-off for you, such as water damage, multiple existing roof systems, and extreme structural problems. Others may yield options which do not require the removal of the existing roof system. Just keep in mind that the new roof you install will only be as good as the roof system and structure that it is installed over
Want a flat roof design?
Flat roof designs first gained popularity with arrival of modernist architecture about 100 years ago. Since then they have become common practice for nearly all our large buildings today from innovative hospitals to impressive commercial developments. Traditionally, home owners had the tendency to embrace the familiarity of pitched roofing simply because of the shape of their slopes that lead water away in a practical manner, ensuring less chance for future leaks and liabilities. With changes in technology in recent years, more residents are embracing flat roof homes and are slowly making them a popular choice in both infill homes and new neighborhoods alike.
Flat roof designs present an aesthetic departure from traditional pitched roofs but the choice must be a safe and practical decision and is best made with a little bit of technical knowledge. Here’s a brief overview of the types of flat roofs styles best suited to safely providing coverage over your home and all it contains.
It is important to note that whether you choose a sloped or flat roof, the best roofing system one designed to best practices and constructed by a competent home builder. For your peace of mind, a well built flat roof can outlast three conventional asphalt shingle roofs (commonly installed on most homes) when installed correctly with the right materials. This longevity does come with some added cost as the materials of a well constructed flat roof are of better quality, but when looked at as an investment, you can expect to save on the costs on future maintenance and replacement. Flat roofs are a perfectly practical choice but it still helps to know more about type of flat roof you might choose in building your home.
A true flat roof is just as simple as it states, even and flush but uses sloped systems on top to gently control and direct water to a roof drain or wall scupper that connects to a downspout. In contrast low slope roofs have a much lower slope than traditional roofs and will still lead water off the edge into a gutter and downspout. The pitch of low-slope roofs can vary, but typically they fall between the range of a 2-12 to 3-12 slope. This means for every 2″ in height, the length of the roof will be 12″ long. The higher the first number (ie the 2) the more steep the angle of the roof. However each of these roof types requires a different method of construction to ensure they will perform correctly.
Flat Roofs
For true or ‘real’ flat roofs the best method recognized by most roofing specialists is the Warm Deck System. This system has all it’s insulation and water proof membranes on top of the exterior deck, and exposes the deck to the warmth inside of the building (hence the name ‘warm deck’)
What Goes into Flat Roof Construction?
If you need a low maintenance, affordable roofing system that’s durable enough to last you decades, then flat roof products are the obvious choice. They provide benefits for building in both the residential and commercial sector, but there are things to consider before beginning any flat roof construction. Below are some of the important questions you should ask about a flat roof solution before you begin building.
When is it needed?
For housing purposes, flat roofs can sometimes be an essential bypass if town planners won’t permit the height required for a pitched roof. From an aesthetic point of view, they’re also a highly viable option for ground-floor extensions for multi-storey buildings. Meanwhile for developers and business owners, they’re appropriate as a quick, economic solution for covering commercial buildings. Flat roofing is also useful for waterproofing warehouses or for making public building more flame-resistant among other uses.
What are the main considerations?
What material you should choose – Flat Roofing materials range from fibreglass or bituminous felt options to rubber systems such as EPDM. They each have unique benefits for certain types of construction.
The size of your project – This will obviously affect the amount of material your flat roof will require. In addition, the shape of your building should be considered, as this will affect the amount of trimming needed.
Ensuring that your ‘Flat’ Roof is not ‘Level’ – Flat systems have to ensure water can flow off them, thus which way they are slightly slanted needs to be decided on.
Deciding between a Warm or Cold Flat Roof – Essentially, a warm flat roof is packed with insulation for additional warmth, whereas a cold flat roof allows air to flow between its joists, which can be vented to ensure a continuous air flow. This choice is a factor that should be decided on a case-by-case basis depending on what you want for your project.
Maintenance Concerns – It’s best that someone is able check the roof at least twice a year to clear any debris that, if left, could cause structural damage to your flat roof. In addition, with excessive rainfall, moss can also sometimes be an issue, making maintenance considerations even more important.
Solar Panels on a Flat Roof: Things to Know
Yes, you can successfully have solar panels installed on the flat roof of your home or business. Flat roofs have a minimal slope allowance that will accommodate solar PV panel systems. A roof having a rise of 0.25 inches over a 12-inch run is known as a ¼:12 pitch roof.
These flat roofs are also commonly known as:
Low pitch roofs
Low slope applications
Design and installation challenges of flat roof solar panels encompass the constraints and considerations around valleys and ridges for drainage. To be worth it, consider the positioning and construction of various structures existing on your roof before the design and installation process begins.
You Can Do It!
Carefully considering the choices of flat roof mounting techniques available on the market is imperative. It just takes a bit of research by an expert energy engineer to get you on the right path to solar panel installation on your flat roof.
Your Solar Panels May Or May Not Be Tilted
When installing solar panels on your flat roof, the resulting product can be tilted or not. There are two most pressing factors in the design of a successful solar panel system generating maximum electricity.