A Modern Look From an Old Idea
Skillion roofs are also known as mono-pitched roofs, a shed roof, or a lean-to roof. They generate the name because they have a single slope mostly seen in sheds. The mono-pitched shelter does not have a ridge in its roofline, resulting in a structure with different wall heights. Architects categorise skillion roof as twisted flat roofs. The result of mono-pitched roofs is clerestory windows, where arrays of windows rise on the edge of the mono-pitched region. One can notice skillion roofs because their pitch is higher than conventional roofs.
Types of Skillion Roofs
There are two types of skillion roof designs. There is the circular style and the butterfly roof style. The circular form, also known as the oval-shaped design, has a curved plan that uses a soft curve for the ridge instead of the typical sharp edge ridge. The circular style is fashionable because of the aesthetic value and its ability to increase the roof’s resistance to wind. The butterfly design combines to skillion roofs which slope towards one point. They are valuable to residents who harvest rainwater because of their effectiveness in trapping the water.
Construction of Skillion Roofs
Flat roofs require the use of an impermeable or waterproof membrane to prevent the seepage of water. The slanting nature of skillion roofs allows them to drain water efficiently, eliminating the use of a layer. Their construction requires good quality metal roofs to enhance durability and aesthetic property.
The primary consideration in the construction of skillion roofs is the leveling and degree of pitch. During the design, wind speeds and storms in Australia should be considered to ensure the angle and the gradients are reasonable enough to prevent destruction. Metal cladding is used on the mono-pitched roofs to achieve the appropriate rises and falls.
Metal cladding is the superior choice due to their lightweight and the ability to make longer spans frequently experienced in skillion roofs. Stick built is the local method of construction of skillion roofs in Australia. In this process, a carpenter cuts and assembles the roof timbers on site.
The sophisticated design of skillion roofs requires the use of a portal frame. The frame contains a series of trusses to provide extra structural support for the overlying roof. Steel or timbers are the standard material used in the construction of the trusses, depending on the level of strength required in the ceiling.
Guttering lean-to roof requires large products to sustain the volume of water harvested from the ceiling. The square box gutters are the favourite designs used due to their size and strength. Other factors to be considered in the construction of skillion roofs are the type of windows and the installation of fascia, eaves, flashing, and barges.
The Benefits of Skillion Roofs
Skillion roofs are easy, fast, and economical to construct. The use of a single slope eliminates the cost of materials required for the construction of the gabled roof. Skillion roofs eliminate drainage problems, typical in other shelter designs. The roof design is aesthetic and useful in any region.
What Does a Skillion Roof Look Like?
A skillion roof—also known as a mono-pitched, or shed-style roof—is a single flat roof that is pitched at an angle. Skillion roofs are distinguishable from regular flat roofs and roofs with a slight incline because the slope on a skillion roof is significant compared to these other styles.
There are many reasons to go with a skillion roof over an alternative style, both from an aesthetic standpoint and an architectural one. However, one of the most significant benefits to a skillion roof is that it is easy to construct. It offers a distinct minimalist appearance and has excellent drainage properties thanks to its steep incline. So, what does a skillion roof look like?
It is a very uncomplicated design in which the roof is flat but sloped. The direction of the slope is largely down to personal preference, though there are plenty of factors that can influence that decision. For example, skillion roofs are popular for homes that are going to have solar panels fitted to them. In those cases, the slope of the roof would face whichever direction that would result in the most sunlight hitting the face of the roof.
The overall look is very modern and helps to get away from the “concrete box” look that some buildings with flat roofs tend to have. In addition to the visual differences, there are inherent advantages when it comes to water management. Water on a skillion roof naturally runs down the slope, whereas water on a flat roof can pool where the roof is not even, which can cause problems in the long run.
Is It Cheaper To Build a Flat Roof or a Skillion Roof?
With any building project, you should always take long term factors into account when deciding on the best plan of action. In the case of skillion vs flat roofing, it may be true that the flat roof will be slightly cheaper to build, but flat roofs have many disadvantages when it comes to things like water drainage. Flat roofs are prone to collecting water and develop problems more quickly than their skillion counterparts.
If you are deciding on the roof for a project—particularly if it is a big project—don’t just compare the upfront cost, research the more common problems of both styles and factor in the price of maintaining and repairing. You will almost certainly find that a skillion roof is more cost-effective over time than a flat roof.
What is a Skillion Roof Going to Cost Me?
In what you will notice is something of a running theme in this post, the cost of a skillion roof largely depends on the project. Skillion roofs can be used on anything from small garden sheds to large retail warehouses, so naturally, the price will vary considerably.
For the garden mentioned above shed, the materials necessary for a skillion roof can be less than $100. At the same time, a large commercial construction will be well into the tens of thousands of dollars. As a rough guide, having a skillion roof built on a typical Australian home will probably fall somewhere between $5,000 and $12,000, though your mileage may vary.
Though it is undoubtedly an expensive proposition (though not as expensive as some alternatives), we would strongly advise you do not attempt to cut any corners in order to save money. A roof—any roof—is a large structure that will be literally hanging over your head, you do not want it to develop problems due to inferior materials or rushed construction.
What is the Minimum Pitch on a Skillion Roof?
Firstly, let’s establish what we mean by pitch. A flat roof is, as the name suggests, flat. If the building were on perfectly level ground, the roof would run parallel to that ground. In contrast, a pitched roof is the more conventional style of roof and essentially looks like a triangle sat on top of the building. A skillion roof is basically a flat roof, but at an angle, sloping down in one direction. It is the angle of this slope relative to the horizontal that we are referring to when talking about the pitch of a skillion roof.
The precise answer to this question can vary depending upon a lot of factors. Is it a primary or secondary roof? Is it a metal roof? The individual circumstances of a build change the ideal pitch of a skillion roof, though there is no universally agreed angle at which a roof becomes a skillion roof.
As a general rule, a skillion roof that is the primary roof on the building should be between pitched at 10 and 15 degrees. If the roof is on a secondary structure—such as a lean-to or an attached garage—the pitch can be closer to 5 degrees.
Other factors come into play when dealing with different roofing materials or very small—or very large—structures, but you should discuss these with a qualified structural engineer or architect before making any decisions based on factors like that.
What is a Skillion Roof Made Of?
The materials used in the construction of a skillion roof can differ from project to project. For a skillion roof on a typical-sized home, the primary material will be wood. The roof will be framed out using large wooden rafters, forming a kind of roof skeleton. From there, the framework will be wrapped in an appropriate membrane such as roofing felt, and finished with a roofing material of choice, such as shingles.
If the building is considerably more substantial, the primary material which the framework is constructed from will likely be switched to strong metal girders. In some smaller cases, such as a garden tool shed, it may not be necessary to have a framework at all, and the panels used for the roof itself will be enough.
Where Can I Get Skillion Roof Plans?
The Internet is always an excellent resource for generic resources; however, it should be noted that using generic plans for a roof will not always yield the best results. You may find yourself spending considerably more on materials than you need to because the plans you use are designed for significantly more strain than your roof will experience. Or worse, you may find your roof is not up to the task because the plans were for something less substantial.
If you are building something small, such as a garden shed or a small garage—especially if the roofing material of choice is relatively light panels—you should be fine using generic plans or even just working it out yourself. If you are building something more significant, such as a house, or workshop, you should have the plans for your skillion roof drawn up for you by a professional structural engineer.
An engineer will factor in many details you may not have considered, such as the typical levels of wind in the area the building will be, and how that will affect the structure. They will also take things like additional load from settled snow in the winter months into account. A good structural engineer will not only be able to make sure your roof is strong enough but will also likely be able to save you money on materials since they will know precisely how strong everything needs to be, and will have much smaller margins of error.
Due to the safety implications of a poorly designed roof, it is always necessary to err on the side of more substantial materials, since a roof that is stronger than it needs to be won’t hurt anyone. It will cost you more to build, though.
Where Can I Find a Skillion Roof Calculator?
In terms of calculating the costs of a skillion roof, there is no calculator that we are aware of. This is due to the hugely variable nature of building a roof. The cost of materials can swing wildly due to seemingly unrelated events in other parts of the world. And the price of labour can also vary considerably due to things like how difficult the building is to get to with equipment. For these reasons, unfortunately, you will have to rely on vague estimates like those we mentioned above when trying to get an idea of cost.
For the design of the roof itself, however, there is a very useful calculator to be found on blocklayer.com. You simply input the requested details of your building, as well as some other information like how much of an overhang you want your roof to have, and it will produce a wealth of useful information. This information includes things like the angle of the pitch, rafter spacing, the surface area of the roof, and much more.