Roof surfaces can either be flat or slanted and in construction, roof pitch is a term used to describe the steepness of a sloped roof. Pitched roofs are the ones that come with two angles that meet in the center as opposed to “skillion” roofs that have a single slanted roof.
There are many reasons why people opt for pitched roofs instead of flat ones, but the biggest one has to be that they come in handy in all weathers. Rain and snow can just slide off of pitched roofs, however, if your roof is flat, you’ll have to find ways of draining the water or snow that gets collected at the top.
This easy runoff allows pitched roofs to have a much longer lifespan than other types of roofs and they are also easier to install. Even people with a very basic knowledge of construction can build and install pitched roofs.
So, if you’re looking to build a pitched roof for your shed, look no further because we can teach you exactly how to do it, with the assistance of a few helping hands.
- What You Need to Know Beforehand
Before you undertake this project, you should make sure that the walls on either side are unequal in their height. This is important to create a slanted roof. If the heights of the two opposing walls are equal, you should try to increase the height of one of the walls by inserting additional plates.
You should also check out building regulations for pitched roofs beforehand. Since flat roofs are susceptible to problems, many people try to convert theirs into pitched roofs. If your aim is to replace or convert your roof, your first task should be eliminating the existing roof. - Scope Out the Location
Pitched roofs require more space on the top so the location of the roof should not be crowded by tree branches or electrical wires. Once you’ve removed all the obstacles from the way, the calculations can begin. - Calculate the Roof Pitch and the Amount of Materials Required
One of the first things you need to determine is your desired pitch, as in how low or steep you want your pitch to be. The ratio for a lower pitch would be 2:12 or 3:12, meaning the roof rises by 2 or 3 inches for every 12 inches horizontally. For a steeper pitch, the ratio will be around 6:12.
Once you have decided what kind of pitch you want and you’ve nailed down the ratio you will be proceeding with, you move on to calculating the number of materials you require. You can calculate this by first determining the area of your roof and consequently the amount of material required.
There are a number of roofing calculator apps available online that can help you with this but if you prefer a manual guide, here is one you can follow to make these calculations yourself. - Plan It Out
After you’ve made the necessary calculations, it’s important to sit down and draw out a plan of the roof, including the measurements, the angles, and the overall layout of the roof. This will help you calculate the spaces you need to leave between the trusses as well as their placements in the roof.
Adding the trusses makes your roof stronger and you can also use extra timber at the intersecting points for more support. This should also be added to your layout drawing so that the work can be carried out with greater precision and accuracy.
You should then proceed to order materials like plywood, underlay, timber, roof coverings, roofing nails, and any other materials you might require. - Start on the Structure
Next, you should begin setting the structure. If the walls are equal and square then you can set up the trusses onto the roof and begin sitting temporary braces on it as well. The first roof truss that you take should be slightly longer than you need and when you set it into place it should jut out slightly. Repeat this on the opposite side and then on the same side again and so on.
You should also create central support that stretches across the length of the building and then join the roof trusses to this centerpiece at regular intervals. Carry on in this manner and the frame should begin to take form. Once it has taken the shape you want, you can start fitting in the permanent bracing and anchor and secure all the trusses. - Add the Sheath
Now that the framework has been completed, the roof is ready to be sheathed. You can make use of plywood sheets for the sheathing and begin from the bottom corner of the frame, moving horizontally across the roof.
Ideally, there should be a small gap between each sheet and the nails should be used 6 inches apart. From the sheet edge, the nail should ideally be only half an inch away.
After finishing the first row, you should move up to begin the second row with half a sheet as it helps to stagger the sheathing. Sheathing should be ended by installing a drip edge along the bottom of every roof edge as it helps to drain the water effectively. - The Underlay
This is the next step after sheathing and drip edges have taken their places in the roof structure. The underlay is also sometimes called the roofing membrane and it acts as a waterproof layer, protecting the structure against all types of water damage by keeping any moisture at bay.
This should be rolled upwards from a bottom corner and there should be an overlap in the drip edge to ensure proper drainage of water. After stapling the first layer in place, the second one should be added with no more than 6 inches in the overlap. - Add the Roofing Material
Finally, roofing materials can now be installed. Tiles, slates, shingles, timber battens, what have you, will be installed at this last stage. We would also recommend adding dry ridge tiles as they protect against harsh weather in addition to being waterproof.
http://www.ultimatehandyman.co.uk/how-to/diy-building/build-a-pitch-roof
https://www.carpentry-tips-and-tricks.com/how-to-build-a-roof.html