A detailed do it yourself guide for your outdoor roofing project
Hi i’m Richard and I’ll start by showing you a step by step guide on how to install a outdoor gazebo roof with asphalt shingles. The same installation technique can be applied to a garden gazebo, patio, pergola, shed, garage or even your home. When we send out this comes in an outdoor gazebo kit with all of the necessary roof materials ready to use.
We need to take a few measurements to calculate the materials needed for the job. Generally asphalt shingles come in bundles of 21 pieces which cover 3m².
- You will need to calculate the total area of the roof.
- You will need to calculate the total length around the bottom edge.
- You will need to measure the combined total length of the hips and ridge.
Calculation number 1 will determine how many sheets of plywood you will need. A standard sheet of plywood is 2400mm x 1200mm. One of these sheets is equal to 2.88m². Generally you can work with about 10% wastage. It will also show how much asphalt impregnated roof felt you will need – Add 10% for wastage. (more on roofing felt later). It will also give you part of your asphalt shingle requirements. Calculation number 2 will show you how many metres of starter course and metal drip edge you will need – each bundle of asphalt tiles has 21 lineal metres of starter course. (I will go into detail later). Calculation number 3 will tell you how many bundles of asphalt tiles you will need for the hips. Each bundle of asphalt tiles covers 8.8 lineal metres of hips (or ridge).
TIP “The plywood used is 12mm Structural A-bond (marine grade) d-face d-face tongue & groove plywood AS-NZS 2004 – 2400mm x 1200mm. AUSTRALIAN MADE”
A list of tools used to build this DIY outdoor gazebo roof
Hammer, Measuring tape, chalk line, spirit level, Long straight edge, Hook blade knife, Compressor with framing gun (not necessary), circular saw set to 17mm deep cut, 15-20mm shank galvanised clout nails with a 10mm head, basic blade knife, 2 power cords, tin snips.
At this early point you will have to run a straight edge over the rafters to check that they are all level. If they are not you will need to use a plainer to take some off the tops of the rafters. Asphalt shingles are very low profile / flat and any difference in the rafter height will be seen easily in the finished roof.
TIP “The rafters for this Outdoor Gazebo were spaced at approx 680mm centre’s. It is much better to space the rafters at 600mm centres (centre point from rafter to rafter) so you maximize the use of the plywood and have less cutting”.
Here I have set up a basic plank between two ladders which is usually more than adequate for an outdoor gazebo job like this.
This roof was 25 degree roof pitch. The minimum pitch for asphalt shingles is 9.5°. Between 9.5° pitch and 18.5° pitch you will need to use a special waterproofing barrier eg.. IKO Armourguard – which is an adhesive backed rubberised membrane roll. It is also acceptable to use a double layer of asphalt saturated felt material. Between 60° pitch and vertical (steep slope) you will need to self seal each tab of asphalt shingles
TIP “Both on steep slopes and in high wind areas you should place a small dab of tar under each tab. This will prevent blow off.”
I am checking the position of the plywood so that it comes to the outside edge of the Fascia board. I am spanning the plywood the long side horizontally which is manufacturers guidelines. Always try to stagger the sheets of plywood for extra strength.
TIP “Butt the tongue and groove ends of the plywood tight together but on the short sides leave a 2 – 3mm gap to allow for any expansion the plywood may have.”
Once you have the first sheet of plywood in place you can hammer in a couple of nails to hold. Don’t hammer the nails where you are likely to cut the ply eg… on the end rafter or down the hip.
TIP “Plywood will generally have a stamp on one side with ‘A-Bond AS/NZS 2004….’ lay this side facing up with all sheets for a clean underside and easier joining”.
Here I am snapping a chalk line on the centre of the rafter for a clean straight cut. At this point measure the blade on your circular saw to cut exactly to the depth of the plywood to avoid any mistakes.
Simply cut straight up the chalk line. Some of the waterproofing chemicals in plywood are known to cause cancer so be sure to use a basic mask. Here I’m holding my breath – I Think!!
Sawdust on the plywood is very slippery so keep it clean. As you can see we are creating a fantastic deck that you can walk on as much as you like. No denting metal or cracking tiles on this outdoor gazebo.
Click here to go to DIY gazebo covered patio guide Part 2.