Installing roofing shingles is not for the faint hearted. It can be a dirty arduous and dangerous job. It is dangerous because not only can you fall off, but there are lots of places where potential disasters occur, and you can end up with leaks. Using different shingles causes leaks as does not having the correct underlay. For a complete roof a roofing contractor may be the preferred option, however if you think that you can handle the physical difficulties like working on a slope, and making it watertight, then have a go.
A good idea is to make a test roof in your garage. Make the construction in your garage and use two sheets of plywood, and support the plywood with wood so that it slopes at the same angle as your roof. Cover it with all the materials you will use on the roof, it is not an easy job to even maintain straight lines when you are working at an angle. The important part is to install all the flashing.
The flashing are the pieces that connect the roof to all the things that are not roofing. Wherever the shingles touch intersection points, skylights, chimneys, ventilation vents, there is a need for flashing. It is mistakes in this area that often cause future heartache. This working model may seem a ridiculous waste of time and money, but if you can’t make this waterproof what chance do you have on the real roof!
Step 1) The first step to laying the shingles is to establish a starter row. The starter strip, which is a backing for the first visible row of shingles prevents water from seeping into the roof from the gaps between the shingles. This is laid along the eave, which is the edge of the roof, the part which projects beyond the side of the building. Cut the tabs off the shingles, and allow them to overhang the drip cap by 3/4″. Drive in the roofing nails every five inches along the top edge. You can cut your own starter row or purchase pre-cut starter strips. Use the nails every five inches along the top edge.
Step 2) It as this point in the installation of shingles that you need to ensure straight lines. Simply butting the next shingle square with the previous one will never guarantee straight lines. Chalk lines should be snapped over certain key areas, the first one is a horizontal line across the starter strip, will guide your first row. Above this starter row you then nail a row of full sized shingles, using the manufacturer’s specifications for nailing. If this is not available the most usually one nail an inch from each end and also at each cutout 5/8″ below the adhesive.
Step 3) After the first course is laid, snap a vertical line, along the height of the roof which shows the inside edge of the next shingle as you progress upwards. This will indicate the inside edge of all the odd numbered rows. One you have laid this row of shingle, the next vertical will indicate the inside edge for the even rows as you progress upwards.
Step 4) Once you have reached the zenith you need to nail a low through ventilating material over the sheathing at the apex. This lets ventilation in and also keeps water out.
Step 5) The last thing to do is to install soffits to allow ventilation. Cut an opening for an air vent in each of the soffits, fit them into the openings and secure with the specific nails supplied for the purpose.
Also, the metal flashing need to be bent to fit underneath the siding at the top of the rafter ledge. All the gaps between the flashing and the siding have to be properly sealed with exterior caulk, and failure to do this will ensure leaks. The caulk can be smoothed with the application of a wet finger. It is always a good idea to spend a little extra time and put some caulk at the nail heads in the flashing, it gives that little extra peace of mind.