- Asphalt shingles shall conform to CSA Standards A123.2-M1979 Type M
- Asphalt saturated sheathing paper shall conform to CAN2-51.32-M77
- No. 15 asphalt saturated felt (non-perforated) shall conform to CSA A-123.3M
- Eave protection shall be minimum 28lb. asphalt saturated felt or self-adhering proprietary product designed for this purpose
- Fasteners shall be large headed roofing nails, galvanized steel or aluminum. Nails shall have a nominal shank diameter of 3mm and a minimum head diameter of 9.5mm. Nails can be hand or power driven.
- Fasteners length shall be sufficient to penetrate 20 mm into the roof deck. Nails shall be barbed or rough shanked and shall be a minimum of 11-gauge. The nail head diameter shall be a minimum of 3/8”. All fasteners shall be driven straight flush with the shingle surface.
- Shingles shall be applied according to methods outlined by the National Standards of Canada. Roof slopes 1:3 and steeper shall conform to CAN3-A123-M85. Roof slopes 1:6 to less than 1:3 shall conform to CAN3-A123.52-M85
- Typical flat roof installation shall be two ply modified bitumen consisting of minimum base sheet of 2.2mm thickness with minimum 95g/m2 non-woven fibrous glass reinforcement, Type 2, Class C, Grade 1, and conforming to CGSB 37-GP-56M and torch grade modified bitumen cap sheet: minimum 4.0mm thick, granular with minimum 250g/m2 non-woven polyester reinforcement, Type 1, Class A, Grade 2, and conforming to CGSB 37-GP-56M.
As you can imagine, good places for leaks to develop are roof penetrations or anywhere the roof joins with walls and chimneys. To help prevent these leaks from occurring, a corrosion-resistant metal flashing is typically applied.
The Ontario building Code and the N.R.C.A. has minimum requirements; therefore these minimum requirements must be followed in order to keep the warranty in effect:
- Step flashing materials shall consist of no less than .312mm in thickness and counter flashing no less than .576mm thickness.
- The roof/wall intersection shall be protected with sheet metal that extends no less than 100mm each way from the intersection.
- Step flashings are rectangular in shape and 50mm longer than the exposed face of the roofing shingles. They are bent so as to extend out a minimum of 50 mm over the roof deck, with the remainder on the wall surface. Each flashing is placed just up roof from the exposed edge of the shingle which overlaps it and is secured against the wall. Each element of the flashing will lap the next by 35mm. The finish siding (counter) is brought down over the step flashing to serve as a cap flashing.
- Vertical front wall flashing is applied pre-bent up the vertical wall surface approximately 75mm. and down overtop of the shingles approximately 75mm. Shingles are applied up the roof slope until a course must be trimmed at the base of the vertical wall. Metal sheets are typically applied in 8 ft. lengths over the last course of shingles embedded in asphalt plastic cement. Wall flashing shall be fastened every 12”. Where side laps are necessary, overlap the pieces at least 6”. Cladding or shingles may serve as counter flashing.
- Flashing intersects a masonry wall such as chimney, side wall a counter flashing shall be installed and embedded not less than 11/2 “ in the masonry and over lap the step flashing. This will be done by cutting out a mortar joint to a depth of min. 11/2 “ and inserting the bent edge of the flashing into the cleared joint. Refill the joint with Portland cement mortar caulk. This will prevent maintenance of having to recaulk flashing.
- Back Pan Flashing is installing a Shingle and Double Chimney extending up the chimney at least 6” and up the roof deck at least 12′, with appropriately formed side and corners. Apply the first course of shingles to cross the roof deck on the upper side of the chimney to be trimmed back 2” from the chimney vertical. Bend the metal to extend 2” past the upper sloping sides of the chimney. This allows quick water drainage, prevents water from working up under the shingles and promotes a natural cleaning of debris from the high side of the chimney. Apply shingles up the front vertical edge of the chimney. Apply base counter flashing up the front vertical wall, step flashing to the side as described previously. Counter flash chimney with a continuous piece of metal as described previously to the left and right sides of the chimney.
- Drip edge flashing shall be installed along the eaves perimeter of home consisting of 0.024 pre-painted metal. The Drip edge shall be pre-formed and installed in 8-10′ lengths where applicable. The metal will be fastened every 24” along the roof slope. Overlap metal to a min. of 2” as necessary without fasteners to allow for the expansion. Drip edge is designed for the prevention of ice and water seepage under the shingle edges. This will also offer support to the shingles and provide a uniform and straight edge. Moreover, it will also protect your fascia board from rotting out.
- Rake edge flashing shall be installed along the rake edge perimeter of home consisting of 0.024 aluminum pre-painted. The Rake edge shall be pre-formed and installed in 10′ lengths where applicable. The metal will be fastened every 24” along the roof slope starting at the lowest point, then working toward the highest point. Overlap metal to a min. of 2” as necessary without fasteners to allow for the expansion. Rake edge is designed for the prevention of ice and water seepage under the shingle edges. This will also offer support to the shingles and provide a uniform and straight edge. Moreover, it will also protect your fascia board from rotting out.
- Fabrication of metal shall be form bent with straight sharp lines and angles into true planes. Double-back exposed edges minimum of 1/2″. Sheet metal to be installed in a uniform manner, free of oil canning, level and true to line.
- All metal flashings that are checked off as “refurbish” in the “Contract Specifications” (scope of work) are deemed to be very satisfactory by our professional estimator and will therefore also be covered under full warranty. Step or counter flashing shall consist of corrosion resistant galvanized steel, copper or aluminum step flashing.
Good ventilation creates a cooler attic in the summer and a drier attic in the winter. In a home with poor ventilation, the heat in the attic may reach 140 degrees. An overheated attic combined with moisture can be damaging to the roof deck and to the shingles. This will cause them to distort and deteriorate prematurely.
In the winter, vapour pressure causes the moist warm air from the building interior to escape into the attic. This could be the result of air leaks such as electrical outlets, plumbing fixtures, recessed pot lighting, open air space at the roof/wall junction, attic hatches or a breach in the air/vapour barrier. It’s also not uncommon to see bathroom and clothes dryer fans evacuate directly into an open attic space. All insulated attic space shall be ventilated with openings of not less than 1 sq. ft. for every 300 sq. ft.
A rotted wood deck will affect the nail holding capacity. Severe condensation may affect the thermal efficiency of the insulation. Interior leaks can sometimes be a direct result of condensation, not a failed roof.
Ice dams develop when warm air (heat loss from the building interior) melts the bottom portion of accumulated snow above. Water runs down the slope towards the eaves. As the water trickles past the lower and unheated sections of the roof (overhang) it freezes. This wall of ice continues to build forming an ever expanding dam. As the melting snow continues, it finds no where to go but backwards underneath the shingles and eventually inside your home causing damage.
Ventilation can be a good start at mitigating these problems. We must be very careful though, as simply adding extra vents may not be the solution. In fact, it could be the wrong approach. In some cases, adding ventilation will actually pull more moist air up to the attic and make the problem worse. The best way to fix a wet attic is to control and stop air movement from the house.
As required by the Ontario Building Code, The National Roofing Contractors Association and the Shingle Manufacturers, your roofing system will require:
● All insulated attic space shall be ventilated with openings of not less than (1) sq. ft. for every (300) sq. ft.
This must balance equally between the soffits (intake) and the roof vents (exhaust).
● The ventilation shall be designed to prevent the entry of rain and snow.