Building Code vs. Manufacturers Recommendations
Choosing a roofing contractor can be a very confusing process. Specifications can vary, “professional” recommendations can be completely different and deciding between right and wrong can be overwhelming. At Dayus Roofing we always recommend to install a roofing system that adheres to both the Ontario Building Code as well as all shingle manufacturers’ recommendations. Here we break down the differences between the two and help you understand what’s required and what’s recommended.
Highlights of the Ontario Building Code
1) NAILS - Nails used for roofing shall be corrosion-resistant roofing or shingle nails conforming to CSA B111, “Wire Nails, Spikes and Staples”. Nails shall have sufficient length to penetrate through or 12 mm into roof sheathing.
Hopefully a roofing contractor never makes a mistake with nails.
2) VALLEY - Closed valley flashing shall consist of sheet metal, self sealing composite membranes consisting of polyethylene and bituminous material or one layer of either Type S smooth surface roll roofing or Type M mineral surface roll roofing (mineral surface down) not less than 600 mm wide, and nails shall not penetrate the flashing within 75 mm of its edge or 124 mm of the bottom of the valley centerline.
Translation: In closed style valleys, where shingles overlap and metal is not used, an ice and water shield or leak barrier membrane must be applied to the deck prior to shingling.
3) WALLS - The intersection of shingle roofs and masonry walls (and walls clad with other than masonry) or chimneys shall be protected with flashing.
Often times contractors will quote to re-use existing flashings or omit flashings altogether. This is a critical element to a roofing system and a problem area if not installed properly.
4) CHIMNEY SADDLE – Chimney saddles shall be installed where the upper side of a chimney on a sloping roof is more than 750 mm (29.5 in) wide. A chimney saddle need not be installed if the intersection between the chimney and roof is protected by sheet metal flashing that extends up the chimney to a height equal to at least one-sixth the width of the chimney, but not less than 150 mm (5.9 in), and up the roof slope to a point equal in height to the flashing on the chimney, but not less than 1.5 times the shingle exposure.
Translation: If you have a chimney more than 2’5” wide where a roof slope directs water towards the back side, it is recommended you install a saddle to direct water around the chimney. However, you can use a flashing that is 12” tall and runs 12” up the slope for a 6 foot wide chimney. This is another area that is often overlooked by contractors and can lead to problems if not addressed.
5) EAVE PROTECTION – Eave protection shall be provided on shingle, shake or tile roofs, extending from the edge of the roof a minimum of 900 mm (36 in) up the roof slope to a line not less than 300 mm (12 in) inside the inner face of the exterior wall. Eave protection is not required over unheated garages, carports and porches, where the roof overhang exceeds 900 mm (36 in) measured along the roof slope from the edge of the roof to the inner face of the exterior wall, on roofs with slopes of 1 in 1.5 (8/12) or greater. Eave protection shall be laid beneath the starter strip and shall consist of, No. 15 asphalt-saturated felt laid in two plies lapped 480 mm and cemented together with lap cement or self-sealing composite membranes consisting of modified bituminous coated material.
THIS IS THE MOST OVERLOOKED DETAIL IN ROOFING QUOTATIONS! Even some of the most “reputable” contractors in Windsor Essex will tell their customers this is not required to save costs and keep their price attractive. Many contractors will recommend standard No. 15 felt paper for 3’ and a bare deck to the peak. This is a BIG RED FLAG.
6) UNDERLAY BENEATH SHINGLES – When underlay is used beneath shingles, it shall be (a) asphalt-saturated sheathing paper weighing not less than 0.195 kg/m2, or No. 15 plain or perforated asphalt-saturated felt. Underlay used beneath wood shingles shall be breather type.
Underlayment is not a requirement with asphalt roofing but is highly recommended by all shingle manufacturers and Dayus Roofing.
7) STARTER STRIP – A starter strip shall be installed along the lower edge of the roof so that it extends approximately 12 mm (1/2 in) beyond the eaves and rake of the roof. Starter strips shall either be pre-manufactured starter strops or at least shingles of the same weight and quality as those used as a roof covering with tabs facing up the roof slope.
For a complete copy of the Ontario Building Code 2012 and more information regarding specialty roofing details please CLICK HERE and refer to page 506-513, Section 9.26. For Roofing.
It may seem as though manufacturers encourage you to go above and beyond the building code as a means to sell more of their products. However, experience has taught us that small investments in recommendations that are above code can have a large impact on the overall success of a roofing system. Some manufacturers offer extended warranties and accessory warranties when you buy a certain number of their products, but this is not a requirement for a successful roof. (Click here to compare warranty choices WARRANTIES PAGE LINKED). Below is a list of manufacturer’s recommendations that are not enforced by building code.
1) STARTER STRIPS – Manufacturers recommend you use a pre-manufactured starter strip because they lay flatter and work more cohesively with the rest of the roofing system, whereas the building code does allow you to use “at least shingles of the same weight and quality as those used as a roof covering”. With laminate shingles and with some designer profiles shingles, installers can cause problems if these shingle types are not trimmed properly. A starter strip is a good way of avoiding this problem.
2) UNDERLAY BENEATH SHINGLES – Manufacturers recommend, regardless of the roof slope, to use an underlayment over the complete roof deck prior to shingle installation. Some contractors will try and differentiate their proposals by promoting different types of underlayments. Synthetic underlayments, for example, are becoming increasingly popular. However, because of the relative age of these products there is no proof in real world testing that they will help to improve the longevity or protection of your roof. Manufacturers will encourage you to use their specific branded product but recommend No. 15 felt as a minimum.
3) EAVE PROTECTION – Manufacturers recommend, regardless of the roof slope, to install a minimum 900 mm of leak barrier or ice and water shield to the eave edge of the home prior to shingle installation. They will encourage you to use their branded products but this is not required. The building code states that for slopes greater than 8/12 that eave protection is not required. However, experience has taught us that even the steepest roofing systems can experience ice build up and damming that can force water under your shingles.
4) FILM SURFACED LEAK BARRIERS – Manufacturers recommend that in low sloped areas of your home, and critical areas on a roof, to use a film surfaced leak barrier or premium ice and water shield. Most standard leak barrier products have a granulated coating that inhibits the overlapping edges of the membrane to adhere entirely. Film surfaced leak barriers have smooth finishes for a tighter adhesion and superior protection in the most difficult roofing areas.
5) DRIP EDGE – Although not stated in the building code, manufacturers recommend that you install a drip edge to the eave and gable ends of your home underneath the eave protection. The drip edge is pc of aluminum that supports the overhanging edge of the shingle and protects the transition from the fascia to your roofline from water penetration. Many contractors will quote to re-use the drip edge or omit it altogether to save time and costs. However, the drip edge is a critical component of a successful roofing system and is relatively inexpensive to have installed.
6) VALLEY – It is recommended by all manufacturers to install an ice and water shield or leak barrier extending a minimum of 18” on each side of the center of all valleys. Manufacturers will encourage you to use their leak barriers under closed cut valley installation. This is not required but can help to enhance your warranty coverage. In open style valley applications, manufacturers recommend that you use 2 applications of ice and water shield to “sandwich” the piece of metal you lay through the valley.
7) VENTILATION – Manufacturers will encourage you to upgrade your ventilation to ridge ventilation or more premium priced ventilation alternatives, but this is not required. What is important is that you abide by all codes and NEVER mix ventilation styles within a single attic space. It is OK to use different types of vents (and is sometimes required depending on the attic setup) so long as the attic spaces are completely separated by a dividing wall. (Click Here to learn more about ventilation LINK TO Ventilation PAGE)
Check with a sales representative at Dayus Roofing for more information on any of the above Code requirements and manufacturer’s recommendations. Depending on the purpose of roof you are installing there are acceptable ways to cut costs on a project. Knowing the difference between building code requirements and manufacturer’s recommendations will ensure you make the right roofing decision.
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Roofing 101 Topics
- Roof Design Types
- Early Deterioration
- Warning Signs
- Problem Areas
- Building Code
- Deck Preparation
- Material Options
- Metal Flashings
- Valleys & Ridges
- Common Mistakes
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