Underlayment Requirements for BP Shingles
The table below describes underlayment requirements for all BP shingles. Building Products of Canada Corp. always recommends the use of underlayment under all asphalt shingles as a better roofi ng practice recognized throughout North America. Certain products in the table below may not be available in all regions. It is recommended to consult minimum local building code requirements before applying BP products. For any additional information concerning our products, please contact your local BP representative.
| BP Shingles |
Minimum Slope |
Underlayment Required |
Underlayment Recommended² |
• Manoir
• Everest
• Harmony
• Mystique |
1:4 (3/12) |
1:4 to <1:2 (3/12 to <6/12) 1 |
1:2 (6/12) and above ³ |
• Yukon SB
• Mirage GS
• Dakota |
1:6 (2/12) |
1:6 to <1:2 (2/12 to <6/12) 1 |
1:2 (6/12) and above ³ |
1] Special low slope application method is required when shingle is installed on roof slopes between 1:6 and 1:3 (2/12 and 4/12). Please refer to Asphalt Shingle Application Instructions for more details.
2] For roof slopes greater than 6/12, the use of underlayment continues to be recommended by the industry throughout North America as a better roofing practice. However, following careful examination of the roofing project, spec writers can omit, at their discretion, the use of underlayment on roof slopes greater than 6/12. Please take note that all other application requirements remain in effect as printed on application instructions and on individual shingle wrappers.
3] The following is Building Products of Canada Corp.’s position with regard to the use of underlayment when installing BP fiberglass shingles and its impact on our warranty coverage.
Our warranty on water leakage is conditional to the use of underlayment. Regardless of the use or absence of an underlayment however, Building Products of Canada Corp. will warrant that its fiberglass shingles are free from manufacturing defects as per the terms of our BP Shingle warranty.
For the benefit of fiberglass shingle users who are not applying underlayment, we include the positions of CASMA, Local Roofing Associations and Underwriters Laboratories regarding the use of underlayment:
As stated in CASMA Technical Bulletin No. 22: “Glass shingles, due to their light-weight reinforcement, are [...] flexible in warm weather [...]. Consequently, when applied to the roof, they often take the shape of (i.e. “telegraph”) whatever lies beneath them. [...] As the glass shingles are applied, there is a natural build-up of layers of shingles, which is essentially how the finished roof sheds water. In the first few years, as the summer sun heats up the roof, the glass shingles soften and slowly conform to the shape of the layers underneath. Just above the lower exposed edge of each shingle course, lies the concealed top edge of the shingle two rows lower on the roof. This concealed top edge may form a small “trough” in the unexposed part of the shingle. On lower roof slopes (those below 8:12), water that enters this trough (through the shingle cut-outs or joints in the overlying shingles can travel laterally along the trough, and penetrate the shingle layer through misplaced fasteners or shingle joints. This potential for leaks due to troughing is one of the reasons CASMA strongly agrees with the standard industry requirement to use an asphalt-saturated felt underlayment under glass fi bre shingles.”
Many Local Roofing Associations require the use of asphalt-saturated felt underlayment under shingles to comply with their respective warranty program requirements. Finally, the installation of underlayment under fi berglass shingles is mandatory to comply with Underwriters Laboratories Class A Fire Rating requirements.
Wind Warranties For BP Shingles
Building Products of Canada Corp. has always strived to make the best asphalt shingles possible. Advancements in the factory-applied adhesive allowing shingles to seal once installed on the roof, BP offers some of the best wind warranties in the industry. Depending on the BP shingle and the method of installation, homeowners can get protection from winds up to 220 km/h or 135 mph (see Table below).
Standard Wind Warranty :
All BP 3-Tab Shingles, when installed using standard application instructions, are warranted against wind damage or shingle displacement for winds up to 115 km/h (70 mph). All BP Laminate Shingles are now backed with BP’s innovative Weather-TiteTM Technology. These Shingles now include 2 Sealant Bands which warrant against wind damage or shingle displacement for winds up to 180 km/h (110 mph).
High Wind Warranty :
To qualify for High Wind Warranty, which warrants against wind damage or shingle displacement for winds up to 130 km/h (80 mph) for all 3-Tabs and 220 km/h (135 mph) for all Laminates, shingles must be fastened using 6 nails and all shingles located at the roof edges must be cement together in a 10 cm (4”) wide layer of Asphalt Plastic Cement. Please see the table below for the High Wind Warranty for each BP Shingle model. If above special application instructions are not followed, shingles will revert to the Standard Wind Warranty of 115 km/h (70 mph) and 180 km/h (110 mph) respectively.
* For detailed information on Application Instructions, please click here.
Also, refer to our Weather-TiteTM Technical Bulletin #4.
Installation of Laminates Over Existing Roofs
After careful review of evolving industry practices, Building Products of Canada Corp. has come to the conclusion that multiple layer installation of BP laminate shingles is acceptable providing the old roofing material meet the following requirements:
• Old roof must be dry, clean and provide a smooth surface to the new layer of shingles;
• Damaged, curled, broken, buckled or loose shingles are replaced;
• To ensure an even surface, the old roofing is swept clean prior to the installation of the new layer of shingles;
• Fasteners are of sufficient length to penetrate deep enough in the wood deck;
• When the shingle exposure of the old roofing material is different from the exposure of the new shingles:
- Apply new shingles using butt edge application method (or nesting method) ;
- The top of the headlap of the new shingle is nestled against the bottom edge of the exposed portion of the old roofing shingle;
- The new shingles are applied to prevent any throughing or bridging of the new shingles being installed;
• It has been determined that the load bearing capacity of the building structure is sufficient to withhold more than one layer of shingles;
• Multiple layer application is allowed in respect with local bylaws or building code(s).
Please take note that all other application requirements remain in effect as printed on BP application instructions and on individual shingle wrappers. Lastly, Building Products of Canada Corp. will not be responsible for appearance and throughing problems related to multiple layer installation, such problems being typical of this type of installation.
Weather-TiteTMTechnology
Laminate Shingles are now backed with BP’s innovative Weather-TiteTM Technology. These Shingles now include 2 Sealant Bands which provide superior protection in the toughest weather (see Table 1 WIND WARRANTY and Table 2 TEST RESULTS).
| Table 1 |
| Shingles |
Standard Wind
Warranty |
High Wind
Warranty |
• Manoir
• Everest
• Harmony
• Mystique |
180 km/h (110 mph)
|
220 km/h (135 mph) |
In order to make the distinction between the application of shingles offered in the West verses those offered in the East (see Figure 1).
*Manufactured in the West. Sealant Bands are located on the Top / Front of each Shingle (also see Figure 2 a).
**Manufactured in the East. Sealant Bands are located on the Bottom / Back of each Shingle (also see Figure 2 b)
WEST : In the Prairies as well as in British Colombia, 2 Sealant Bands are located on the Front of the Harmony and MANOIR shingles. Also included are two Cellophane Strips, which are protective strips located on the Back of each shingle and should not be removed (see Figure 2 a).
Nails need to be applied between the adhesive dabs (see Figure 3).
EAST : In the Atlantic, Ontario and Quebec regions, 2 Sealant Bands are located on the Back of the Everest and Mystique shingles. Also included on the Back are two Cellophane Strips, which are protective strips that should not be removed (see Figure2b). ‡(see NOTE below)
Nails need to be applied on the nailing line (see Figure 3).
‡NOTE: MANOIR, although manufactured in the West, this shingle is sold in both Western and Eastern regions and therefore must be applied by nailing between the adhesive dabs.
Huber Engineered Zip Roof System Sheathing
Building Products of Canada Corp. (BP) warrants its roofing asphalt shingles when installed according to BP instructions over Huber Engineered ZIP Roof System Sheathing. The sheathing must be applied in accordance to the requirements of Huber Engineered Woods.
The design professional and/or contractor are responsible to establish the compliance of the roofing system with the building code requirements.
BP shall bare no responsibility under its warranty for:
• Defects or damage caused by materials used as roofing base over which the shingles are applied;
• Damage to the shingles caused by movement, settlement, distortion, failure or cracking of the roof deck;
• Defective manufacturing or improper installation of deck fasteners;
• Defect, failure or water leakage caused by the application of its shingles not installed in strict compliance with BP’s instructions.
BP Shingles On Slopes Between 2/12 and 4/12
Building Products of Canada Corp. would like to point out certain guidelines concerning the application of BP shingles on roof slopes between 2/12 (1:6) and 4/12 (1:3). The following table will list which BP shingles can be installed on specific roof slopes. It must be noted that under any circumstances, no BP shingle can be installed on roof slopes below 2/12 (1:6).
| Shingles Type |
Minimum Slope |
Slope 2/12 to <3/12 |
Slope 3/12 to <4/12 |
| Laminated Shingles |
• Manoir
• Everest
• Harmony
• Mystique |
Shingles cannot be installed |
Shingles can be installed using
standard low slope application¹ |
| 3-Tab Shingles |
• Yukon SB
• Mirage GS
• Dakota |
Shingles can be installed
using standard low slope application1 |
Shingles can be installed
using standard low slope
application1 |
1] Shingle will only be warranted for the full term of the warranty if proper low application is followed.
Low Slope Application for BP Shingles:
BP’s Yukon SB, Mirage GS and Dakota shingles can be applied on decks having a slope between 2/12 to 4/12 (1:6 to 1:3) and BP’s Manoir, Everest, Harmony and Mystique can be applied on decks having a slope between 3/12 to 4/12 (1:4 to 1:3). The installation procedure for the shingles is the same as for standard slopes (1:3 and over) but the Eave Protection and Underlayment must be done according to one of the 3 following methods:
Method 1:
As described for normal slopes, for optimum protection against water penetration, use a single ply of GRIPGARD, GRIPGARD SX or PROGARD ULTRA over the entire wood deck. They are strong, self-adhesive, roofing membranes are applied by peeling off the release / film paper backing as it is unrolled.
Starting at the low point of the roof, apply GRIPGARD, GRIPGARD SX or PROGARD ULTRA by laying the roll horizontally. End laps must be a minimum of 15 cm (6”). Each succeeding course should be lapped 7.6 cm (3”) over the preceding, lower course. Felt underlayment is not required when PROGARD ULTRA is installed over the whole roof.
Method 2:
Eave protection consists of a single ply of GRIPGARD, GRIPGARD SX or PROGARD ULTRA Waterproofing Membrane laid horizontally and extending up the roof, from the eaves to a point at least 61 cm (24”) beyond the interior wall line. End laps must be a minimum of 15 cm (6”). If more than one width is required, overlap the second course 10 cm (4”) over the first (see Figure 1).
Next, install the underlayment. This calls for a double layer of BP’s GRIPGARD, GRIPGARD SX, PROGARD ULTRA, n°15 CSA Pro Felt, n°15 Asphalt Felt Plain, DECKGARD or other BP roofing asphalt felt underlayment. Lay horizontally over the rest of the roof. Underlayment must be applied over the entire roof deck. Start with a 91 cm (36”) wide sheet overlapping GRIPGARD, GRIPGARD SX or PROGARD ULTRA by 43 cm (17”). Apply a second 91 cm (36”) sheet, overlapping the first one 48 cm (19”), leaving 43 cm (17”) exposed. Thereafter, 91 cm (36”) sheets are laid, each to overlap the upper 48 cm (19”) of the preceding course, until the rest of the roof deck has been covered. Each course of felt is nailed towards its upper edge with only enough nails to hold it in place until the shingles are applied (see Figure 2).
Method 3:
This special procedure calls for an eave protection made up of a double layer of BP n°15 Asphalt Felt Plain or BP Standard Asphalt Sheathing which is both cemented and nailed in the eaves and nailed only over the rest of the roof. Start application with a 48 cm (19”) wide starter course of felt, laid along the eaves flush with the edge of the roof. The underlayment must be cemented from the edge of the roof up to a point at least 61 cm (24”) inside the interior wall line. Continue with a full width 91 cm (36”) of felt over the starter course and flush with the edge of the roof, completely covering the 48 cm (19”) starter course. Each course of felt in the eaves is cemented to the preceding course using Asphalt Plastic Cement, applied at the rate of 1 L/m2 (1 gallon / 50 ft²). A 4 kg container of Asphalt Plastic Cement will cover approximately 2.3 m2 (24.5 ft²), 1.5 mm (1/16”) thick. Asphalt Plastic Cement must be applied uniformly with a comb, putty knife or notched trowel so that at no point will dry felt touch dry felt. Special care must be taken to ensure that the proper amount of Asphalt Plastic Cement is applied - refer to the label. The felt is pressed firmly into the cement to ensure proper bonding. Nail sufficiently to hold it in place until the shingles are applied. Continue applying Asphalt Plastic Cement and felt this way up to a point at least 61 cm (24”) inside the interior wall line. Beyond this point 91 cm (36”), sheets are laid, but without Asphalt Plastic Cement, lapping each course 48 cm (19”) over the preceding one. Each course of felt is nailed sufficiently to hold it in place until the shingles are applied (see Figure 3).
Ventilation:
All roof structures must be provided with through ventilation to prevent entrapment of moisture-laden air beneath the deck. Ventilation provisions must meet or exceed current National Building Code requirements. In the U.S.A., check local building codes for minimum requirements. In general, as specified in most building codes, for a low-slope roof or one with cathedral ceilings, every roof space or attic above an insulated ceiling must be ventilated with openings to the exterior to provide an unobstructed vent area of not less than 1/300 ft2 of the total insulated ceiling area. This ratio does not apply for all roofs. A low slope roof or one with cathedral ceilings requires twice (2x) the ventilation or a ratio of 1/150 ft2. The vents used may be roof-type vents, eave-type vents, gable-end type vents or any combination, and should be uniformly distributed to ventilate each roof space. When calculating the net free area (unobstructed open area), be sure to factor in any obstacle to free air circulation such as screens, grids, louvers, blades, etc.
There must be at least 8 cm (3”) of space between the insulation in the attic and the deck. If insulation was added to the deck without leaving space for air flow, the ventilated soffit might not be able to do the job it was intended to do.
The shingle warranty will only be valid if all roof structures are provided with proper through ventilation.
Appearance of Shingles Installed In Cold Temperature
One noticeable consequence of installing asphalt shingles in cool or cold temperature is that the material will not immediately lay fl at on the roof as it does when installed in warm / hot environmental conditions.
The combination of the mat and asphalt produce a material that is more rigid as its temperature decreases. This is true for all shingles but is more pronounced in the case of laminate shingles. The varying thickness of the shingle between the laminate sections (double layer) and the shim / headlap (single layer) tend to accumulate in the bundles and produce a shingle that is curved or uneven. Simply nailing the shingles to the roof in cold temperature does not flatten the shingle surface itself. This can result in a roof that looks irregular, curled or crinkled.
Roofing asphalt shingles need to be subjected to warm temperatures before they settle down on the roof and give the regular appearance expected of them.
Essentially, if the shingles are installed in cold temperature conditions, such as late in the fall or during winter, the building owner may have to wait until a warm period before the shingles lay down fl at on the roof.