When installing a steep-slope roofing system, several other roofing details need to be applied. These details perform a range of vital functions for the roofing system. Polyglass is a leader in manufacturing, roofing, and waterproofing solutions. Our steep-slope detail installation guides below outline the steps required for installing different details using our range of roofing products and membranes.
Installation Tools
When installing a Polyglass self-adhered roofing system for a steep-sloped roof, a few essential tools are required:
- Roofing hammer
- Utility knives with both straight blades and hook blades
- A 40 pound weighted linoleum roller, steel or silicone hand roller
- A high-quality pair of shears
- Tape measure
- Trowel
- Chalk line
How to Install Steep-Slope Roof Field Details
On steep-slope roofing systems, the roof field is the area where you’ll install most of the other roofing details, such as flashing and valleys. Installing a roof field will give you a stable base to work from.
Step One: Prepare the roof deck by making sure it is clean and free of any debris that could adversely affect the installation of the anchor sheet.
Step Two: An ASTM D226 Type II anchor sheet should be laid loosely on the deck with a minimum of three-inch side laps and six-inch end laps and mechanically fastened according to local building codes unless otherwise specified by Polyglass for the project conditions.
Fasteners should be corrosive resistant, 11 gauge ring-shank “Simplex” type nails with a minimum of one-inch diameter metal disc. These should be installed at a minimum rate of 12 inches.
Step Three: Cut a self-adhering Polystick TU Plus underlayment into suitable workable length sheets. Then lay the material in place, starting at the lowest point. Overlap the seams at a three-inch minimum and end laps at a six-inch minimum.
Step Four: Peel half of the backing off the roll and apply firm even pressure from the center to the outer edges. Then, remove the backing from the remaining half of the roll and apply pressure with a 40 pounds weighted roller.
Hand rollers are acceptable for rolling patches, laps, or small areas of the roof that are not accessible to a large roller or broom.
Step Five: Polystick TU Plus self-adhered underlayment should be back-nailed at the selvage edge seam using the fasteners and spacing noted in Step Two. Install fastenings using the area marked “nail area” on the face of the underlayment.
Step Six: Apply a headlap underlayment layer of Polystick TU Plus to cover the back-nailed area.
Step Seven: For any over-fabric and over-granule laps, apply a six-inch-wide uniform layer of Poly Plus 50 premium modified wet/dry cement or Polyglass PG 500 modified cement in between the laps.
How to Install Steep-Slope Roof Drip Edge Details
Drip edges are essential for protecting a steep-slope roofing system from running water. Roof drip edging can be installed under or on top of the field sheet. We’ll cover the steps for both processes below.
A. Steep-Slope Roof Drip Edge Detail Installation Under the Field Sheet
Step One: Place a six-inch minimum base layer between the deck or substrate and the edge metal. Allow enough extra overlap down the face of the deck, but not longer than the face of the metal edge.
Step Two: Once the base layer is in place, remove the release film and install the product. Use a hand roller to ensure full adhesion to the surface.
Step Three: Next, install the metal edge on top of the base layer and nail it at four inches on center in a staggered pattern. Before installing the Polystick TU Plus field sheet, all metal should be primed with a WB-3000 water-based primer or PG 100 asphalt primer.
Step Four: Allow the water-based primer to dry and install the field sheet to complete this detail, ensuring full adhesion to the surface using a hand roller.
B. Steep-Slope Roof Drip Edge Detail Installation Over the Field Sheet
Step One: Begin installing the Polystick TU Plus field sheet where the edge metal will be installed on the top. The deck must be clean and free of debris. During installation, allow enough material for an overhang at the edge to form a separator between the edge metal and the deck or substrate.
Step Two: Once the field sheet is set in place, remove the release film and install the product, using a hand roller to ensure full adhesion to the surface.
Step Three: Next, install the metal edge on top of the base layer and nail it at four inches on center in a staggered pattern.
Step Four: Install a six-inch piece of underlayment strip in the flanges of the metal edge. The strip should be set in a thin uniform bed of approved SBS mastic such as PolyPlus 50 premium modified wet/dry cement or Polyglass PG 500 modified cement when using fabric or aggregate surface underlayment.
Step Five: Once the mastic is installed, embed the strip in place. Remove the release film and install the product. Be sure to use a roller to achieve full adhesion.
How to Install Steep-Slope Wall Flashing Details
Wall flashing is used to form a waterproof layer that prevents moisture from penetrating the walls of the roof, such as where a chimney meets the slope of the roof. Flashing can be installed both under and over a field sheet, and we’ll detail both methods below.
A. Steep-Slope Roof Wall Flashing Detail Installation Under the Field Sheet
Step One: Install a base layer between the deck or substrate and the metal flashing. This base layer should be large enough to extend a minimum of one inch above the metal flashing on the wall and a minimum of four inches past the edge of the metal flashing on the deck.
Step Two: Next, install the metal flashing on top of the base layer and nail it at four inches on center along the top of the flashing on the wall and near the edge of the metal flashing on the deck.
Step Three: Prime the metal flashing with WB-3000 water-based acrylic primer or PG 100 asphalt primer before installing the Polystick TU Plus field sheet. Check regional product approvals or local building codes for requirements on fastening and primers.
Step Four: Allow the water-based primer to dry and install the field sheet to complete this detail. Remember to use a hand roller to ensure full adhesion to the surface.
B. Steep-Slope Roof Wall Flashing Detail Installation Over the Field Sheet
Step One: Begin by installing the Polystick TU Plus field sheet, allowing for enough extra material so it can extend up the wall a minimum of one inch past the metal flashing. This creates a separator between the metal and the deck or substrate.
Step Two: Next, install the metal flashing. Nail it at four inches on center along the top of the metal flashing on the wall and near the edge of the metal flashing on the deck.
Step Three: Install a six-inch minimum strip of underlayment in the base of the metal flashing. When using fabric or aggregate surface underlayment, the strip should be set in a thin uniform bed of approved SBS mastic such as PG 500 modified cement or PolyPlus 50.
Step Four: Once the mastic is installed, you can then embed the strip in place. Remove the release film and install the product. Be sure to use a roller to achieve full adhesion.
How to Install Steep-Slope Roof Penetration Details
Roof penetration is a general term that refers to details such as air vents, pipework, chimneys, or satellite dishes that might need to be on the roof of a building. Like other roofing details, roofing penetrations can be installed or incorporated both under and on top of the field sheet. We’ll cover both methods here.
A. Steep-Slope Roof Penetration Detail Installation Under the Field Sheet
Step One: To create space between the deck or substrate and the roofing penetration, install a separator sheet onto the roofing deck. This should be a film surface product to allow easy installation for the Polystick TU Plus field sheet. Extend the separator sheet a minimum of four inches past the edge of the base flange of the penetration being installed.
Step Two: Once the separator layer is in place, remove the release film and install the product. Use a roller to ensure full contact with the surface.
Step Three: Next, install the penetration on top of the base layer and nail it at four inches on center or at the perimeter.
Step Four: Before installing the field sheet, prime all metal surfaces with WB-3000 water-based acrylic primer. You can also use PG 100 asphalt primer.
Step Five: Allow the primer to dry and install the field sheet. Utilize a hand roller to ensure full adhesion to the surface.
Step Six: Once the field sheet has been installed, apply a bead of mastic around the gap between the edge of the field sheet and the side of the penetration. PolyPlus 50 premium modified wet/dry cement or Polyglass PG 500 modified cement are ideal for this.
B. Steep-Slope Roof Penetration Detail Installation Over the Field Sheet
Step One: In preparation for affixing the roof penetration, install the Polystick TU Plus field sheet in the position where the penetration needs to be installed. Make sure that the deck is clean and free of debris. Cut out a section of the field sheet to form a target for the roofing penetration.
Step Two: For fabric or aggregate surfaced underlayment, cover the area around the target marker with a thin uniform bed of approved SBS mastic such as PolyPlus 50 premium modified wet/dry cement or PG 500 modified cement.
Step Three: Once the mastic is installed, you can embed the penetration base on top and nail it at four inches on center at the perimeter. After the penetration is embedded and fastened in place, prime all metals with WB-3000 water-based acrylic primer or PG 100 asphalt primer.
Step Four: Allow the water-based primer to dry and complete this detail by installing another piece of underlayment to create a target over the penetration. This piece should extend a minimum of four inches past the edge of the base of the penetration. Apply using the approved SBS mastic discussed above and use a hand roller to ensure full adhesion to the surface.
How to Install Steep-Slope Valley Details
Valleys are used to create water channels to direct rainwater down between two sloped areas of a roof. This prevents standing water from building up and causing damage. There are three types of roofing valleys – weaved, straight-cut, and open. We’ll detail how to install each type down below.
A. Steep-Slope Roof Weaved Valley Detail Installation
Step One: Begin by installing a base or separator sheet, such as an ASTM D226 Type II asphalt felt, to the roof deck per local building codes. Extend the sheet a minimum of six inches beyond the edge of the valley metal.
Step Two: Install the valley metal and fasten it at the edges at four inches on center on both sides.
Step Three: In preparation for installing Polystick TU Plus underlayment, prime the valley metal with WB-3000 water-based acrylic primer or PG 100 asphalt primer. Allow the primer to dry before proceeding with the next step.
Step Four: Lay the material in place, starting at the lowest point and extend it through the valley. Make sure the top of the underlayment extends past the edge of the opposing side of the valley metal. Peel half of the backing off the roll and apply firm, even pressure from the center to the outer edges.
Step Five: Back-nail the selvage edge seam of the underlayment with corrosion-resistant, 11-gauge ring-shank “Simplex” type nails with a minimum one-inch diameter metal disc or metal cap nails at a minimum rate of 12-inches.
Step Six: Once the selvage edge seam is back-nailed, remove the backing for the remaining half of the roll and apply pressure.
Step Seven: To install the second sheet of Polystick TU Plus underlayment, start from the opposing side of the valley, take the product through the valley, and make sure that the bottom of the material extends up past the top of the first sheet installed.
Step Eight: Finally, apply a six-inch-wide uniform layer of Polyglass PG 500 modified cement or PolyPlus 50 premium modified wet/dry cement in between the top and bottom ply on all over-fabric and over-granule laps. Repeat these steps with the underlayment going up the entire valley until completed.
B. Steep-Slope Roof Straight-Cut Valley Detail Installation
Step One: Begin by installing a D226 Type II asphalt felt to the wood deck as a base or separator sheet per local building codes. Extend the sheet a minimum of six inches beyond the edge of the valley metal.
Step Two: Install the valley metal and fasten it at the edges at four inches on center on both sides.
Step Three: Before installing Polystick TU Plus underlayment, prime the valley metal with WB-3000 water-based acrylic primer or PG 100 asphalt primer and allow it to dry.
Step Four: Lay the material in place starting from the right side of the valley at the lowest point. Extend it through the valley, ensuring that the top of the underlayment extends past the edge of the opposing side of the valley metal. Peel half of the backing off the roll and apply firm, even pressure from the center to the outer edges.
Step Five: Back-nail the selvage edge seam of the underlayment with corrosion-resistant 11-gauge ring-shank “Simplex” type nails with a minimum one-inch diameter metal disc or metal cap nails at a minimum rate of 12-inches.
Step Six: Once the selvage seam is back-nailed, remove the backing from the remaining half of the roll and apply pressure. Repeat these steps for each underlayment sheet and continue up the same side of the valley to complete that section of the roof.
Step Seven: After the right side of the valley has been completed, start by installing Polystick TU Plus on the opposite side, making sure to extend the top of the material past the valley’s center and repeat the previous steps for each underlayment sheet course.
Step Eight: When the left side has been completed, mark the line down the valley’s center and cut the top ply only. Use a hook blade to prevent damage to the lower ply of underlayment. Then, cut the top corner of the top ply at a 45-degree angle.
Step Nine: Now apply a six-inch-wide uniform layer of Polyglass PG 500 modified cement or PolyPlus 50 premium modified wet/dry cement in between the top and bottom ply on all over-fabric and over-granule laps.
C. Steep-Slope Roof Open Valley Detail Installation
Step One: Start by installing an ASTM D226 Type II asphalt felt to the wood deck, followed by the W-Valley metal, fastening it at the edges at four inches on center on both sides. Snap two chalk lines along the full length of the valley six inches from the W-Valley metal edge.
Step Two: To prepare for the Polystick TU Plus underlayment, use the chalk lines as a guide and prime the valley metal towards the W-Valley metal edge with PG 100 fast-drying asphalt primer or WB-3000 water-based acrylic primer. Allow the primer to dry.
Step Three: Starting from the valley’s lowest point, lay the Polystick TU Plus material in place and extend it over the previously primed area. Peel half of the backing off the roll and apply firm, even pressure from the center to the outer edges. Cut the top corner of the seal lap at a 45-degree angle and lay the membrane into place.
Step Four: Next, back-nail the selvage edge seam of the underlayment with corrosion-resistant 11-gauge ring-shank “Simplex” type nails with a minimum one-inch diameter metal disc or metal cap nails at a minimum rate of 12-inches.
Step Five: Once the selvage edge seam is back-nailed, remove the backing from the remaining half of the roll and apply pressure. All seal lap seams must be firmly rolled with a hand roller to ensure full adhesion.
Step Six: Repeat these steps for each underlayment sheet course and continue up the same side of the valley to complete that section of the roof. Once completed, start installing the product on the opposite side of the valley, following the same installation steps.
Product Summary
Polystick TU Plus
Polystick TU Plus is a rubberized waterproofing underlayment featuring ADESO Technology. It has high-strength polyester fabric on the upper surface and an aggressive self-adhesive compound on the bottom layer, making it ideal as steep-sloped roof underlayment.
WB-3000 primer
WB-3000 is a water-based acrylic primer that penetrates pores and dries quickly to provide a tacky surface. This helps to enhance the adhesion of self-adhered membranes to a variety of substrates.
PG 100 asphalt primer
PG 100 is a general-purpose asphalt primer with a penetrating compound that provides increased adhesion before installing self-adhered membranes, cement, and mastics.
Polyplus 50 Premium modified wet/dry cement
Polyplus 50 is ideal for flashing details and attaching membranes to steep-sloped roofs. The modified, superior quality formulation is also useful in damp, wet, or even underwater conditions.
Polyglass PG 500 modified cement
PG 500’s high-quality formulation gives it superior elasticity to standard plastic cement, making it suitable for attaching membranes and flashing details to steep-sloped roofs.
Glossary of Terms
What Is a Roof Field?
A roof field refers to the roof area where most other roofing details are installed, such as flashing and penetrations. A roof field often consists of an anchor sheet and an underlayment layer to provide a stable basis for installing other details.
What Is a Roof Drip Edge Detail?
Drip edging helps to direct the flow of water off a steep-sloped roofing system. This helps to prevent ponding conditions that can damage the roof and protect the system’s other elements. Drip edges are typically made from metal flashing.
What Is Roof Wall Flashing?
Wall flashing forms a moisture barrier that prevents water from penetrating the surface of a roof, especially in the joins between horizontal and vertical surfaces such as a chimney stack. Flashing is usually made from metal or pieces of roofing membrane and protects more vulnerable elements of the system.
What Is Roof Penetration?
A roof penetration is a term used to describe any implements or features installed on the roof. These details are necessary for the building’s occupants and can take many forms, such as chimneys, television aerials or satellite dishes, pipework, or air vents.
What Are Roof Valley details?
Roof valleys are types of channels that connect two sloped sections of a roofing system. These valleys help to direct water off the roof and prevent it from causing damage via ponding. There are three common types of roof valleys – weaved, straight-cut, and open.
For more information on steep-slope details, contact your Polyglass Technical Services Representative.