Hip and ridge conditions have proven to be the weak point observed post hurricane in all roof covering types. The occurrence of these failures on tile roof systems have been reduced significantly since the FRSA-TRI Florida High Wind Concrete and Clay Tile Installation Manual (the manual) became effective in August of 2005 as the 4th Edition. This and subsequent editions have been revised to significantly improve the performance of tile hip and ridge. When the installation techniques described in the manual are followed, hip and ridge, as well as other portions of tile roofs, perform admirably, often with no observed failures. The failures of tile hip and ridge can almost always be traced back to applications that were not in compliance with the manual or the HVHZ roofing application standards (RAS), which can be be used in lieu of the manual. The purpose of this article is to help clarify what is required in the manual as well as addressing proper roofing practices.
The hip and ridge table below outlines the different parameters for hip and ridge attachment options and is where our understanding of proper applications begins. Start in the first column to choose the method you will use to install the field tile. If using a structural member, choose which type in the second column, follow the installation guidelines in the appropriate row or the manufacturer’s recommendations. We will address the use of mortar as a structural support later. First, let’s review each of the structural member options.
Metal Member
– Set member in plastic cement or compatible sealant. Fasten 6” on center on each side of the metal flange with minimum 1-1/4” ring shank roofing nails. If mechanical attachment of the member is not used, install the member with foam per the manufacturer’s instructions. The member should be cantilevered to provide a base for the adhesive for the starter tile. Review the following drawings that demonstrate why cantilevering is important and several different options when doing so.
Metal Member
– Typical Non-cantilevered Installation (not recommended). This method does not allow the adhesive to make
continuous contact
with both the ridge cap stater and the support at the lower bottom end of the support.
The following drawings are structural hip and ridge support options that allow adhesive to make continuous contact with both the bottom of the tile and the structural support.
Metal Member
–
Notched Cantilever
Metal Member
–
45º Cantilever
Metal Member
–
Wood Extension
Metal Member with Perforations
Metal member with perforations for improved foam adhesion.
Metal member installed at ridge with sealant.
Wood Member
– Fasten 18” on center with four #8 screws per metal strap or H-bracket. Each attachment point shall have two fasteners on each side of the wood member. The fasteners shall be spaced evenly on the metal strap or H-bracket with the attachment holes parallel to the hip or ridge. The straps and H-brackets shall be a minimum of 26 gauge. All materials must be compatible with each other. If mechanical attachment of the wood member is not used, install the member with foam adhesive per the manufacturer’s instructions. Member must be pressure treated and must be of sufficient height to maintain an even plane of trim tiles.
Wood Member – 45º Notched Cantilever
Wood Member – Notched Cantilever
Metal Brackets – H-Bracket or strap shall be a minimum of 26 gauge.
Adjusting the height of wood member note: Stacking nailer boards may be used to adjust height. Maximum thickness of 2” per additional nailer board.
Plastic Member
– Install the member with foam per the manufacturer’s instructions. (Coastal)
Plastic ridge support used with code-approved roof tile adhesive.
Metal (with approval), wood and plastic hip and ridge members may be set in adhesive per the manufacturer’s instructions.
Field Tile Cuts at Hip or Ridge
– All cut field tiles adjacent to a hip or ridge shall be attached to the cap sheet and/or the adjacent tile with an approved adhesive, mortar or mechanical fasteners and adhesive.
All field cut tiles (two tiles on each side of hip) and the top course of ridge tiles must be attached to the substrate with code-approved adhesive, code-approved mortar or mechanical fasteners and adhesive.
In situations where the ridge course of tile has been cut, the field cut tile and the full tile course below the cut tile must be attached to the substrate as well. This requirement is designed to minimize any dynamic movement of the field cut tiles, at the most stringent zones of the roof, which may occur during a high-wind event such as a hurricane.
Field tiles shall be cut to and have at least a 1/2-inch clearance from the member.
Cut tiles without nail holes may be drilled, notched and nailed or affixed with tile adhesive, wire or cut tile clips (approved adhesive is the most commonly used method of attaching cut pieces).
Installing Hip and Ridge Tile
Mortar for Attachment
– When using foam or mortar field tile attachment, mortar can be used as a structural attachment. Place a full bed of pre-bagged mortar under the entire tile. Each tile must be fully embedded into the mortar. The field tile secured to the underlayment along with mortar on each trim tile creates the structural bond. Install hip and ridge tile in a continuous bed of FBC-approved pre-bagged mortar as structural support and weather blocking. The entire cavity under the trim tile should be filled with approved mortar. Miter or point-up the hip starter tile to match the intersecting eaves.
Starter Tiles
– All starter tiles must be secured at both ends of the tile either with mechanical fasteners, mortar and/or adhesive. When the field tile is installed with foam or mortar, the starter tile may be installed with an approved mortar and/or adhesive. The starter tile must make continuous contact with the adhesive. See manufacturer’s recommendations or the specific installation techniques for different type support members below.
After the Starter Tile
– Install the next tile, centering over the structural support and/or the starter tile. Continue in the same manner working from the lowest point toward the highest point of the roof. At intersecting junctions (e.g. hip/ridge, ridge/gable, ridge/valley), cut tile to form a solid fit and ensure the first and the last hip/ridge tile is securely fastened. Any exposed fasteners shall be sealed with a UV-resistant sealant. The minimum head lap when installing the hip and ridge tiles is 2”, as stated in the FRSA-TRI manual. It may be necessary to increase the head lap to cover exposed hip/ridge tile fastening holes or adhesive. Cover exposed fasteners with a UV-resistant sealant. Note: Hip and ridge tile can’t make contact with field tile before it contacts adhesive and the member.
On Metal Member
– Place foam under starter tile per manufacturer’s recommendations or secure the head of the tile with one #8 screw and apply adhesive in the gap between the structural support and the tile. The member may need to be cantilevered to provide a base for the adhesive.
Hip and ridge applications for metal member with foam.
Hip and ridge applications for metal member with foam.
On Wood Member
– Place foam under starter tile per manufacturer’s recommendations or drill a hole in the lower third of the starter tile and secure with a mechanical fastener into the wood member a minimum of 1”. Seal the head of the fastener with a UV-resistant sealant. Adhesive may be used in lieu of a fastener as long as the wood member has been cantilevered to provide a base for the adhesive. The gap between the structural support and the tile must make contact with the adhesive. See manufacturer’s recommendations.
The use of mechanical attachment to wood member with tile foam adhesive or other approved tile adhesive placed at hip or ridge overlap is an acceptable application.
Plastic Ridge Structural Support Member
– Place foam under starter tile per manufacturer’s recommendations.
Foam must come in continuous contact with the bottom of the tile and structural support member.
Weather Blocking
– Hip and ridge tiles need to have weather blocking, it is mandatory in Florida for all profiles. It protects the underlayment and flashings. It also provides hip and ridge with finished appearance while increasing the overall life and performance of the roofing system. Mortar, mastic, pressure-sensitive roll adhesives or polyurethane foam can be used. Choose one of the following:
1. Mortar
–Pre-bagged or jobsite mix is used to weather block the longitudinal edges of the hip and ridge tiles and provide aesthetics. A full bed of mortar is placed along the longitudinal edges of the hip and ridge tile either during the application of the hip and ridge tiles or may be packed in after the hip and ridge tiles are installed and the adhesive has cured. Install mortar to seal all voids between the field tile and the hip/ridge tile. Care should be taken to ensure enough mortar is used. The mortar should create a wedge to keep it from dislodging from under the hip/ridge and the field tile junction. Ensure areas are sealed to prevent water entry. After the mortar is packed into place, then apply point-up mortar to the desired finish.
2. Foam
– Is used to weather block the entire cavity of the adjoining planes of field tile to the sides of the structural support. This system uses foam as the weather blocking. There is no mortar placed along the longitudinal edges of the hip and ridge tile. Foam is placed where the field tile abuts the structural support. A bead of foam is placed parallel to the hip and/or ridge and the structural support to tile junction to act as a weather block and is applied prior to the attachment of the hip and ridge tile. Install foam to seal all voids between the field tile and the structural support. Care should be taken to ensure all areas are sealed with adhesive to prevent water entry.
Apply a polyurethane compatible coating to protect the foam from UV exposure.
3. Pressure-sensitive Roll Adhesives
– This system can be used with a wood structural support. The flexible self-adhered membrane is applied in a continuous or step fashion, sealing to both sides of the adjoining field tile a minimum of 2” prior to the mechanical attachment of the trim tile to the wood structural support. The flexible flashing may be visible but should not extend onto the field tile beyond the outside edges of trim tile.
Adhere wood hip and ridge boards with adhesive. Use mortar or foam adhesive as weather blocking.
Mechanically attached wood hip and ridge boards using metal brackets. Use mortar or foam adhesive as weather blocking.
Mechanically attached wood hip and ridge boards using metal brackets. Cover with self-adhered weather blocking.
Adequate amounts of pre-bagged or job mix mortar should be used to insure a proper finish of the weather blocking point-up. Mortar should match the tile finish color.
Gable/Rake
Choose one of the following:
Rake Tile
– Cut and install first rake tile with the exposed length of first course of field tile with factory finish of rake tile towards the eave. Fasten rake tile with a minimum of two 10d nails of sufficient length to penetrate the framing a minimum of 3/4”. Butt each succeeding rake tile to the nose of the field tile above and maintain a constant headlap.
Mortar Finish
– Place mortar bed along roof edge. Point smooth to a straight edge finish.
Installing Rake Tile
Two corrosion resistant fasteners shall be used on rake tile of sufficient length to penetrate the framing a minimum of 3/4”. For tile installations with a 3” head lap, cut the first rake tile to lay flush with the eave course tile. Abut the consecutive rake tiles to course above so that the factory finished butt ends are exposed. Place thick end of rake piece toward ridge.
Had installers used these applications in the past and following them consistently since their implementation, we would not have observed the failures that occurred during recent storms (see failure examples below and to the right). The variables in material consistency associated with mortar itself is one concern. The inconsistency of the installation (placement and quantity of mortar) is the other. The addition of support members creates a more controllable and consistent installation method. This results in fewer failures by providing better uplift resistance.
If installers become familiar with the methods described here and in the manual, we should be able to provide tile roof systems that can resist the uplift forces caused by design windspeed hurricanes. This in turn will help demonstrate how well tile roofs can perform.
FRM
Mike Silvers, CPRC, is owner of Silvers Systems Inc. and is consulting with FRSA as Director of Technical Services. Mike is an FRSA Past President, Life Member, and Campanella Award recipient and brings over 50 years of industry knowledge and experience to FRSA’s team.
Previous Article