Roofing Terminology Guide for your Phoenix Home Inspection

Terms that the Home Inspector may use in your Home Inspection report


Anti-Ponding Strip:  A device such as beveled cant strip or shop made sheet metal installed at all raised fascia conditions to support the underlayment.

Barge Board:  The ornamental boards installed to conceal lookouts and outriggers which project out from the gable end of a roof.  They can also be called Fascia Rafters.

Batten:  A dimensionally small (1”x2”) strips of wood installed horizontally or parallel to the eave line.  The battens are attached to the roof decking with galvanized (corrosion resistant) fasteners and are used as the fixing point for tile attachment.  On Board and Batten siding, the Batten is the component that covers the exterior sheathing’s seams.

Batten Lugs:  These are the protrusions on the underside of the roof tile that engage the batten boards which hold the tile in place.

Bird Stop:  A closure strip with weep holes located at the first row of curved roofing tile that prevents birds from entering under the tile to make nests.

Cant Strip:  An inclined or beveled strip of material, for changing the pitch of a roof slope or for rounding out the angle between a flat roof and an adjoining parapet.

Clay Tiles:  Roof tiles manufactured from clay, shale, or a similar naturally occurring earthly substance and fired to provide strength and durability requirements.  In Arizona we also commonly use Mexican Clay Tiles which typically do not have the strength and durability associated with a fired Clay Tile.

Closed Valley:  Where the roof tiles are cut to meet at the center of the valley.  This is the most commonly seen valley type associated with Arizona Tiled roofs.  At a home inspection, if there are large trees overhanging the roof, your Home Inspector will likely note on his report that the roofs “drainage paths” are blocked by debris and will recommend periodically cleaning these areas to prevent future water damage to the underlying building materials.  Also, see “Open Valley” for a further explanation.

Composition Shingles:  Shingles which have a central core of cellulous fibers or fiberglass that is coated with modified asphalt on both sides and topped with protective mineral granules.  Composition Shingles come in 1-tab, 2-tab, and 3 tab interlocking styles.

Concrete Tiles:  Roof tiles manufactured from cementitious materials and shall conform to applicable ASTM standards.

Collar Tie:  A Collar Tie is a dimensional piece of lumber designed to tie together the tops of opposing rafters. This helps brace the roof framing against uplift caused by wind. Collar ties must be placed in the upper third of the roof.

Cricket:  When a chimney is located on the slope of a roof, it requires a cricket to angle the rain runoff around the chimney.  This will be a ridged connection between the roof and chimney.  Crickets will also be found on our Arizona flat roofs framed against the parapet walls and between the scuppers to angle runoff towards the scuppers and off the roof.

Dead Load:  This is the vertical load created by all the building materials and components placed within the building and transferred through the structural systems to the foundation.

Diverter:  A sheet metal pan or channel flashing that extends past the eave, cut and tucked back under the pan to divert water away from the exterior wall.

Drip Edge Flashing:  A strip of metal installed at the outside edges of the perimeter roof sheathing which has a 90 degree angle that extends the metal over the top of the fascia and barge board.  The drip edge is flared slightly at its termination over the fascia board so that water drips freely away from the fascia and not down it.

Eave:  The horizontal overhang of a sloping roof.

Eave Riser:  The metal closure strip with weep holes for drainage located at the first row of flat roof tile.

Fascia:  Dimensional lumber (usually a 2x6 or 2x8) that is nailed to the ends of the rafter tails/truss tails.  If you have gutters, the fascia is what they’ll be attached to.

Field Tile:  Any tile that is not placed at the perimeter, ridge, hip, or overhang.

Flashing:  A metal, plastic, rubber, or other waterproof membrane used to prevent the passage of water through a joint in a wall, roof, roof penetration, or chimney.  It’s the material used, and the process of, making roof intersections, terminations, and penetrations watertight on the exterior of a structure.

Flat Profile TileThose tiles defined as having a top surface rise equal or less than ½”.

Gable:  The triangular upper wall at the end of a structure that extends from the eave lines (front & back) to the ridge at the top of the roof.  The Gable truss is the last truss.  It’s the truss that the siding or stucco attaches to.

Head Lap:  The amount of overlap between a course of roofing components and the course above it.

High Profile Tile:  Typically an “S” tile.  A tile which has a height variance of more than ½”.

Hip Roof:  A roof where all sides slope downwards to the walls.  Therefore, a square home with a Hip Roof would have 4 sloping roof sections.  A square home with gable ends would have only 2.

Hip Ridge:  The down-sloping external angle formed by the intersections of two different roof slopes.

Hip TileA tile used to cover a Hip ridge.

Joist RafterA rafter with a slope equal to or less than 2 inches in 12.  A flat roof uses joist rafters.

Live Load:  Any load that is not permanently attached to the structure.  People, furniture, snow, and wind are examples of live loads.

Lookouts:  Lookouts and Outriggers are often confused because they are both found in the same area of the roof and appear to be performing the same function.  They are both usually found at the underside of the eave at a gable end of a structure.  Lookouts are dimensional lumber pieces fit between the last truss (gable end truss) and the barge board.  Their duty is to keep the barge board even along its run from the ridge to the lower fascia and to have a spot to nail the edges of the roof sheathing above the eave.  They do not support the barge board.

Open Valley:  Where the roof tiles are cut back from a roof valley to expose the valley metal.  Many people don’t like the look of an Open Valley on a roof, however, they do help keep tree leaves/debris from clogging the drainage path that is commonly seen with a Closed Valley.

Outrigger:  Please read the “Lookout” definition first.  The outrigger is the piece of dimensional lumber that supports the barge.  Usually the gable trusses top chord (the piece of wood in the truss that the roof sheathing is nailed to) is lower and that allows the Outrigger to run from the second to last truss, over the gable trusses top chord and on to the barge board.  In this situation the outrigger is nailed to the second to last trusses top chord and is supported by the gable trusses top chord.  This is what gives the outrigger the support to handle a load.  Half of an outrigger is hidden from view from the exterior of the building.  The inner half can be viewed from the attic at the last truss bay.  Here, if a cracked or broken outrigger is observed, the area of the roof overhanging the gable is structurally compromised.

Parapet:  Parapet walls are seen on flat roof homes in Arizona.  They are the walls that extend above the roof that prevent us from seeing the roof materials, vents, A/C equipment, etc…

They usually will be mentioned in a home inspection report because of a deteriorating top surface that could allow water into the structural components of the home.

Purlin:  A Purlin is a horizontal piece of dimensional lumber that runs perpendicular to the rafters that supports a roofing system.  Purlins are not commonly used with conventional engineered trusses, but are usually found in conventional roofing support systems that employ rafters, rafter ties, and collar ties.

RafterA sloped beam that supports a pitched roof that the roof sheathing is attached to.  Most current residential structural roofing systems employ engineered trusses.  In those systems the top chord of the truss is the equivalent of the conventional rafter.

Rafter Tie:  A Rafter Tie is a piece of dimensional lumber designed to tie together the bottoms of opposing rafters. This helps keep walls from spreading due to the weight of the roof. When the walls spread, the ridge will sag. A sagging ridge is one clue that the home may lack adequate rafter ties. Rafter ties form the bottom chord of a simple triangular roof truss. They should be placed as low as possible in the roof framing.

Rake:  The sloping edge of a pitched roof.

Rake Tile:  The tile covering the cut ends of the main roofs tile along the Rake.  Rake tile will cover the upper portion of the Barge Board above the gable.

Ridge:  The top intersection of two sloping roofs.  The apex of the roof.  Also see “Hip Ridge” for additional info.

Ridge Tile:  A roof tile used to cover the ridge.

Roof to Wall Flashing:  This is a continuous flashing that protects the intersection between a wall and a roofing surface.

Soffit:  The underside finished surface of the eave area.  I will use the term “eave” where a horizontal overhang is left open with the underside of the roof sheathing still visible.  I’ll use “Soffit” where the overhang has been enclosed by any type of trim material, either wood, stucco, aluminum, or any other type of material.   A Soffit is parallel to the ground.

Sheathing:  Roof sheathing is what is most commonly referred to as “the plywood that covers the roof”.  Actually, plywood is no longer commonly used as roof sheathing material except at an exposed eave situation, where it is more attractive than OSB.  Oriented Strand Board (OSB) has taken the place of plywood and is easily identified by its mottled appearance. 

Step Flashing:  Multiple-piece “L” shaped flashing that is woven in with the courses of roofing material.  Typically, step flashing pieces are 2 inches longer than the roof course exposure and are installed with the roofing materials, one course at a time.  Your Home Inspector will look closely at the roof sheathing for water stains, signs that the roofing underlayment or a nearby flashing has failed.

Underlayment:  A water shedding membrane installed over the roof sheathing.  Sometimes referred to as roofing felt.  Common weights are 30 lb, 40 lb, 60 ob, and 90 lb.

Valley:  The down-sloping internal angle at the intersection of 2 sloping roofs.  As opposed to “Hip Ridge”.

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To contact Britt for your Phoenix Home Inspection, call 602-339-0615.

Phoenix Home Inspector    Phoenix Home Inspection    Phoenix Home Inspections   Phoenix Home Inspector Britt Dollmeyer at Spotlight Home Inspection, InterNACHI Home Inspector

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