June 25 2016 0Comment

Siding Terminology 101

Working with contractors can be scary. Especially if you don’t understand the terminology. We want to help. Here is a list of common terms in siding that you may hear as you discuss a project with a contractor. Keep in mind, if you are confused, don’t be afraid to ask for clarification. If a contractor is annoyed or side-steps the question, they may be trying to hide something. At Koalaty, we want to make sure you understand every step of the process.


Air Sealing– To spray low density foam where there is little to no insulation.

Anti-Microbial Spray– A solution; typically a quaternary ammonium salt, applied to building products to inhibit or kill potentially harmful microorganisms, such as certain types of mold.

Back Roll– To roll over a freshly spray painted surface with a roller.

Band Board– A decorative piece of trim placed between floors along the rim joist.

Blind Nailing– The action of placing a fastener through the top edge of lap siding to where it will be hidden by the next course of siding.

Bump Out– A built out protrusion from a building.

Butt Joint – To place materials end-to-end or edge-to-edge without overlapping.

Caulk– A compound used to fill cracks, gaps, seams, and joints.

Course– A row of planks, one plank wide running the length of the house. When assessing siding we number these course vertically from bottom to top, with the bottom course being 1.

Delamination– When the veneer of hardboard siding loses adhesion to the interior pulp product, allowing for moisture absorption and further degradation of the siding.

Dormer– A gabled extension built out from a sloping roof to accommodate  a vertical window.

Drip Cap– A molding or metal flashing placed on the exterior top side of a door or window frame to cause water to drip beyond the outside of the frame.

Drip Edge – A metal or vinyl flashing placed on the top edge of the roof sheathing which directs water away from the structure to prevent seepage under or behind fascia trim boards.

Eave– The lower part of the roof that projects over the exterior wall assembly.

Edge Checking– When the protective layer on the bottom edge of a Hardboard siding begins to crack or peel exposing the interior siding to elements.

Face– The side of the siding, trim, or soffit showing once the product has been installed.

Face Nailing– The action of placing a fastener through the face of the plank where it is visible.

Fascia Board– A trim board attached to the ends of the rafters.

Flashing – A thin flat metal positioned under/behind roofing, windows, doors, corner posts, etc., to keep draining water from entering the house.

Fiber Cement Siding– Cladding made from a mixture of cement and wood fibers, known for its durability, classic wood look, and durability, however few companies install it properly.

Frieze Board– A horizontal member connecting the top of the siding with the soffit.

Gable– A wall end, that is created when a roof line is pitched and sloped in two directions.

Hardboard Siding– Currently it is a cladding made from a mixture wax, resin, and wood pulp or wood chips. Historically, it has been known to be made with waste paper. In fact, International Paper owned Masonite corporation prior to the siding lawsuits …mind….BLOWN.

House Wrap– A building paper that protects building materials from exterior water penetration. Permeability is a critical factor when considering house wraps.

L-Flashing– Flashing installed before starter strip to protect interior wall from moisture when installing a siding product over another structure that protrudes from wall 1/4”-6”.

Masonry– In terms of the siding, this refers different  forms of stone exterior cladding.

Metal Siding– Cladding typically made from Aluminum or Steel, best used in cold climates.

OSB – Oriented Strand Board. A common type of exterior panel sheathing.

Paint Failure– Blistering, cracking, chalking, peeling, bleeding, loss of adhesion, etc., which leave the siding exposed to moisture. This is the most troublesome with Hardboard siding.

Permeability– A materials capability to allow water in VAPOR form to pass through. Not allowing your home to “breath” can lead to “sick home syndrome” (poor indoor air quality).

Post– A long sturdy piece of timber or metal used to support a overhanging structure.

Proper Slope– The angle at which a building material manages the flow of water as intended.

Seam Tape– Waterproof fabric installed where House Wrap overlaps or meets penetrations.

Sheathing– Sheets of plywood or OSB (typically) nailed to the outside face of studs, in order to provide a surface for the exterior siding to be installed.

Siding Class Action Lawsuits– Numerous manufacturers had to pay billions for Hardboard sidings manufactured between 1978-2007 because of extreme issues and product failures.

Sill Plate– A building member resting and normally attached to the foundation of a building, The Rim Joist sits on top of the Sill Plate.

Soffit– The underside of a building structure such as arch, balcony, or overhanging eaves.

Square– In construction terms it means both; straight (adj), and 100’ sq foot (noun).

Stage– To deliver, stack, or store materials and dumpster in a specific location.

Starter Strip– Accessory under first course of siding used to provide a consistent plank angle.

Stucco Siding– An exterior cladding made by coating wall surfaces with a fine plaster.

Sub-Fascia– Framing member attached to rafters used  to support or pad out the fascia.

Thermal Bridging – Area of a building which has a significantly higher heat transfer than the surrounding materials resulting in an overall reduction in thermal insulation of the building. The studs and joists are common culprits as sheathing is typically not properly insulated.

Thickness Swelling– When siding has expanded in size due to moisture absorption.

Three Sided Beam– The beam surrounding a porch ceiling, typically supported with posts.

Vinyl Siding– Cladding made from PVC, known for its ease of maintenance and affordability.

Wax Bleed– When Resins used to make hardboard siding water resistant migrate to the surface of the plank.

Wood Siding– Cladding made from wood, NOT to be confused with Hardboard siding. Wood is known for its beauty, but is susceptible to pests, woodpeckers, and is high maintenance.

Z-Flashing– Flashing bent in the shape of a “Z”. Used over window trim band boards, panel intersections, and other vertical structures. Areas with Z-Flashing should not be caulked.

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