Editorial Feature

Vinyl Siding and Accessories

Although at times considered only an option for residential exterior cladding, vinyl siding is growing in use for a wide variety of light commercial buildings as well. These include assisted living facilities, apartment buildings and office parks. This article covers more about the design possibilities of today's certified vinyl siding, as well as the performance, environmental and maintenance considerations to take into account when specifying vinyl siding and exterior accessories.


Today, vinyl siding can be found on the exteriors of homes, apartment buildings, assisted living facilities, office parks and other buildings across the country. Vinyl siding and accessories provide many of the traditional or modern looks that today's designers are trying to achieve on building exteriors. Over the past 35 years, vinyl siding has increased in popularity because of its durability, ease of maintenance, versatility and low installed cost. Currently, vinyl siding holds about 50 percent of the market share for exterior cladding products on residential and light commercial buildings.

Vinyl siding can be found in a wide range of styles including:

  • Clapboard
  • Dutchlap/Shiplap
  • Beaded panels
  • Shake

The coordinating accessories available from most vinyl siding manufacturers include:

  • Fascia
  • Corner posts
  • Gable vents
  • Window and corner trim
  • Crown moulding
  • Shutters
  • Architectural accent panels
  • Gutters and downspouts
  • Scallops, diamonds, etc.

Vinyl siding and accessories also can be manufactured in a wide range of finishes and textures - such as horizontal or vertical wood grains - or in a smooth matte finish. These finishes and textures are incorporated into the product during the manufacturing process, so the look is crisp and consistent. Vinyl siding also can be formulated with variegated colours in a variety of shades, similar to stained wood.


Vinyl siding was first produced in the early 1960s through a process known as profile extrusion. This process was difficult to run at high speeds and to control the final shape, but in the late 1960s a process known as post forming improved vinyl siding manufacturing. In the 1970s and 1980s, the industry made numerous improvements in formulation which have allowed the product to be produced faster, weather better, resist impact, and allow a larger range of colours.

With these improvements, vinyl siding volume grew quickly during the late 1970s and surpassed the volume of aluminium siding in the early 1980s. The advantages of a lower cost material and easy installation have made vinyl siding the single largest residential siding material today.

Design Considerations

Product Characteristics

A standard vinyl siding panel has three main components:

  • A nail hem at the top of the panel where nailing slots are located.
  • The face, which is the area of the siding that will be visible once the installation is complete.
  • The buttlock, located on the bottom edge of the panel, which locks onto the previously installed panel.

The panels interlock to create an aesthetically pleasing and durable exterior for a home or building. When installed correctly, vinyl siding systems protect the structure of a building from the elements and water penetration. Accessories such as J-channels, corner posts and soffit are aesthetic, functional or both, hiding seams, providing an architectural accent to the siding or enclosing eaves or overhangs. Vinyl siding panels are manufactured in a range of lengths and widths. The average panel length is 12' to 12-1/2', but some panels can range from 14' to 16' or can even be as long as 40'. The typical width of panels is between 6-1/2" to 10".

Although many architects and specifiers think of vinyl siding as an option only in residential projects, it can actually be incorporated into a wide variety of light commercial and institutional designs as well. Assisted living facilities, retail buildings, churches, schools, libraries and office parks striving for a residential "feel" are a perfect fit for vinyl siding and accessories.

Colour and Finish

Today's vinyl siding is available in a multitude of colors with many embossed surface textures. Architectural scallops, shutters and detailed accessories such as corner posts and fascia are also available to coordinate easily with any design. Vinyl siding can be used to create a classic colonial style or a post-modern look, and virtually anything in between.

Today's vinyl siding products have lifetime warranties backed by more than 35 years of outdoor exposure. These guarantees are often transferable between owners of a home or building.

Fire Resistance

Since vinyl siding and accessories will melt when exposed to a significant source of flame or heat, home and building owners should take care to keep sources of fire - such as outdoor grills - and easily combustible materials - such as dry leaves, mulch and trash - away from vinyl siding. However, rigid vinyl siding has a relatively high ignition temperature (736 F) as compared to other materials like wood, cotton and other plastics. This means that even when exposed to an open flame source, vinyl will resist ignition much longer than most materials, which could serve to slow or even stop the spread of a fire.

If vinyl siding catches fire, it has a much lower flame spread rate than some comparable siding products - two and a half times lower than that of cedar siding and three times lower than hardboard siding. This relatively low flame spread rate slows the growth of a fire, allowing occupants more time to escape. Wall structures with installed vinyl siding have been tested according to the American Society for Testing and Materials (ASTM) standard ASTM E119 and found to have fire endurance ratings comparable to walls without vinyl siding installed. In other words, vinyl siding does not degrade the fire performance of a typical wall; in some fire situations, it could improve a wall's fire performance.

Technical data

The standard for technical performance of vinyl siding products is ASTM D3679, Standard Specification for Rigid Polyvinyl Chloride (PVC) Siding. This standard has established requirements and test methods for the materials, dimensions, warp, shrinkage, impact strength, expansion, appearance and windload resistance


Proper installation is critical to the appearance and long life of vinyl siding. Certainly, vinyl siding products may vary, but there are some general guidelines to follow for any vinyl siding installation job. A siding installer should always contact the siding manufacturer to determine whether there are specialized installation instructions for that product.

Because of vinyl's expansion and contraction properties, one of the key challenges during vinyl siding installation is to allow room for the siding to move in changing weather conditions. The following tips are important to keep in mind when installing vinyl siding.

  • When transporting and storing vinyl siding at a job site, be sure to keep the cartons dry, rest them on a flat surface and provide support for the entire length of the carton. Do not stack more than two boxes on top of one another.
  • Be sure that installed panels can move freely from side to side, allowing for expansion and contraction of the panel.
  • When installing a siding panel, push up from the bottom until the lock is fully engaged with the piece below it. Without stretching the panel, reach up and nail it in place.
  • Place nails or other fasteners in the centre of the nailing slot.
  • Do not force the panels up or down when fastening in position. Allow them to hang without strain.
  • Do not drive the head of the nail tightly against the siding nail hem. Allow 1/32" (about the thickness of a dime) clearance between the fastener head and the siding panel. Drive nails straight and level to prevent distortion and buckling of the panel.
  • Leave a minimum of 1/4" clearance at all openings and stops to allow for normal expansion and contraction. When installing in temperatures below 40 F, increase minimum clearance to 3/8".
  • Do not caulk the panels where they meet the receiver of inside corners, outside corners or J-trim. Do not caulk the overlap joints.
  • Do not face-nail or staple through siding. Vinyl siding expands and contracts with outside temperature changes. Face-nailing can result in ripples in the siding.
  • When re-siding, adding furring strips to a wall or removing uneven siding may be necessary.
  • In new construction (for the best aesthetics), avoid the use of green lumber as the underlayment. Keep in mind that siding can only be as straight and stable as what lies under it.


Nearly every architect, specifier and building professional faces the challenge of creating quality buildings or homes on a budget. Vinyl siding and accessories help meet the cost containment demands of the home or building owner. One recent study comparing vinyl siding to brick, aluminium siding and wood sidings in the residential market in terms of initial installed costs and 20-year maintenance costs found vinyl offered a cost savings of up to 60 percent compared to these alternatives. R.S. Means 1999 data indicate that the installed cost of vinyl siding is among the lowest of the various siding options.

Maintenance Requirements

Because colour is blended throughout the product during the manufacturing process, vinyl siding and accessories do not need to be painted or stained and will maintain a uniform colour throughout their life. The vinyl siding industry's efforts have been focused on minimizing colour change within the first two years after installation. Research has shown that change after that period is negligible.

From time to time, building managers and homeowners will need to wash their vinyl siding to eliminate dirt and dust, mould and mildew, grass and other stains. For tougher stains, vinyl siding can be cleaned with a soft cloth or soft-bristled brush (recommended for textured surfaces). Avoid abrasive cleaning products or cleaners containing organic solvents or other aggressive ingredients.

Selection and Specification Guidance

Relevant standards

Select and specify vinyl siding products comply with ASTM D3679, the accepted industry standard for quality.

ASTM D3679 Testing Requirements




Length and Width

Ensures siding meets the advertised length and width

Length: Average the length at three places on the siding
Width: Measure only what will be exposed once a piece is installed


Ensures siding meets the advertised thickness (and is a minimum of 0.035" thick)

Measure, in thousandths of inches, in five or more places on the siding


Ensures uniformity and accuracy of colour to manufacturers' specifications at the time siding is produced

Reflect light off a piece of siding as an instrument "reads" the colour


Ensures a consistent level of gloss on the siding, per manufacturers' specifications

Measure the reflection off several different pieces of the same brand


Measures the straightness of the siding

Lay siding flat against a straightedge and measure any difference; cannot be more than 1/8"

Heat Shrinkage

Measures the shrinkage that occurs after siding is extruded

Place in a hot air oven or water bath; should not shrink by more than 3 percent

Linear Expansion

Ensures siding will not buckle under extreme temperature changes

Freeze then heat a small piece of siding; measure expansion and contraction

Surface Distortion (also called "oil canning")

Ensures siding will not bulge, wave, or ripple in the heat

Heat a piece of siding on a wall to and inspect

Impact Resistance

Ensures siding will withstand nailing or cutting during installation

Drop an eight-pound weight on a piece of siding with a force equal to 60 inch-pounds; should not crack or tear at point of impact

Windload Resistance

Tests siding's ability to stay on the wall in heavy winds

Subject siding on a wall to low-grade hurricane winds (80 mph)

Weathering Performance

Ensures siding retains uniform colour over time without chipping, cracking, peeling, or flaking

Test pieces outside in various climates (dry/desert, cold/wet, and hot/humid) for two years

Manufacturing Process

Raw Materials

All vinyl products are made from a unique combination of vinyl resin and various additives that give these products their particular properties. For more information on the vinyl resin process, see the general vinyl section. Every formulation is different, and most are proprietary. Some of the additives commonly used in vinyl siding and accessories include:

  • Colourants, which determine the colour of the siding.
  • Ultraviolet (UV) protectants, which provide the siding with colourfastness even under daily direct sunlight.
  • Stabilizers, which help maintain the siding's rigidity.
  • Impact modifiers, which help keep the panels from denting or breaking under impacts such as hail.


Once the additives have been combined with the resin, the resulting material is called vinyl compound and is in pellet form. In the next stage of manufacturing, the compound is extruded, formed into various shapes and cut into various lengths. Most siding accessories are manufactured in much the same way, but are formed differently after leaving the die. As is the case with most vinyl products, vinyl siding and accessories are ground up and reused if the manufacturer determines them to be off-spec in any way, leaving very little resulting waste. Because vinyl is a thermoplastic, it can be reheated and reprocessed without loss of physical properties, except for UV stability. For this reason, manufacturers extrude vinyl siding with virgin topcoats and use recycled material in the substrates. In some cases, vinyl siding is co-extruded with a thin acrylic topcoat, which improves the product's weatherability. After extrusion, vinyl siding and accessories are inert and chemically stable. Colorants and other additives are bound within the material, and although outdoor exposure may cause changes over time, consistent performance will continue.

Environmental Considerations

Recyclability and Disposal Issues

Like all vinyl products, vinyl siding and accessories are recyclable, both pre-use (e.g., manufacturing off-cuttings and construction site waste) and post-use (e.g., removal at end of useful life). Pre-use vinyl siding scrap is often in prime condition for recycling, provided collection facilities are available that will minimize contamination from other materials.

Once siding scrap has been collected and transported to a recycling facility, it is typically ground into a flake form and put through a metal removal system. The flake material may also need to be washed before being sold to a scrap user. As is the case with off-cuttings or off-spec material from the manufacturing process, pre- or post-use vinyl siding can be reprocessed into new vinyl products with little or no loss of properties.

If recycling is not an option, and vinyl siding scrap must be landfilled, it can be trusted to remain safely inert under normal landfill conditions

Energy Efficiency

Vinyl siding is significantly lighter in weight than some alternative materials, such as brick or fibre cement, which saves energy and fuel in transportation.

Indoor/Outdoor Air Quality

Vinyl's ease of maintenance means no paints, stains or harsh chemical cleaners need to be used on vinyl siding.

Resource Conservation

Vinyl siding can directly replace wood-based products such as cedar siding. Vinyl siding and accessories are also durable products, which is increasingly being recognized as an advantage not only from an economic perspective, but also from an environmental one. The longer a product lasts, the less energy or other resources that must be used to maintain the product or manufacture replacement products and the less scrap that must be disposed of, not to mention the time and money saved by not having to maintain and replace building products.

Source: The Vinyl Institute

For more information on this source please visit The Vinyl Institute

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