Vinyl siding is one of the most used building components available today. Especially in the US, vinyl siding is enormously popular due to its durability, cost-effectiveness, and ease of installation. 

Vinyl siding comes in a number of colors, styles, shapes, and prices. As such, it often finds its way onto luxury homes, starter homes, and everything in between. In most designs, the exterior trim used along with vinyl siding components is clad, or covered in a thin layer of aluminum.

In recent years, extruded PVC (polyvinyl chloride) has become popular due to its stability, maintenance-free surface, and ease of use. Today we will discuss exterior trim commonly found on a home with vinyl siding.

What Is Exterior Trim? 

Exterior trim, as part of a vinyl siding project, refers to the components that frame and seal the project as a whole. Exterior trim will usually form the outline where a change takes place, such as turning a corner, joining a roof, stopping, or connecting to another structure.

The broad category of trim, as applied to a home with vinyl siding, can include lumber clad with aluminum, or extruded trim, such as PVC, or other synthetic materials. There is virtually no limit to the design choices and possible combinations of exterior trim. 

Some traditional home designs, such as a colonial, may combine several smaller trim profiles into what appears to be a single unit. This allows nearly unlimited creativity for the designer and often makes a home exterior quite unique.


Fascia boards typically follow the horizontal edge of a roof. These boards are attached (usually every 24”) to the ends of the roof rafters, called rafter tails. These boards normally provide the connection and support point for gutters, and are often sized accordingly. For example, a standard residential gutter section will be about four inches in height, so a typical fascia board will be a 1” x 6” wide board. The additional couple of inches in width allows the gutter to be connected to the upper edge on one end and slope towards the downspout. Some larger homes with large roof areas require commercial style gutters to handle the additional flow of rainwater. In these situations, 1’ x 8’, or even 1’ x 10’ boards are common. Fascia boards must be structurally sound, as more often than not, they will support the weight of the gutters, plus the weight of the water.


Rake boards cap off the ends of a roof and usually attach to the fascia board on either end of a house. Rake boards will follow the edge of the roof similar to a fascia board, but rake boards are not horizontal. 

Rake boards will follow the roof line if the house has a gable structure. A home with a hip and valley roof design will usually not use rake boards. In contrast to a fascia board, a rake board usually only supports its own weight. Rake boards are often molded with a router to add distinctive shapes and profiles, because they are often a component of a home’s overall visual appeal.


Frieze boards are quite versatile, and can be incorporated into many areas of a home’s exterior. The most common location is just under the soffit, installed vertically on the wall. These boards often create a transition point, such as from vinyl siding to brick, or from vertical to horizontal.

Frieze boards are very common in home styles that incorporate elaborate trim, such as Victorian, or Georgian. Frieze boards are often considered decorative, but they also add elegance as well, especially when used in combination with other trim and mouldings, such as crown.

Casing and Brick Moulding

Casing and brick moulding are exterior trim pieces usually found surrounding entry doors, windows, and garage doors. Windows and doors are usually the first areas in a home to be damaged by water, because they interrupt the solid surface of the siding. 

Using low maintenance (usually extruded PVC) casing and brick moulding in these areas is very common. This trim typically frames doors and windows, but it can be used essentially anywhere, or in combination with other trim to create a unique appearance.


Decorative trim, as the name implies, is installed for its appearance. There are many different profiles available, but this category would often include quarter round, cove, shoe, crown, and many others.

These trim designs can be found in many maintenance free materials, such as PVC. Decorative trim is often small, so care should be taken during cutting to avoid shattering or melting.

What Is Exterior Trim Made From?

Cellular Polyvinyl Chloride (PVC)

Polyvinyl Chloride, better known as PVC, has emerged in recent years as a very low maintenance exterior trim option. PVC trim is made using the same materials and processes as the drain pipes in a typical home. The material is very durable, waterproof, and easy to work with.

One of the most popular locations for PVC trim is in the form of brick moulding. This is a unique trim most often found around entry doors and garage doors. PVC looks and works like wood and in combination with primer, can be painted. 

Compressed Wood and Resin

In recent years, products created from wood by-products have become popular due to their sustainable production. In the past, wood by-products created as a result of lumber processing were either destroyed or placed in a landfill.

These products repurpose the wood by-products by mixing it with resins and other chemicals to create a durable, stable trim. Important to note, these products must be sealed after exposing the raw fibers during cutting, as the fibers will absorb moisture. 

Polystyrene Foam

Foam trim products are inexpensive, durable, and easy to work with. Normally extruded from polystyrene or polyurethane, foam trim is more moisture resistant than wood trim, however, it is fairly brittle. Foam trim can be painted as well using latex based exterior paint.

Fiber Cement

Fiber cement trim is often associated with fiber cement siding, but it is also commonly found on homes with vinyl siding. These are most often used as a component of the trim design, as sparsely used individually.

Fiber-cement trim is made from small strands of fiberglass, combined with cement and other chemicals. Fiber cement trim resists rot and decay, remains stable over time, and is moderately priced. 

However, fiber cement trim must be sealed and painted. Installation of fiber cement trim also requires special techniques, and can be difficult to work with. Safety is paramount when working with fiber cement products as airborne fiberglass fibers are considered an irritant.

How Is Exterior Trim Installed?

The installation method will vary from material to material, so we will touch on the common methods and fasteners used for each material. The important thing to remember when installing any exterior trim is any fastener must be moisture resistant. This means any staple, nail, or screw used must be galvanized, stainless steel, aluminum, painted, or coated in other corrosion resistant materials.

Aluminum Clad

By far, the most commonly used method of helping a home shed water is cladding. Cladding refers to the process of using a machine, called a brake, to shape and mold sheets of aluminum, or other pliable metal. The material, known as trim coil, is made from thin aluminum and usually comes in a 24” x 50’ roll. Trim coil comes in a variety of colors and is usually installed using aluminum trim nails. Cladding is very common over most wooden components, such as fascia, rake, eaves, and window casing. Cladding can be retrofitted over features of older homes as well, such as porch posts.

Polyvinyl Chloride (PVC)

PVC trim is installed using the same methods and fasteners as wood. Again, the importance of using corrosion resistant fasteners is critical. Although the material itself will not absorb water nor rot, a regular steel fastener can rust and break over time, leading to water damage.

PVC is easy to work with and typically mills similarly to wood. PVC also resists splitting, as there is no grain for a crack to follow. PVC can also be primed and painted to match an existing decor.

Compressed Wood and Resin

Compressed wood and resin trim materials are usually installed very much like fiber cement boards. The preferred fastener is often a hot-dipped galvanized ring shank, or twist nail.

It is very important to follow the manufacturer’s installation directions when using compressed wood and resin trim, as the material can be easily damaged by water. These products usually come already primed, but care must be taken after installation to caulk and paint any raw material. This includes any deep scratches and countersunk nails.

Pro Tip. Most installers use a pneumatic nail gun, so care must be taken not to countersink the nails. Most manufacturers require nail heads to be flush to the surface, as countersinking exposes the fibers of the material to moisture and may void the warranty.


Foam trim is very easy to install as it is lightweight and flexible. However, foam is usually brittle, so it is often installed using galvanized brads or finish nails. These can be installed by hand, but most installers will use a pneumatic brad nailer or finish nailer. Because it is lightweight, sometimes foam trim is installed using an adhesive, but this method can make removal of the trim very difficult in the future.

Fiber Cement

Fiber cement trim is often installed using galvanized ring or twist nails, per the manufacturer’s instructions. The most common mistake first time installers make with fiber cement trim is assuming it does not require sealing.

Although the material is weather resistant and will not rot, it can absorb water. Therefore, great care must be taken to keep the material sealed with paint and caulk. This includes sealing any joints, countersunk nails, and providing the spacing between pieces as recommended by the manufacturer.

Choose the Right Exterior Trim For the Job

Installing exterior trim to compliment vinyl siding can make all the difference in appearance and functionality. The maintenance free nature of vinyl siding can be diminished by using the incorrect trim for the job.

Fortunately, there are many styles and options to choose from when shopping for external trim to compliment a vinyl siding project. If the goal is a maintenance free exterior, the smart move is to mix and match materials carefully and closely follow the installation directions. Doing so will ensure a durable, attractive exterior that compliments the appearance and functionality of vinyl siding.

Editorial Contributors
Matt Greenfield

Matt Greenfield

Matt Greenfield is an experienced writer specializing in home improvement topics. He has a passion for educating and empowering homeowners to make informed decisions about their properties. Matt's writing focuses on a range of topics, including windows, flooring, HVAC, and construction materials. With a background in construction and home renovation, Matt is well-versed in the latest trends and techniques in the industry. His articles offer practical advice and expert insights that help readers tackle their home improvement projects with confidence. Whether you're a DIY enthusiast or a seasoned professional, Matt's writing is sure to provide valuable guidance and inspiration.

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