What are composite front doors actually made of?

Composite doors are a popular choice for UK homeowners looking for a new front door, offering lasting strength, reliable security and excellent energy efficiency. That performance comes down to how they’re built, using a combination of different materials rather than one. But not all composite doors are built the same way, and what sits at the core makes a real difference. Here’s what’s inside a composite front door and why it matters, so you can make an informed decision about your new door.

Key takeaways

• A composite door is made from a foam or timber core, insulating layers, a GRP outer skin and a reinforced frame
• There are two types of timber core: standard solid timber and engineered timber, which is made from layers of wood bonded together
• An engineered timber core is less likely to warp, bend or swell over time
• Composite doors are low maintenance and last around 30 years

Inside a composite door

A foam or timber core

The core sits in the middle of the door and gives it its strength. There are three main types.

Foam-filled cores

A foam-filled composite door has a core of dense foam. It’s lighter than a timber-core door and helps keep heat in.

Standard solid timber cores

A standard solid timber core is made from sections of natural timber. It gives the door a reassuring weight and solid feel. However, because it’s natural wood, it can swell, shrink or move slightly as the weather gets warmer, colder, wetter or drier.

Engineered timber cores

An engineered timber core is made from layers of timber bonded together. This stops the wood moving as much, so the door is less likely to warp, bend or swell over time. You still get the strength, weight and solid feel of a timber-core door.

Comp Door, one of the leading composite door brands we install, is built around a 48mm cross-laminated core made from Albasia Falcata, a lightweight timber that holds its shape well. Cross-laminated means the layers are bonded with the grain running in different directions, so each layer holds the others in place.

Why we choose an engineered timber core

We believe an engineered timber core gives you the best of everything: a door that keeps its shape, feels strong and solid, helps keep your home warm and lasts for years. Because the core stays straight, the door keeps a tight seal against its frame, helping to keep draughts out year after year.

Insulating layers

Insulating layers slow down the heat passing through the door, helping stop the warmth inside your home escaping to the cold outside. This helps reduce heat loss and keep your energy bills down.

A GRP outer skin

The outer layer of our composite doors is made from glass reinforced plastic, known as a GRP skin. This tough, weatherproof surface protects the door from harsh weather conditions. It won’t rot or need repainting and can be finished with a realistic woodgrain effect, giving you the look of timber without the upkeep. Comp Door’s standard finish has a deep, traditional woodgrain, while its SleekSkin upgrade is lighter and silky smooth.

A reinforced frame

A reinforced frame keeps the door straight and gives the locks something solid to fix into, making it an essential part of your door’s security features.

Comp Door’s TriSeal frame is designed to seal tightly around the door, helping to keep wind and rain out. It comes in a choice of chamfered (angled) or sculptured (curved) styles. You can find out more in the Comp Door brochure.

How composite doors compare with uPVC and timber

Every type of door has something different to offer and the right one depends on your home and preference:

• Timber doors: solid wood brings natural character and warmth, making it a lovely choice for traditional homes. Regular painting or staining keeps it looking its best.
• uPVC doors: a uPVC door is made from a single material, making it lightweight, low maintenance and a good choice for many homes.
• Modern composite doors: combine the look of timber with the weather resistance and low upkeep of modern materials, in one strong, solid door.

Are composite doors secure?

Yes. Every Comp Door has a lock that secures itself automatically when the door closes, so you never have to worry about forgetting. The lock is designed to resist snapping, a method burglars often use. It also meets the latest UK security standards for extra peace of mind.

Kubu Smart Security is included with every Comp Door, with the option of sending alerts to your phone to show if your door is open, closed or locked.

How composite doors keep your home warm

A U-value shows how easily heat escapes through a door, so the lower the number, the warmer your home stays. Comp Door achieves a U-value of 1.4 W/m²K and is the first timber-core composite door to reach this figure.

That comes from every part of the door working together, including the engineered core, the TriSeal frame and the rest of the door. Because the core holds its shape, the door also keeps a tight seal over time.

For you, that means a warmer hallway, fewer draughts and lower energy bills through the colder months.

Caring for your composite door

Composite doors need minimal maintenance. Every few months, wipe the door down with a damp cloth and warm water, avoiding harsh chemicals that could damage the finish. Once or twice a year, lubricate the hinges and locks and check the seals around the frame.

Follow this simple routine and your door will enjoy a long lifespan of around 30 years.

Style and customisation options

Your front door is one of the first things people notice, so it plays a big part in your home’s kerb appeal. The Comp Door range offers a wide range of styles to suit traditional properties and modern homes, with:

• 18 colours that can be mixed and matched inside and out
• A choice of decorative glass designs to let natural light into your hallway
• Matching and glazed side panels
• Stable door and French door options
• Door hardware ranges, including marine-grade stainless steel with a lifetime guarantee

Browse our composite doors page for inspiration and start picturing your perfect new front door.

Talk to Emerald Windows and Doors

We have been fitting windows and doors across Swindon and the surrounding South West since 2004, including quality composite doors from our Comp Door range. If you’re thinking about a new composite door, our expert team can help you choose the right one for your home.

• Request a free quote online
• Call our team on 01793 700 142
• Visit our Swindon showroom to see our composite doors in person