External entry doors

The entry doors to your home are the main access points from outside. All homes have a front door, and this is usually the main entrance situated at the front of the building. If you have a secondary access point this is usually called the back door, and occasionally the side door if it's positioned at the side of a building. There is a huge choice of types and styles of door leaf which can be used for front or back doors. 

Both entry doors need to provide security and protection from the elements, so they need to share the same basic properties, even though they often look quite different to each other. The construction of your entry door, and the material it's made of, will affect the properties it has, and also the cost. Most front and back doors in your home will be operated with hinges. Pivot doors are a more unusual and modern option and sliding and folding doors are typically only used for patio doors.

Front doors

The front door of your home is vital for security and can be a key point of heat loss, but it's also an important feature. It is usually the way most visitors will enter the house, and often one of the first things people will notice. Choosing an appropriate type, style, and colour of door can complete the overall look of the outside of your home, improve the kerb appeal and even increase your home's value. 

Because front doors are usually a key visual point on your home, they are usually much more decorative than any other external door. They are more likely to have different hardware installed, such as letterboxes and door knockers.

Back doors 

The back or side door of your home is usually a secondary entrance. Occasionally they are used in conjunction with patio or French doors, and other times patio or French doors are used to replace them altogether. They are generally less visible than the front door, but they are still a key access point to your home. 

They are often a more plain design than the front door, as they are not usually the main entrance. But, some homes use the back door as a main entrance, and personal preferences may mean you want to choose a more unusual or decorative design. You may want a back door to match your front door, or you might prefer them to be completely different. Whatever you want, there should be a door for you.

How are entry doors constructed?

There are two basic ways an entry door can be constructed - traditional panel construction and composite construction. Both are made of individual pieces joined in a way that they form a solid slab. However, composite doors are often manufactured to look the same as panel doors, and high-quality doors like this will be almost indistinguishable from a wooden panel door. 

How are external panel doors constructed? 

External panel doors are constructed in the same way as internal panel doors. The main difference between these two types of door is the actual materials which each part is made from and how the doors should be treated and maintained. External panel doors should be much stronger, more durable, thicker, and heavier. 

Panel doors are a traditional frame and panel construction. There are lots of different styles of panel door available to choose from, with design differences including variations on the number of panels used, the shape of the panels and the way the panels are arranged.

The basic parts which make up a panel door are rails, stiles, and panels, and sometimes mullions. The rails are the horizontal pieces used to frame the panels. All panel doors have a top and bottom rail and two stiles, one either side. If there is more than one panel there might be additional rails and mullions which separate them. These frame pieces join with mortise and tenon or dowelled joints to produce a sturdy structure.  

The panels are held in grooves, or recesses, carved into the frame pieces. The edges of the panels are purposely made a little thinner than the groove they sit in so they 'float' within the frame. This allows natural expansion and contraction to occur without compromising the integrity of the door's structure. 

When glazing panels are used in a panel door they will need to be held in by glazing bars, special strips which hold glass in a frame, and can be separated with vertical strips, sometimes called muntins. These need to have appropriate weather seals and should have insulated glass - double- or triple-glazed - when used in external doors.  

For more information see: Glazed doors

Mouldings or trims can also be added around the edges of where the panels meet the frame pieces. These are raised strips with shaped profiles that add a decorative effect and enhance the look of the separate panels. 

How are external composite doors constructed?

If an external door is not a panel door it will have been constructed in a similar way to an internal flush door, with different materials being fixed together to form a solid panel. This method can provide superior properties over individual materials.  

The exact way an individual door is constructed will depend on what materials are being used and the manufacturer. Generally, the door leaf will be made from a frame with a face fixed to either side of it and a core filling which provides some insulation. Each part can be made from different materials, and more than one material can be used to form individual parts.

Additions to this basic construction include reinforcements within the frame or core, usually made of metal to improve the overall strength of the door. They may also have faces that are made with more than one layer. These can be to improve strength or insulation, or they may be mainly used to add a decorative finish to the completed door face.

What can entry doors be made of?

External doors need to have specific properties so they can withstand the conditions and regular use they are likely to face. Because of this, they are usually a mixture of different materials, each with specific benefits, to produce a solid construction which will perform at its optimum.

Check the specification of individual doors to see which material they combine, and what benefits those materials will provide. The quality of the individual materials used will probably be reflected in the price of the door, the manufacturer's reputation and any guarantees provided. If the door is glazed you'll want to take the properties of the glass being used into consideration. 

Both the panel door construction and the composite door construction usually use a mixture of materials to produce one door leaf. Panel doors sometimes have their individual pieces made up of a combination of materials, such as laminated or veneered timber pieces. 

MDF

Exterior grade MDF (medium-density fibreboard) can be used in the construction of external doors. This is often given a natural wood veneer which must be fixed with an exterior grade adhesive and runs the risk of peeling over time. This is usually an inexpensive option that should resist warping due to MDF being constructed from wooden fibres. 

MDF will need to be regularly maintained, and repainted every few years, especially if it is exposed. It's not considered to be as attractive as natural wood, but it's ideal for painting, and with a high-quality veneer it can look as elegant as solid wood. The MDF can also be moulded to resemble a traditional panel door.

The advantages and disadvantages of MDF

ADVANTAGES

DISADVANTAGES

• Usually cheaper than other materials

• Less tendency to expand or contract than natural woods, as long as it's sealed

• Easy to paint, or can come with a veneer or laminate attached

• Doesn't split easily

• Relatively strong - uUsually has enhanced performance 

• More sustainable than natural wood

• Relatively heavy

• If not sealed properly on all sides it will soak up any moisture and can swell, causing permanent damage

• Will shrink in environments with low humidity

• Can't be stained

• Doesn't hold screws as well as solid wood; fixing in screws can cause it to split

• It's not very attractive unless it has a quality finish applied

• Contains urea-formaldehyde which can be dangerous when sanding or cutting

Natural wood

Natural wood can be used for many of the different parts of external doors. Even if a door does not use solid pieces of wood it will often have a wooden veneer on the faces, to give it an elegant look. Woods is strong and long lasting, but only if it's regularly maintained and fully sealed on all edges. Different species have different properties - you'll need to check specifications to see what wood specific doors use.

The cost of an individual door which uses natural wood will differ greatly, depending on the quality of the wood, how it's used within the door's structure, and how much wood is used.

The advantages and disadvantages of natural wood 

ADVANTAGES

DISADVANTAGES

• Looks attractive 

• Expensive natural woods can be used as veneers and can easily be applied to other materials

• Can be stained or painted, and can come ready finished from the manufacturer

• Fairly good insulation properties

• Can be expensive

• Requires more maintenance than most other materials, and it must be repainted or restained every few years

• Can be prone to warping and rot if it does get wet

• Needs to be sealed on all edges

• There are large variations in the quality and durability of different woods - look for high-quality brands

uPVC 

Most uPVC doors are relatively inexpensive, but they can hold up relatively well against the weather and constant use. They require little maintenance and usually come ready assembled as a full door set, with hardware already attached. They are a popular choice and will match if you have uPVC windows, which are found in many modern homes. 

uPVC is usually used as a face material and can be moulded. uPVC doors often resemble panel doors, but they can be produced in an array of different designs. They come in white as standard but can be produced in other colours and with various finishes, but this might make them more expensive. 

The advantages and disadvantages of uPVC  

ADVANTAGES

DISADVANTAGES

• Usually one of the cheapest options

• Easy to maintain

• Good thermal insulation 

• Won't rot, peel or flake

• Changing door hardware will be difficult or even impossible

• uPVC will not last quite as long as most other materials

• Extreme temperature shifts can cause it to crack

• Not considered as attractive as wood

Steel 

Steel is an excellent choice for a door which needs to have security and durability as a priority. This heavy material can be used as a face material or within the door to give it added strength. Steel doors should be long lasting but relatively inexpensive. They need some maintenance, but not as much as wooden ones.

Steel doors have an insulated core, such as polyester or PU foam. This gives them good insulation properties. They usually come with all hardware already fitted, otherwise, this can be difficult to install. Steel can be painted or given a finish to resemble wood grain, although they are normally poor imitations and steel doors won't look as elegant as natural wood. 

The advantages and disadvantages of steel  

ADVANTAGES

DISADVANTAGES

• Won't warp, chip or crack

• Offers excellent protection against the elements and any rough treatment

• Steel doors will be durable and long lasting

• Available in many colours and finishes, which includes natural wood grain

• Can be relatively inexpensive

• Even when steel is finished it won't be as attractive as natural wood 

• It's very heavy and can be difficult to install

• Is difficult to fit with replacement hardware

• Needs to have an effective insulation core and steel surfaces will be subject to drastic temperature changes

• Can be prone to rust if it's scratched or chipped

• Will require some maintenance 

Aluminium 

Aluminium parts of doors will be strong and durable, but relatively lightweight. They naturally resist rust and so require minimum maintenance. Like steel, aluminium doors will have insulated cores, although the metal itself can be subject to extreme temperature changes. 

They probably won't look as attractive as wood but can be given a coating in a choice of colours. Aluminium won't be as strong and durable as steel, and can be prone to denting or weak weld joints. It's also usually more expensive than steel. Aluminium is often used as external cladding on wood to protect it. 

The advantages and disadvantages of aluminium  

ADVANTAGES

DISADVANTAGES

• Tough and durable

• Naturally rust resistant, and usually protected with an anodised finish

• Lighter than steel and fibreglass

• Available with various finishes

• Doesn't dent easily

• Won't look as elegant as natural wood

• Can be prone to denting, especially on corners

• Can have weak weld joints

• Can be expensive

Fibreglass 

Fibreglass, or GRP (glass reinforced plastic), can be used to form the faces of a door, usually moulded to look like a wooden panel door, or it can be used as an insulation material in a door's core. High-end fibreglass doors will be some of the most expensive doors, but they will have excellent durability and insulation properties, and can be given a wood grain finish which is indistinguishable from natural wood.

Less expensive fibreglass doors will not be as durable. Fibreglass is excellent at resisting weather and damage, although it can crack under severe impact. It requires very little maintenance and composite fibreglass doors are usually supplied ready assembled as a door set with hardware attached and fully finished.  

The advantages and disadvantages of fibreglass

ADVANTAGES

DISADVANTAGES

• Very durable and resists denting

• Resistant to moisture and won't peel, swell, or warp

• Requires very little maintenance

• Available in many different colours and with various finishes, including wood grain

• Excellent thermal insulation properties

• Can crack under severe impact and is very difficult to repair

• There is can be a big difference in the quality of individual fibreglass doors; high-quality fibreglass doors are expensive but more durable

• Cheaper versions are painted, rather than having the colour all the way through them; these show scratches - look for quality brands such as XL Joinery

Polystyrene cores

Polystyrene can be used within the core of a door to improve its insulation properties. This lightweight material keeps the weight of the door down, which should make it easier to install. Polystyrene offers no structural support and is not as effective as polyurethane.

The advantages and disadvantages of polystyrene

ADVANTAGES

DISADVANTAGES

• Relatively inexpensive

• Very lightweight

• Good insulation properties

• Can melt if it reaches very high temperatures 

• Offers no structural support

Polyurethane cores

Polyurethane, or PU foam, is used to provide a very high level of insulation. This is a lightweight material which is more expensive than polystyrene but will be much more effective This means it could save you money in the long run by reducing energy bills. These cores can be used with various face materials.   

The advantages and disadvantages of polyurethane

ADVANTAGES

DISADVANTAGES

• Excellent insulation properties

• Lightweight

• Won't absorb moisture

• Resistant to bugs, such as termites

• More durable than polystyrene

• Relatively expensive

• Its thermal properties will decrease slightly during the first few years after manufacturing