A new external door needs to fit, close properly and work well in everyday use. This requires more preparation than simply choosing a design and colour. Dimensions, opening direction, threshold, ironmongery and the connection to the façade must be clear in advance. The steps below will help you prepare carefully for installation.
First establish what is being replaced
An external door can mean just the door leaf, or the complete assembly of door, frame, threshold and ironmongery. This distinction affects site measurements, the work involved and the finishing. An existing frame must be checked to ensure it is straight, sound and technically suitable for a new door leaf. Wear, distortion or unsuitable dimensions may be reasons to replace the frame too.
Leg daarnaast vast welke onderdelen behouden blijven. Denk aan een bovenlicht, zijlicht, brievenbus, deurbeslag, huisnummer, deurbel of zonwering. Een onderdeel dat blijft zitten, kan de maatvoering of montagevolgorde beïnvloeden. Maak foto’s van de binnen- en buitenzijde en noteer zichtbare bijzonderheden voordat de deur wordt ingemeten.
Consider the function of the door
A front door has different requirements from a back door or a door to a utility room. At a frequently used entrance, comfortable access, ease of operation and a practical opening direction are important. For a garden door, its relationship with the patio and the available space may carry more weight.
Also decide how much daylight and privacy you want. Glazing in the door or a sidelight brightens an entrance, but its position and glass type need to suit how the space is used. Discuss ventilation requirements separately; leaving a door ajar is no substitute for planned ventilation provision.
Check the opening direction and clearance
The opening direction determines the positions of the hinges, handle and locking mechanism. The terms left and right can be confusing unless it is clear which side you are viewing from. Demonstrate the desired movement during the site measurement and have it recorded. Also check that the door will not hit a radiator, cupboard, wall, outdoor light or downpipe.
Check the area immediately inside and outside the door too. A doormat, a thick floor finish or a rising patio surface can obstruct its movement. An outward-opening door needs sufficient clear space outside, even if a planter or garden furniture is temporarily placed there.
Final dimensions require a professional site measurement
Measurements you take yourself are useful as an initial guide, but they are not automatically the dimensions to use for manufacture. A professional checks the opening at several points and assesses whether the jambs and threshold are level, plumb and square, as appropriate. The clearance needed for installation and connections to brickwork, façade cladding or render also matter.
Discuss any changes to the floor before the final dimensions are established. New tiles, underfloor heating, insulation or a different threshold can change the available height. If this work is to take place later, the finished floor level to be used as the reference must be clear.
Threshold and drainage
The bottom of an external door is exposed to rainwater, splashed dirt and heavy use. The threshold and junctions therefore need to suit the façade and the internal and external floor levels. External paving should drain water away from the home and must not block drainage openings. A low threshold may be desirable, but its design must be coordinated with weatherproofing, floor build-up and door construction.
Choose ironmongery and operating features
The lever handle, pull handle, lock cylinder, backplates and letter plate together determine how the door is used. Explain who will use the door and whether there are specific requirements for grip or operating height. If you want to retain an existing cylinder or keying system, compatibility with the new ironmongery must be established in advance.
Consider electronic components too. A smart doorbell, door opener, sensor or light may need wiring. Ideally, establish cable routes and connection points before installation starts. Agree their positions with the supplier or installer in advance so that seals and drainage are not pierced or obstructed.
Discuss the finishing work in advance
Removing an old door and frame can expose adjoining materials. It is therefore sensible to agree in advance what the installation includes and which internal or external finishing work will be needed afterwards. Consider plastering, timber trims, sealant joints, painting adjacent parts and making good around the floor.
Also check whether window dressings, a curtain, coat rack or alarm sensor need to be temporarily removed. This helps prevent damage and allows the installer to reach all fixing points. On the page about the methodology you can find more information about the steps from enquiry to installation.
Practical preparations for installation day
The doorway will be open for part of the work. Choose a day when someone can be present and keep pets and young children away from the work area. Clear enough space on both sides of the door. Remove loose items from the hallway and keep the route from the work van to the entrance clear.
Agree in advance where the old door leaf and any frame components can be placed. Also ask what will happen to the removed materials. If parking, loading or unloading is restricted at your property, let the installers know well before the appointment. A clear, short access route helps them move a heavy door unit safely.
Checklist for replacing your external door
- Specify whether only the door leaf or the frame as well will be replaced.
- Note which existing components need to be retained.
- Confirm the handing, opening direction and required clear opening.
- Mention any future changes to the flooring or paving.
- Choose the glazing, ironmongery, lock cylinder, letter plate and operating mechanism together.
- Discuss the threshold, drainage and junction with the façade.
- Agree on removal, disposal and internal and external finishing.
- Remove fragile items, window coverings and sensors near the work area.
- Provide a clear access route and enough working space.
- Browse completed projects in advance to compare details and door configurations.
Frequently asked questions
Can just the door leaf be replaced?
Yes, if the existing frame is straight, sound and suitable for the new door and the chosen ironmongery. If there is wear, distortion or poor junction detailing, replacing the complete unit may be a better option. A site measurement survey will clarify this.
How do I measure an external door myself?
Measure the opening in several places to get an initial idea and note the handing as well. Do not use these measurements as final manufacturing dimensions without having them checked. Any misalignment, installation clearances, the threshold and floor level need to be assessed on site.
Do I need to be at home during the installation?
Make sure an authorised contact person is available and preferably present. Questions about an existing detail or the finish may arise during the work. The installer also needs access to both the inside and outside.
What should I check after installation?
Open and close the door several times and check the operation of the handle, lock and any multipoint locking system. Inspect the junctions, sealant joints and finishes together. Ask which components need periodic cleaning or adjustment and keep the information about keys and ironmongery.
Discussing the installation of your new external door
Would you like to replace your external door? Read more about doors and installation. With your enquiry along with photos of the inside and outside, approximate dimensions and the required handing.