Painting a door properly is not difficult, but it is unforgiving. A door is a large flat surface at eye level, viewed in raking light, opened and touched every day. Every brush mark, every run and every missed edge is visible for years. The difference between a good result and a poor one is almost entirely in the preparation and the sequence, not in the paint.
This guide covers painting a front door and painting internal primed doors, the two jobs most UK homeowners face. It uses UK products, UK terminology and UK weather. We supply over 80 internal white primed doors and over 80 unfinished internal doors that all need finishing on site, plus over 90 external doors, so this is a job our customers do constantly.
Before You Start: Why Sealing a Door Matters
Paint Is Protection, Not Just Colour
On an external timber door the paint film is the only thing keeping moisture out of the timber. Water in the core causes swelling, the door binds in the frame, joints open, and the finish fails. Colour is the by-product. Protection is the job.
All Six Faces Must Be Sealed
Front, back, both long edges, the top edge and the bottom edge. The top and bottom edges are the ones people miss, and they are where moisture enters most easily because they are end grain. An unsealed top edge will wick water into the door over a single winter.
Manufacturer Guarantees Depend On It
Most door guarantees are conditional. They typically require the door to be acclimatised, to be finished within a stated period of delivery, and to have every face and edge sealed. If a door fails and the top edge is bare, the guarantee will not help you. Read the paperwork that came with the door.
Acclimatise the Door First
Lay the door flat in the room where it will hang, off the floor on battens, for at least 48 hours before you do anything to it. A door taken from a cold van and painted the same afternoon will move.
Never Paint Over a Fire Door Label
Fire doors carry a certification label or plug, usually on the top edge. Painting over or removing it can invalidate the certification. Our over 240 fire doors all carry this marking, and our guide to fire door materials explains why it matters.
Choosing a Colour for a Front Door
Look at the House, Not the Colour Chart
The brick, the render, the roof tiles and the window frames are all fixed. The door has to work with them. Take the colour chart outside and hold it against the actual wall in daylight.
Traditional Choices That Rarely Fail
Dark blue, forest green, black, oxblood red and heritage grey. These work on almost every UK housing type from Victorian terrace to 1930s semi.
Bold Choices and Where They Work
Yellow, teal and coral can look excellent on a small terrace or a period cottage and look wrong on a large modern house. The bolder the colour, the more the surroundings have to support it.
Check Any Local Restrictions
Conservation areas, listed buildings and some leasehold or estate agreements restrict external colours. Check before you buy the paint, not after.
Test It Properly
Paint a test board, not a patch on the door. Move the board around through the day. A colour that looks right at midday can look completely different in evening light.
Dark Colours Absorb Heat
A very dark door in full south facing sun gets hot. On a composite or a modern timber door that is usually fine, but check the manufacturer guidance before applying a very dark colour to a door that was not supplied in one. We list 18 composite external doors, most of which are factory coloured and should not be repainted.
Choosing the Right Paint
Water Based Paint
Modern water based exterior paints are flexible, quick drying and stay white rather than yellowing. They are now the default for most UK exterior joinery. Two topcoats minimum, always.
Oil Based Paint
Traditional oil based gloss gives a very hard, high shine finish and flows out beautifully, but it takes far longer to dry, smells strongly and yellows over time in low light. Still the right choice for some period restorations.
A Note on Terminology
You will see American guides refer to latex paint and enamel paint. In the UK the equivalents are water based emulsion or acrylic for the former and oil based gloss or eggshell for the latter. Do not use interior emulsion on a door: it has no durability and no water resistance.
Primer
Primer bonds to the substrate and gives the topcoat something to grip. Bare timber needs a wood primer. Knots need knotting solution first, or the resin will bleed through and stain the finish. A factory primed door already has this layer, which is the whole point of buying one.
Undercoat
Undercoat builds the film and evens out the colour underneath. On a strong colour change it saves you a topcoat. It is not optional on bare timber.
Matching System
Use primer, undercoat and topcoat from the same manufacturer and the same system. Mixing an oil based undercoat under a water based topcoat is a common cause of peeling.
How Much Paint You Need
A standard 1981mm x 762mm door has roughly 1.5 square metres per face, so about 3 square metres for both faces plus edges. Most exterior paints cover 12 to 16 square metres per litre per coat. A one litre tin will therefore give you two coats on both faces of a single door with a little to spare. Buy one tin for one door, and buy it all at once so the batch matches.
Choosing the Sheen Level
Gloss
The most durable and the easiest to wipe clean, and the traditional choice for a front door. It also shows every imperfection in the surface underneath, so it demands the best preparation.
Satin
A mid sheen. Forgiving of minor surface flaws, still wipeable, and currently the most popular finish for both internal and external doors in the UK.
Eggshell
A low sheen with a soft look. Excellent on internal doors and on period external joinery where a full gloss would look wrong.
Matt
Avoid on doors. Matt finishes mark easily and cannot be cleaned without burnishing.
Matching Existing Joinery
If the skirting and architrave are satin, a gloss door will look out of place. We list 16 skirting products and 16 door architraves, and our guide to door architraves covers fitting them.
Preparing the Door
Take the Door Off If You Can
Painting a door flat on trestles gives a far better finish than painting it hanging. Gravity works with you instead of against you, and you can reach the edges. Take the hinges off, mark which is which, and lay the door on two trestles.
Remove the Hardware
Take off the handle, the letterplate, the knocker, the numerals and the escutcheons. Masking round hardware never looks as good as removing it. We stock over 2,500 door handles and over 2,900 door hardware lines if you decide to replace rather than refit.
Clean Before You Sand
Wash the door with sugar soap or a mild detergent solution and rinse it. Sanding a dirty door just grinds the dirt into the surface.
Deal With Failed Paint
Scrape back any flaking or blistered paint to a sound edge. Feather the edges of the sound paint so the repair does not show as a ridge. If more than about a third of the surface has failed, strip the whole door.
Fill and Repair
Fill splits, dents and old screw holes with an exterior grade wood filler on a front door, or a fine surface filler internally. Let it cure fully, then sand flush.
Sanding
Work through the grades. Start at around 120 grit if you have repairs to level, then finish at 180 to 240 grit. Always sand along the grain. Cross grain scratches show through gloss paint permanently.
Key the Surface
An existing sound gloss finish needs to be dulled all over so the new coat can grip. If the surface still shines after sanding, you have not keyed it enough.
Dust Off
Vacuum the door, then wipe with a tack cloth or a barely damp lint free cloth. Dust is the single most common cause of a gritty finish.
Do Not Sand a Fire Door Face
Aggressive sanding on a fire door face can compromise the certified construction. Clean and key lightly only, and follow the manufacturer instructions.
Priming and Undercoating
Knotting Solution First
On bare softwood, seal every visible knot with knotting solution and let it dry. Skipping this is why so many painted doors develop brown circles after a year.
Applying Primer
One thin, even coat. Primer is not meant to build thickness. Get it into the end grain on the top and bottom edges especially.
Applying Undercoat
One or two coats depending on the colour change. Lightly sand between coats with 240 grit and dust off.
Factory Primed Doors Still Need Undercoat
A factory primed door has a base coat, not a finish. It still needs at least two topcoats, and a light denib sand before the first one.
Do Not Skip Straight to Topcoat
Topcoat over bare timber will soak in unevenly, look patchy and fail early.
Painting the Door: The Correct Sequence
Work From the Top Down
Start at the top and work down. Any runs or drips fall onto wet paint you are about to work into, rather than onto a finished surface you cannot fix. This is the opposite of what some guides suggest, and it is the standard decorating practice for a reason.
Order for a Panelled Door
Paint the mouldings around the panels first, then the panels themselves, then the horizontal rails, then the vertical stiles last. Following that order keeps the final brush strokes running the length of the outer frame, which is what the eye reads.
Order for a Flush Door
Divide the face into imaginary sections, work top to bottom, and keep a wet edge across the whole width. Do not stop halfway.
Lay Off Along the Grain
Load the brush, spread the paint across the section, then finish with light strokes along the grain without reloading. This is what removes brush marks.
Keep a Wet Edge
Never let the edge of a painted section dry before you join the next one to it. If you have to stop, stop at a natural break such as a rail or a moulding line.
Thin Coats, Not Thick
Two thin coats beat one thick coat every time. Thick paint sags, wrinkles and takes days to harden.
Do Not Overwork the Paint
Modern water based paints start to set quickly. Going back over an area that has begun to skin will tear the film. Lay it off once and leave it.
Brush or Roller
A good synthetic brush for water based paint, a natural bristle brush for oil based. A short pile foam roller on the flat panels followed by laying off with a brush gives a very even result on a flush door.
Do the Edges
Hinge edge, lock edge, top edge and bottom edge. On an external door these are the most important surfaces on the whole job.
Drying Time Between Coats
Follow the tin, and add time in cold or humid conditions. Recoating too early traps solvent and gives a soft finish that marks for months.
Painting Conditions
Temperature
Most exterior paints need above 8 to 10 degrees Celsius, and the temperature must stay there while the paint dries, including overnight. Painting a front door in November afternoon sunshine and leaving it out in a frost will ruin the finish.
Humidity and Rain
Do not paint an external door if rain is forecast within the drying window. High humidity dramatically slows water based paint.
Direct Sunlight
Avoid painting in strong direct sun. The surface skins before the paint has flowed out, which locks in brush marks.
Security While the Door Is Off
If you remove a front door, plan the job so it goes back the same day. Never leave a house open overnight.
Dust and Insects
Work in a clean, still space. Wet gloss outdoors in summer collects insects, and picking them out ruins the finish.
Painting Internal Primed Doors
Why Primed Doors Are Worth Buying
A primed door saves you the messiest stage of the job and gives a factory flat base. It costs less than a fully finished door and lets you choose any colour. Our range starts at £30.84 for the LPD White Primed Flush Internal Door, with the LPD Ladder Smooth Internal White Primed Door at £70.45, the LPD Textured Vertical 5 Panel Internal White Primed Door at £79.35, the LPD Vancouver Primed White Internal Door at £82.50, the Deanta Flush White Primed Door at £105.00, the LPD London Primed White Internal Door at £111.75, the Deanta Windsor White Primed Internal Door at £150.75 and the LPD Dover White Primed Internal Door at £216.00.
Paint Before Hanging
Finish the door flat before it goes on its hinges. It is quicker, cleaner and you can seal the top and bottom edges properly.
Denib the Primer
Factory primer has a slight texture. A light pass with 240 grit and a dust off before the first topcoat makes a visible difference.
Two Topcoats Minimum
One coat over primer will look thin and will not wear. Two coats is the minimum, three if you are going from white primer to a deep colour.
Seal the Edges Before Hanging
Even internally, the top and bottom edges should be sealed to keep the door dimensionally stable. This is a guarantee condition on most ranges.
Fully Finished as an Alternative
If you would rather not paint at all, we list over 350 fully finished internal doors, including over 60 internal grey doors. Our grey internal doors guide covers those options, and the pre-finished, unfinished and primed doors guide compares the three routes directly.
Choosing the Finish
Our guide to door finishes and the complete guide to internal door finishes go into lacquer, oil, wax and paint in more detail.
Rehanging and Adjusting the Door
Let the Paint Harden First
Touch dry is not hard. Most paints need several days to cure properly. Rehanging too early leaves the paint marked by the hinge leaves and stuck to the frame.
Check the Fit
Several coats of paint add measurable thickness. A door that fitted tightly before painting may bind afterwards. If it does, our guide on how to plane a door covers taking it back safely.
Hinges
Refit the hinges in the original positions. We list over 350 door hinges and over 50 fire rated hinges, and our guide on where to fit door hinges covers positioning.
Stop the Door Sticking to the Frame
Fresh paint on a door and fresh paint on a frame will bond to each other if the door is closed too soon. Leave the door ajar for as long as you can.
Refit the Hardware
Refit the handle, letterplate and numerals once the paint is properly hard.
Weather Seals and Draught Proofing
Draught Proofing Is Not Painting
Sealing gaps around an external door reduces heat loss, but it is a separate job from finishing the timber. Do not treat one as a substitute for the other.
Compression Seals
A brush or rubber compression seal fitted into the frame rebate is the usual solution around the sides and head of an external door.
Threshold and Bottom Seals
A draught excluder at the base handles the largest single gap. Get the height right or the door will drag.
Do Not Caulk the Door Shut
Some guides recommend running sealant along gaps around the door. Never apply sealant to the gaps between a door leaf and its frame. Sealant belongs between the frame and the wall, not between moving parts.
Never Test a Draught With a Naked Flame
Testing airflow with a lit candle or an incense stick near a door is sometimes suggested online. Do not do it. Use the back of a wet hand, or a smoke pencil designed for the purpose.
Intumescent and Smoke Seals Are Different
On a fire door, the seals in the frame are intumescent, not draught seals, and they must not be painted over or replaced with anything else. We list 11 intumescent strips and pads.
Cleaning and Caring for a Painted Door
Routine Cleaning
Warm water and a little mild detergent on a soft cloth, twice a year on a front door and as needed internally. Rinse and dry.
What Not to Use
No solvents, no bleach, no abrasive creams, no scouring pads, and never a scraper or a blade on a painted surface. Any of these will cut through the paint film and open the timber to moisture.
Mould and Green Growth
North facing doors collect green algae. Wash it off with a fungicidal wash intended for exterior paintwork, following the product instructions, then rinse.
Inspect the Bottom Edge Annually
The bottom edge takes the worst of the splash back from the step. Lift the door off once a year or two, check the finish, and touch it up.
Deal With Chips Immediately
A chip in an external door lets water into the timber. Sand back, spot prime and touch in as soon as you see one.
Keep the Gutter and Canopy in Order
Most premature front door paint failure is caused by water running onto the door from a blocked gutter or a missing canopy, not by the paint itself.
Protect the Handle Area
The area around a handle takes the most contact. A fingerplate or a kick plate is a cheap way to protect it on a busy internal door.
Internal Doors and Pets
Paint is the least scratch resistant finish there is. If a dog scratches at doors, our guide on stopping a dog scratching a door covers the practical fixes.
How Often to Repaint
External Doors
A well prepared exterior finish on a sheltered door typically lasts four to eight years. An exposed south or west facing door with no canopy may need attention every three years.
Internal Doors
Ten years or more is normal. Internal doors usually get repainted because of a colour change rather than because the finish has failed.
Signs It Is Time
Chalking when you rub the surface, loss of sheen, hairline cracking, any bare timber showing, and any softness in the timber at the bottom rail.
Full Repaint or Touch Up
Touch up small chips as they happen. Once more than a small proportion of the surface has failed, a full repaint gives a better and longer lasting result.
When to Replace Instead
If joints have opened, the bottom rail is soft, or the door has warped, painting will not fix it. We list over 90 external doors, over 30 glazed external doors and 18 composite external doors.
Troubleshooting Common Paint Problems
Runs and Sags
Caused by too much paint in one coat. If it is still wet, brush it out. If it has dried, let it harden fully, sand flat and recoat.
Brush Marks
Caused by paint that is setting too fast, overworking, or a poor brush. Work in cooler conditions, lay off once, and use a brush matched to the paint type.
Blistering
Moisture trapped under the film, or painting in hot sun. Strip the blistered area back to sound material, find the moisture source, and repaint.
Peeling and Flaking
Poor adhesion. Usually a surface that was not cleaned or keyed, or incompatible paint systems. Strip and start again with a single matched system.
Cracking and Crazing
A hard coat over a softer one, or coats applied too thickly. Sand back and rebuild with thin coats.
Knots Bleeding Through
Knotting solution was not used. Sand back to the knot, apply knotting solution, then reprime and repaint that area.
Yellowing
Common with oil based whites in rooms with little natural light. Switch to a water based system.
A Gritty Finish
Dust, either on the door or in the tin. Sand smooth, clean thoroughly, decant paint through a strainer and recoat.
The Door Now Sticks
Paint build up. Identify the contact point with a strip of paper, then ease it back carefully.
Buying Doors and Hardware from Doors2Floors
Primed and Unfinished Doors
over 80 internal white primed doors from £30.84 and over 80 unfinished internal doors from £92.25.
External Doors
over 90 external doors, including oak options such as the LPD Norfolk Oak External Door at £434.75 and the LPD Cottage Glazed External Oak Door at £459.92.
Hardware
over 2,500 door handles, over 40 door knobs, over 720 locks and latches and over 30 door stops.
Frames, Architrave and Skirting
over 30 internal frames, 2 external frames, 16 door architraves and 16 skirting products.
Advice
Doors2Floors has supplied doors and flooring to homes and businesses across the UK. If you are unsure whether to paint or replace, contact our team. You can also read more about us, see the brands we carry, check delivery options or ask about a bespoke size.
Frequently Asked Questions About Painting Doors
How many coats of paint does a door need?
Over a factory primer, two topcoats minimum. On bare timber, knotting, primer, undercoat and two topcoats.
Should I paint a door in place or take it off?
Take it off if you can. Painting flat gives a better finish and lets you seal the top and bottom edges.
Do I need to prime a factory primed door?
No. Denib it lightly with fine abrasive, dust off, and go straight to topcoat.
Can I paint a composite front door?
Usually not. Composite doors are factory coloured and painting them can void the guarantee. Check with the manufacturer first.
Can I paint a fire door?
The faces can normally be decorated, but do not paint over the certification label, the intumescent seals or the door edges beyond what the manufacturer permits. Follow the manufacturer instructions.
What is the best paint for a front door in the UK?
A water based exterior wood paint from a recognised manufacturer, applied as a full system with matching primer and undercoat.
How long before I can close the door?
Leave it ajar for as long as practical, and at least until the paint is fully touch dry on both the door and the frame.
Do I need a sealer over the paint?
No. A modern exterior paint system is the protection. Adding a clear sealer over it is unnecessary and can cause adhesion problems.
What temperature is too cold to paint a door?
Below roughly 8 to 10 degrees Celsius, and remember the overnight temperature matters as much as the daytime one.
Can I paint over varnish or stain?
Only after thorough sanding to key the surface and an adhesion primer suitable for the substrate. Otherwise it will peel.
Why has my new paint gone patchy?
Usually uneven absorption from a missed or thin primer coat, or a single topcoat where two were needed.
How long does a painted front door last?
Typically four to eight years between repaints, depending on exposure, aspect and how well it was prepared.
This article is general guidance for UK homeowners. Always follow the instructions supplied with your paint and your door, and consult a qualified professional where fire safety, listed building consent or structural work is involved.