How To Hang An Internal Door

Learning how to hang an internal door properly is one of those jobs that looks straightforward until you try it. In reality, achieving a clean fit, smooth swing and tight margins takes care, patience and the right approach. Get it right and the door will work flawlessly for years. Get it wrong and you will be dealing with sticking edges, uneven gaps and hinges that work loose.

This guide is written from a UK trade perspective, based on how experienced carpenters approach door hanging on site. It covers tools, preparation, fitting techniques, costs and compliance with relevant standards, so you can decide whether to tackle it yourself or bring in a professional.

What You Need Before You Start

Hanging an internal door is not just about screwing on hinges and lifting it into place. Preparation and accuracy are what make the difference.

Here is a practical checklist used by most joiners:

• Internal door, typically 35mm or 40mm thick
• Door lining or existing frame in good condition
• Three hinges for standard doors, two only for lightweight hollow doors
• Hinges sized correctly, usually 3 inch or 4 inch
• Wood screws, usually supplied with hinges
• Tape measure and combination square
• Sharp pencil or marking knife
• Chisels, ideally 12mm and 25mm
• Hammer or mallet
• Cordless drill and pilot bits
• Hand plane or electric planer
• Door wedge or packers
• Spirit level

Useful additional items include a straight edge, two stable trestles, clamps, eye protection, hearing protection and a dust mask. A portable work light helps when marking hinge recesses inside a dark hallway.

Check that chisels and plane irons are sharp before starting. A blunt cutting edge is harder to control and more likely to tear veneer or wander outside a marking line.

If you are also fitting hardware, you will want to review How to Fit a Door Handle and Latch in a UK Home Measure Backset, Drill Holes and Fix Common Alignment Problems as part of your planning.

Understanding Door Sizes and Standards in the UK

Internal doors in the UK follow fairly standard sizing, but older properties can vary significantly. Common door sizes include:

• 1981mm by 762mm, or 2 foot 6 inches
• 1981mm by 838mm, or 2 foot 9 inches
• 2040mm by 726mm for some modern builds

Door thickness is typically 35mm in standard homes. Fire doors are thicker, usually 44mm, and must comply with fire regulations.

Measure the opening at the top, middle and bottom. Then measure its height on both sides. Use the smallest measurements when selecting a door because an opening that appears rectangular may narrow by several millimetres near the floor or head.

Also measure both diagonals. Matching diagonal measurements suggest that the opening is square. If they differ, the frame may be out of square and the new door will need careful scribing or the lining may need correcting.

Do not assume that a nominal door size is the exact finished size. Manufacturing tolerances vary, and an old door may already have been altered. Measure the new door itself before marking any cuts.

For fire doors, installation must meet guidance under Approved Document B of the Building Regulations. You can review official guidance here: https://www.gov.uk/government/publications/fire-safety-approved-document-b

Approved Document B applies in England. Scotland, Wales and Northern Ireland have their own building standards and technical guidance. The required fire performance still depends on the building type, escape strategy and location of the opening.

Clearances are critical. A typical joinery tolerance is:

• 2mm gap at the top
• 2mm gap on each side
• 6mm to 10mm at the bottom depending on flooring

Too tight and the door will bind. Too loose and it will look poor and lose acoustic performance.

These dimensions are general joinery targets for ordinary internal doors. A fire door must follow the gap dimensions stated in its test evidence, installation instructions and door schedule. Side and head gaps are commonly within 2mm to 4mm, but the approved limits for the particular doorset take priority.

Determine Door Handing and Opening Direction

Decide how the door will open before marking hinges or drilling for a latch. Reversing the handing later may leave unwanted recesses and holes in the door.

Stand on the side where the door will open towards you. If the hinges will be on your left, this can be described as a left hand door. If the hinges will be on your right, it can be described as a right hand door.

Handing terminology is not used consistently by every manufacturer. To avoid mistakes when ordering a prepared doorset, state the hinge side and confirm whether the door opens towards or away from you. A simple sketch viewed from above is even clearer.

A plain door blank can normally be hung either way, provided its two faces are suitable and its internal construction allows the required trimming and hardware positions. A factory prepared door may have a defined hinge edge, lock block, glazing orientation or fire label that determines its handing.

Think about furniture, light switches and circulation through the room. A door should not cover a light switch, strike a radiator or open directly into frequently used furniture. It should also have enough clear wall space to reach a practical opening angle.

Bedroom and living room doors commonly open into the room, keeping the landing or hallway clear. Bathroom layouts need extra thought. An inward opening bathroom door may obstruct access if someone falls behind it, while an outward opening door can obstruct a narrow landing. The safest arrangement depends on the available space.

Doors on escape routes may have specific opening requirements, particularly in non domestic buildings or rooms intended for larger numbers of occupants. Check the approved fire strategy or building control requirements rather than changing their direction without advice.

Choosing the Right Hinges

The hinge type directly affects how the door operates and how long it lasts.

Most internal doors use butt hinges. Heavier doors, particularly fire doors, require ball bearing hinges for durability and compliance.

For a full breakdown, see Door Hinge Types Explained.

As a rule:

• Use three hinges for solid core doors
• Use CE marked hinges for fire doors
• Match hinge finish to other ironmongery

Hinge positioning is usually:

• Top hinge 150mm to 180mm from the top
• Bottom hinge 200mm to 250mm from the bottom
• Third hinge centred between the two

Some manufacturers specify the third hinge closer to the top hinge because this area carries a significant proportion of the load. Always use the positions stated in the door instructions where they differ from general site practice.

Check hinge load ratings against the actual door weight, not just its size. Dense solid timber, glazed and acoustic doors can be much heavier than they look. Hinges also need the correct width so the knuckle clears the door stop and decorative mouldings.

Hinge Screws and Pilot Holes

The short screws supplied with basic hinges are not always suitable for a heavy door or an older frame. Standard internal hinges commonly accept number 8 or number 10 countersunk screws, roughly equivalent to 4mm or 5mm diameter.

A 30mm or 35mm screw is usually suitable for fixing into sound timber. One longer screw through the top hinge and into structural timber can help support a heavy door, but first check for concealed pipes and electrical cables. Do not use an excessively long screw where the frame fixing arrangement is unknown.

The screw head must sit fully within the countersink. A proud head can strike the opposite hinge leaf and prevent the door from closing. Select steel screws compatible with the hinge finish and with any fire performance requirements.

Pilot hole size depends on timber density and screw diameter. For a 4mm screw, a pilot of about 2mm to 2.5mm is generally suitable in softwood. Around 2.5mm to 3mm is often better in hardwood. The pilot should be close to the root diameter of the screw, rather than the full outside thread diameter.

Drill straight and to slightly less than the screw length. A piece of tape around the drill bit makes a useful depth marker. Keep each pilot centred in the hinge hole because an off centre screw can pull the hinge out of position as it tightens.

Drive screws firmly but do not overtighten them. Power drivers can strip soft timber quickly. Finish by hand if necessary, particularly with brass screws, which are softer and more likely to shear.

Fire Door Certification and Compatible Components

A fire door is a tested assembly, not simply a thicker door leaf. Its leaf, frame, hinges, closer, latch, glazing, seals and fixing method must work together to achieve the stated rating.

Common ratings include FD30 and FD60, intended to provide at least 30 or 60 minutes of fire resistance under the relevant test conditions. Evidence may refer to testing under BS 476 Part 22 or BS EN 1634 Part 1. Follow the documentation supplied with the specific product.

Do not remove, plane away or paint over identification labels and plugs. They help establish the door specification and may be needed during inspection. If trimming would remove a label, stop and consult the supplier.

Hinges for a fire door must have suitable fire test evidence and sufficient load capacity. The number, size, material and fixing screws should match the door certificate or installation instructions. Three hinges are normally used, although the approved specification remains the deciding factor.

Some fire door assemblies require intumescent hinge pads beneath the hinge leaves. These pads expand under heat and help protect the hinge recess. Fit them to the leaf, frame or both sides exactly as shown in the manufacturer documentation.

Do not assume that pads are optional, or that every fire hinge requires the same type. Their thickness can affect the recess depth and door gap. Use products included within the test evidence rather than substituting unverified materials.

Intumescent strips and smoke seals also need to remain continuous and undamaged. Do not cut through them unnecessarily, cover them with thick paint or replace them with a different size without checking compatibility.

For work in flats, houses in multiple occupation, communal areas or protected escape routes, a competent fire door installer is usually the sensible choice. The completed installation may need inspection records, certification and evidence that all components are compatible.

How To Hang An Internal Door Step by Step

Step 1. Check and Prepare the Door Opening

Start with the frame. If the lining is out of square or twisted, the door will never sit properly. Use a spirit level to check plumb and head level.

Small deviations can be worked around by adjusting margins, but anything significant needs correcting first.

Check that the lining is firmly fixed and that joints at the head are sound. Tighten loose fixings and repair damaged timber before fitting a new door. Hinges fixed into split or decayed wood will soon work loose.

Remove paint lumps, old screws and projecting nails. If existing hinge recesses are in the wrong positions, splice them with matching timber rather than filling deep recesses with ordinary decorator filler.

Place a long straight edge against both jambs to check for bows. Sight across the frame to identify twist. A lining can be plumb on each side yet still be twisted, causing the door to touch one stop while standing proud of the other.

Step 2. Offer Up the Door and Mark for Trimming

Stand the door in the opening using packers underneath. This sets your bottom gap accurately, especially if flooring is already installed.

Mark where the door needs trimming. Always take equal amounts off each side where possible to keep the panel layout balanced.

Plane gradually and test the fit often. Removing too much is irreversible.

Mark the top of the door and hinge edge clearly in pencil. This avoids turning the door around during repeated fitting. If the finished floor has not been laid, add its full thickness, including underlay and adhesive where applicable, before setting the bottom clearance.

Manufacturer Trimming Limits

Check the door label, packaging and installation sheet before using a saw or plane. The permitted trimming allowance varies considerably between products. Exceeding it can expose the core, weaken hardware fixings and invalidate the warranty or fire certification.

Hollow core doors have narrow solid timber lippings around a lightweight internal core. Depending on the product, the allowance may be only about 3mm to 6mm from each long edge and around 6mm to 12mm from the top or bottom. Some doors permit less. Never assume the lipping is deep enough for a large cut.

Factory veneered doors also need conservative trimming. A manufacturer may allow only a few millimetres from each edge. Excessive removal can spoil the visual balance, cut through the hardwood lipping or cause the veneer to break away.

Solid timber doors often offer more scope for alteration, but wide cuts can still disturb joints and panel proportions. Remove material evenly where practical and follow any limits supplied with engineered timber doors.

Fire doors have strict trimming allowances set by their certification. Many permit only minor adjustment to specified lipped edges. Some must not be trimmed at the top, particularly where the identification label is located. Never reduce a fire door to fit a substantially undersized opening without written confirmation from the manufacturer.

If the required reduction exceeds the allowance, buy the correct size door or alter the opening properly. Adding a thin strip back onto an over trimmed door is rarely an acceptable repair and is not suitable as an improvised solution for a certified fire door.

Safe Door Support and Planer Use

Doors are awkward and can cause serious injury if they slip. Lay the door flat across two stable trestles and clamp it securely. Support the full width so the door cannot rock or flex while you work.

For edge planing, secure the door vertically in a purpose made door stand or between padded supports. Do not balance it against a wall or hold it between your knees. Keep hands and feet away from the lower edge when lifting or repositioning it.

Before planing, inspect the edge for screws, staples and nails. Metal can damage a planer blade and throw fragments. Remove hardware and mark any concealed fixing positions.

With a hand plane, work with the grain wherever possible. Plane from each end towards the centre to reduce breakout at the corners. A small chamfer on the exit corner also helps protect veneer and lippings.

Set an electric planer to a shallow cut, usually well under 1mm for finishing passes. Hold it with both hands, allow the cutter to reach full speed and keep the base flat. Start with pressure on the front shoe, then transfer pressure towards the rear shoe as the tool leaves the edge.

Disconnect the planer before adjusting its depth, clearing waste or checking the blades. Keep the cable away from the cutting path and use a suitable residual current device where required. Wear eye and hearing protection, and control dust with extraction and a suitable mask.

Long edges should usually have a slight closing bevel on the latch side. This gives the leading edge clearance as the door swings past the frame. The bevel should be subtle and consistent, not a visibly angled cut.

Seal Every Trimmed Edge

Bare timber and exposed lippings absorb moisture more readily than factory finished faces. Seal all trimmed edges promptly, including the top and bottom, even if they will not be visible after hanging.

Use the coating specified by the manufacturer. This may be primer, paint, clear varnish or another compatible sealer. Apply enough coats to create continuous coverage, paying close attention to end grain.

Veneered doors should be sealed without flooding the face or leaving ridges. Remove dust first and follow the finish manufacturer's drying times.

Fire doors must be sealed in accordance with their instructions. The coating must not interfere with intumescent seals, certification labels or hardware. Sealing a cut edge does not make excessive trimming compliant, so remain within the stated allowance.

Step 3. Mark Out the Hinges

Lay the door flat. Measure and mark hinge positions as outlined earlier. Use a square to ensure lines are accurate across the edge.

Place the hinge on the edge and mark around it carefully.

Keep the hinge knuckle square and parallel with the door face. Mark with a sharp knife for the cleanest line, but avoid cutting beyond the hinge corners because these marks may remain visible after finishing.

Use the same reference edge for every measurement. Measuring one hinge from the top and another from the bottom can introduce errors if the door length changes during fitting.

Step 4. Cut the Hinge Recesses

This is where precision matters. Use a sharp chisel to score around the hinge outline first. Then remove material gradually to the thickness of the hinge leaf.

Depth should be exact so the hinge sits flush. Too deep and the door will bind against the frame. Too shallow and the hinge will hold the door proud.

Many professionals use a router with a hinge jig for speed and accuracy, especially on multiple doors.

When using a chisel, keep the bevel towards the waste for the perimeter cuts. Make several shallow cuts rather than trying to remove the full depth at once. Check the recess with the actual hinge, not a guessed measurement.

A router needs a sound template, the correct guide bush and a securely clamped workpiece. Test the depth on scrap timber first. Stop the router fully before lifting it from the recess.

Step 5. Fix Hinges to the Door

Drill pilot holes to prevent splitting, then screw hinges into place. Always secure with at least one full length screw initially, then check alignment before fixing the rest.

Confirm that each hinge leaf lies flat without rocking. Clear any chips beneath it and check that no screw head stands proud. Fit all screws once the hinges are aligned, using the pilot hole guidance above.

Step 6. Transfer Hinge Positions to the Frame

Offer the door back into the opening, supported by wedges. Mark hinge positions onto the frame.

Remove the door and cut recesses in the frame in the same way as before.

Use rigid packers at the bottom and temporary 2mm packers at the head to hold the correct margin. Mark the precise top and bottom of each hinge leaf. Do not rely only on measurements because small differences can cause the hinges to bind.

Step 7. Hang the Door

This part is easier with two people. Hold the door in position and fix screws through the hinges into the frame.

Start with one screw per hinge so adjustments can still be made.

A door lifter or broad wedge allows fine height adjustment without putting fingers beneath the leaf. Support the latch side until each hinge has at least one secure screw. Do not let the full door weight hang from a single partly driven screw.

Once the initial swing has been checked, add the remaining screws. Tighten them evenly and recheck the head gap because pulling one hinge hard into its recess can alter the alignment.

Step 8. Test and Adjust

Open and close the door several times. Look for:

• Even gaps around all edges
• Smooth operation without rubbing
• Door staying in position when left ajar

If it catches or drops slightly, adjustments may be needed. For detailed corrections, see How to Rehang a Dropped Internal Door in a UK Home Plane the Edge Adjust Hinges and Stop It Catching.

Test the door before fitting the latch because latch pressure can hide a swing problem. Open it to several positions. A correctly aligned door should not move rapidly towards the open or closed position under its own weight.

Adjustments for Specific Gap and Swing Problems

If the top latch corner catches the frame, the door may have dropped. Tighten the top hinge screws first. Replace stripped or ineffective screws with suitable longer screws into sound timber, provided the area has been checked for concealed services.

A damaged screw hole can be repaired with a glued hardwood plug, then redrilled after the adhesive has cured. Filling the hole with loose matchsticks is less reliable for a heavy door.

If the door rubs evenly along the latch edge, confirm that the hinge screws are tight and the frame has not moved. Plane the edge only if there is enough trimming allowance and the existing gap cannot be corrected through hinge adjustment.

If the gap is too wide at the latch side and tight at the hinge side, thin purpose made hinge packers can move the door slightly across the opening. Fit consistent packers behind the appropriate hinge leaves and make sure the screws still obtain a strong fixing.

If the hinge edge binds as the door closes, inspect for proud screw heads, excessively deep recesses or a hinge knuckle positioned too far into the opening. The hinge leaves should close freely without pressing against each other or crushing the frame.

If the door sits proud of the stops, close it gently and observe where it touches first. A twisted lining may contact the top on one side and the bottom on the other. Moving or refitting the stops can correct a minor issue, but a badly twisted lining should be reset.

If the door springs open, the hinge jamb may be out of plumb or the hinge recesses may be misaligned. If it swings shut by itself, the frame may lean towards the closing side. Minor movement is sometimes acceptable, but a strong swing needs the lining or hinge positions corrected.

If the door catches only at the bottom after carpet has been fitted, check that the hinges have not dropped before trimming. Allow enough clearance for the thickest part of the floor covering and any threshold, but avoid creating an excessive gap that harms privacy and sound reduction.

If the head gap is tapered, the frame may be out of square. A small taper can sometimes be disguised through careful fitting, while keeping enough timber at every point. A significant taper is better corrected at the lining rather than copied onto a new door.

Make one adjustment at a time and retest. Changing several hinges and planing an edge together makes it difficult to identify which action solved or worsened the problem.

Step 9. Fit Handles, Latches and Finishing Details

Once the door swings correctly, you can install ironmongery and architrave if required.

For a clean finish around the frame, refer to How to Fit Architrave Around a Door Frame for a Clean Professional Finish.

Position the latch where it is comfortable to use and visually appropriate for the door design. Confirm that a hollow core door has a suitable lock block before drilling. Manufacturers often mark the lock side on the top edge.

Fit the keep only after the door has settled correctly on its hinges. Align it so the latch enters without lifting or pulling the door. The door should meet the stops evenly without needing force from the handle.

Typical Costs in the UK

Costs vary depending on location, door type and whether the frame needs work.

Item	Typical Cost Range
Standard internal door	£40 to £150
Solid core or premium door	£120 to £300
Fire door	£120 to £400
Hinges and ironmongery	£15 to £60
Labour per door	£70 to £150

In London and the South East, labour often sits at the higher end. If trimming, frame adjustments or lining replacement are needed, costs increase.

A full installation of several doors is often priced per set, with discounts for multiple doors in one job.

Detailed DIY Costs

If you already own a drill, chisels, square and plane, a basic DIY installation may cost little more than the door and ironmongery. If you are starting without suitable tools, the saving can reduce quickly.

DIY Item	Typical Cost Range
Basic chisels and sharpening equipment	£25 to £80
Hand plane	£25 to £90
Electric planer	£50 to £160
Drill bits, screws, wedges and packers	£15 to £45
Trestles, clamps and safety equipment	£50 to £160
Router and hinge jig if purchased	£140 to £450

A homeowner buying a modest set of reusable tools might spend £120 to £300 before purchasing the door. A router and professional hinge jig are rarely economical for one door, although tool hire may be available for around £25 to £60 per day, plus deposits and cutters.

DIY costs should also allow for primer or sealer, replacement screws and waste disposal. If an incorrectly trimmed door has to be replaced, another £40 to £300 may be added to the project.

Detailed Professional Costs

A carpenter may charge a minimum visit fee, particularly for a single door. This commonly falls between £120 and £220, depending on location and the work involved. Labour becomes more economical per door when several openings are ready during the same visit.

Professional Work	Typical Cost Range
Hang one standard door in a sound existing frame	£90 to £180
Hang several standard doors, labour per door	£70 to £150
Fit handles and a standard tubular latch	£25 to £60 per door
Repair a damaged lining or old hinge positions	£60 to £180
Supply and fit a replacement door lining	£250 to £600
Supply and install a compliant fire doorset	£500 to £1,200 or more

Decorating is often excluded from a carpenter's fitting price. Priming, filling, sanding and applying finish coats may add £100 to £250 per door where a decorator is brought in separately.

A complete fire doorset can cost more where it requires a closer, certified glazing, smoke seals, intumescent protection, upgraded framing or formal inspection records. Communal and commercial installations may also involve access controls and specialist ironmongery.

Ask each tradesperson whether their quote includes collection, trimming, hardware fitting, frame repairs, sealing cut edges, waste removal and VAT. Comparing the same scope prevents a low initial quote from becoming more expensive through additions.

How Long Does It Take

An experienced carpenter will usually allow:

• 1 to 2 hours per door for straightforward fitting
• 2 to 4 hours if trimming and adjustments are needed
• Longer for fire doors or older properties with uneven frames

DIY attempts often take significantly longer, especially on the first door.

Allow extra time for finishes to dry before rehanging a sealed door. If the lining needs to be replaced, the work may extend across a full day because the new frame must be fixed, packed, checked and finished with architrave.

Common Mistakes to Avoid

These are the issues most often seen on jobs where doors have been fitted poorly.

• Cutting hinge recesses too deep, causing the door to bind
• Incorrect gap sizes, especially at the top and latch side
• Failing to use packers when positioning the door
• Over planing one side, leading to uneven panel spacing
• Using the wrong hinge type for the door weight
• Not checking the frame for square before starting

Another common problem is using incorrect screws. Cheap screws can shear or strip, leading to loose hinges over time.

Other avoidable mistakes include trimming before checking the floor finish, failing to seal the bottom edge, placing hinges over weak repairs and cutting into the lock block on the wrong side.

Do not use the door latch to pull a poorly fitted door against its stops. This places unnecessary strain on the latch, handles and hinge screws. Correct the fit first, then align the keep.

What Can Go Wrong

Even small errors can create ongoing frustration.

A twisted frame can cause the door to spring open or shut on its own. Misaligned hinges lead to doors dropping over time. If the bottom clearance is too tight, new carpets can prevent the door opening fully.

Fire doors installed incorrectly can fail compliance, which has serious implications for safety and insurance. The Health and Safety Executive provides guidance on safe building practices here: https://www.hse.gov.uk/construction/

If you are unsure, this is one of those jobs where hiring a skilled tradesperson can save time, materials and frustration.

Veneer breakout is another expensive problem. It often occurs where a saw or planer leaves an unsupported edge. Sharp tools, shallow cuts and working towards the centre reduce the risk.

A door can also appear correct immediately after installation and bind later as indoor humidity changes. Properly sealing all edges and leaving consistent margins reduces seasonal movement, although solid timber doors may still move slightly.

Should You DIY or Hire a Professional

If you are confident with tools and have patience, a single door is a reasonable DIY project. Multiple doors, older properties or fire rated installations are better handled by a professional carpenter.

Professionals bring experience in dealing with uneven openings, selecting correct ironmongery and achieving consistent finishes across multiple doors.

DIY is most suitable where the existing frame is square, the replacement door is close to the required size and no certified fire performance is involved. You should be comfortable making accurate cuts, supporting a heavy item and using sharp hand or power tools safely.

The financial case for DIY is strongest when you already own the tools and can reuse them. If you need to purchase a plane, clamps, trestles, drill bits and safety equipment for one door, professional labour may cost little more than the new equipment.

There is also a risk cost. Removing too much material, damaging veneer or placing a hinge recess incorrectly can mean replacing the leaf. A carpenter's labour includes experience that reduces this risk and usually produces a faster, more consistent result.

Hiring a professional is sensible where the opening is twisted, the door is expensive, several matching doors are being fitted or the lining requires structural repair. Heavy glazed, acoustic and solid core doors are difficult to handle safely without assistance.

Fire doors deserve a separate assessment. Their installation affects life safety and may be inspected by building control, a fire risk assessor, a landlord or a managing agent. A competent installer should understand the product evidence, permitted trimming, closer forces, seal arrangements and required records.

Before accepting a quotation, ask whether the carpenter has experience with your door type and whether remedial frame work is included. For fire doors, request evidence of suitable competence and confirmation that the specified components will be used.

FAQ

How much gap should there be around an internal door?

The standard gap is about 2mm at the top and sides, and 6mm to 10mm at the bottom depending on flooring. Consistency matters more than exact measurement, as uneven gaps are noticeable.

For a fire door, follow the certified gap requirements rather than relying on general dimensions. Smoke control doors may need a suitable threshold seal where the bottom gap would otherwise be too large.

Can I hang a door on my own?

It is possible, but awkward. Internal doors are heavier than expected and holding them steady while fixing hinges is difficult alone. Most tradespeople work in pairs for efficiency and accuracy.

If working alone, use a proper door lifter, rigid packers and stable supports. Never place fingers underneath an unsupported door or attempt to balance it while driving screws.

Do I need three hinges on an internal door?

For most modern doors, yes. Three hinges help distribute weight evenly and reduce the risk of the door dropping over time. Two hinges are only suitable for very lightweight hollow doors.

Always check the door and hinge manufacturer's requirements. Heavy, glazed, acoustic and fire doors need hinges selected by load rating and test evidence rather than appearance alone.

What is the best way to trim a door?

A sharp hand plane or electric planer is typically used. Always remove small amounts and test fit frequently. Seal any cut edges, especially on veneered or fire rated doors, to protect against moisture.

A circular saw with a fine blade and clamped guide may be suitable for a larger straight reduction, but only where the manufacturer's trimming allowance permits it. Score veneered faces and support the cut to reduce breakout.

How do I know which side the hinges should go on?

Stand on the side where the door will open towards you. Hinges on the left give a left hand arrangement, while hinges on the right give a right hand arrangement. Confirm this with a sketch when ordering because suppliers may use different terminology.

Can I trim the top of a fire door?

Only if the product documentation specifically permits it and the cut stays within the stated allowance. Many fire doors restrict top trimming because of labels, lippings or tested construction. If the instructions are unavailable, contact the manufacturer before cutting.

What size pilot hole should I drill for hinge screws?

For a typical 4mm screw, use about 2mm to 2.5mm in softwood and 2.5mm to 3mm in hardwood. Test on similar timber if possible. The hole should guide the screw while leaving enough material for the threads to grip.

Why does my door swing open by itself?

The hinge jamb may be out of plumb, the lining may be twisted or the hinge recesses may not align. Check the frame with a spirit level and inspect where the door meets the stops. A strong unwanted swing usually needs frame or hinge correction rather than extra latch pressure.

Do internal doors need to meet building regulations?

Standard internal doors do not usually require approval. Fire doors must comply with Building Regulations, particularly in properties with multiple storeys or where they form part of a protected escape route.

Alterations can also affect accessibility, ventilation and escape arrangements. If a door is part of approved building work or a managed fire strategy, confirm the requirements before changing its size, direction or specification.

Final Thoughts

Hanging an internal door properly is all about precision, not speed. Taking time to measure, mark and adjust carefully is what separates a professional finish from a frustrating result. While many homeowners can manage a single door, consistency across multiple rooms and compliance with fire safety rules often calls for experienced hands.

If you want the job done right the first time, you can post a job on BookaBuilderUK to receive quotes from vetted local tradespeople who handle door installations every day.