Roof windows and skylights both bring natural light into a room from above. As a result, the two terms are often used as though they mean exactly the same thing.
In everyday conversation, that is usually fine. However, when comparing products, requesting quotes or planning a loft conversion, the differences can matter.
A roof window normally sits within the slope of a pitched roof and can usually be opened. A skylight is a broader term that may describe almost any glazed opening in a roof, including fixed units, flat-roof rooflights, domes and basic non-opening glazing.
The best option depends on the roof type, room, budget and whether you need ventilation as well as daylight.
This guide compares roof windows and skylights in the UK, including their uses, installation requirements, costs, benefits and possible drawbacks.
Roof Window vs Skylight at a Glance
| Feature | Roof Window | Skylight |
|---|---|---|
| Typical roof type | Pitched roof | Pitched or flat roof |
| Usually opens | Yes | May be fixed or opening |
| Installed in reach | Often | Not always |
| Outside view | Usually good | Depends on position and design |
| Ventilation | Common feature | Optional |
| Standard sizing | Often uses standard frame sizes | Wide range of shapes and custom sizes |
| Cleaning access | Often designed for internal cleaning | May require roof access |
| Common use | Loft bedrooms, offices and bathrooms | Extensions, hallways, kitchens and stairwells |
| Installation angle | Usually follows the roof pitch | May follow the roof or sit on a kerb |
| Typical cost | Moderate to high | Very wide range |
| Common examples | Centre-pivot and top-hung windows | Fixed rooflights, domes and lanterns |
Are Roof Windows and Skylights the Same Thing?
Not always.
The term skylight describes a glazed opening installed in or above a roof. It is therefore a broad category.
A roof window is generally a particular type of skylight designed to sit within the roof slope and operate more like a normal window.
This means that most roof windows could reasonably be described as skylights, but not every skylight is a roof window.
For example:
- An opening window fitted into a tiled loft roof is usually called a roof window.
- A fixed glass panel above a flat-roof extension is usually called a rooflight or skylight.
- A clear plastic dome on a commercial flat roof is a skylight, but not normally called a roof window.
- A glazed lantern above a kitchen extension is a rooflight or roof lantern.
- A small non-opening pane installed in an old outbuilding may be called a skylight.
Manufacturers and contractors sometimes use the terms differently, so the product description matters more than the label alone.
What Is a Roof Window?
A roof window is a framed glazed unit installed within the slope of a pitched roof.
It is generally designed to:
- Follow the angle of the roof
- Provide daylight
- Provide an outside view
- Open for ventilation
- Close with a weather seal
- Integrate with tiles or slates using flashing
- Allow cleaning from inside
- Meet thermal and safety requirements
Common roof window designs include:
- Centre-pivot
- Top-hung
- Side-hung
- Electric opening
- Solar-powered
- Conservation-style
- Fire escape windows
- Balcony-style roof windows
- Roof access windows
Popular brands include VELUX, Fakro, Keylite and RoofLITE+, although many other manufacturers supply roof windows in the UK.
What Is a Skylight?
Skylight is a general term for glazing that allows light through a roof.
A skylight may be:
- Fixed
- Opening
- Flat
- Domed
- Pyramidal
- Curved
- Walk-on
- Tubular
- Framed
- Frameless
- Manual
- Electric
- Installed on a kerb
- Fitted flush with the roof
Skylights can be used on pitched roofs, but the term is especially common for flat-roof glazing.
What Is a Rooflight?
Rooflight is another broad term used for roof glazing.
In the UK, it is often used for:
- Flat-roof windows
- Fixed glass rooflights
- Roof lanterns
- Conservation rooflights
- Commercial roof glazing
- Walk-on glass
- Large architectural glazing
The terms rooflight and skylight are frequently interchangeable.
Roof Window, Skylight and Rooflight Terminology
| Term | Typical Meaning in the UK |
| Roof window | Opening glazed unit installed within a pitched roof |
| Skylight | General term for roof glazing |
| Rooflight | Often used for fixed or flat-roof glazing |
| Flat-roof window | Manufactured glazed unit for a flat or low-pitched roof |
| Roof lantern | Raised glazed structure above a flat roof |
| Sun tunnel | Reflective tube that carries daylight into a room |
| Conservation rooflight | Low-profile unit designed for traditional properties |
These descriptions are not rigid legal definitions. Suppliers may use different wording for similar products.
Main Difference: Opening and Ventilation
One of the biggest practical differences is that roof windows usually open.
They may use:
- A top control bar
- A bottom handle
- A centre-pivot hinge
- A top-hung mechanism
- An electric motor
- A solar-powered motor
- A wall switch
- A remote control
- A rain sensor
A skylight may be completely fixed and designed only to admit light.
Opening roof window benefits
- Natural ventilation
- Removal of warm air
- Reduced condensation
- Cooling during summer
- Easier cleaning
- Potential emergency escape, where suitable
- Better connection with the outside
Fixed skylight benefits
- Fewer moving parts
- Often lower purchase cost
- Slimmer frame options
- Larger uninterrupted glass area
- Lower risk of mechanical failure
- Useful where the unit cannot be reached
A fixed skylight may be ideal above a stairwell or kitchen island where ventilation is already provided elsewhere.
Main Difference: Roof Type
Roof windows are mainly associated with pitched roofs.
They usually integrate with:
- Concrete tiles
- Clay tiles
- Plain tiles
- Natural slate
- Artificial slate
- Metal roofing
- Thatch using specialist details
Skylights can be fitted to both pitched and flat roofs.
Flat-roof skylights may sit on:
- A timber kerb
- An insulated upstand
- A proprietary base
- A raised structural opening
- A roof lantern kerb
The waterproofing system must connect securely to the skylight or rooflight base.
Pitched Roof Window vs Flat Roof Skylight
| Feature | Pitched Roof Window | Flat Roof Skylight |
| Position | Within roof slope | Usually on raised kerb or base |
| Typical opening | Centre-pivot or top-hung | Fixed, hinged or electric |
| Water drainage | Flashing directs water around frame | Membrane rises up kerb |
| Common roof covering | Tile or slate | Felt, EPDM, GRP or single-ply |
| Outside view | Usually good | Often mainly sky view |
| Internal lining | Angled reveal | Vertical lightwell |
| Access | May be within reach | Often overhead |
| Cleaning | Some designs rotate for cleaning | May need external access |
| Common room | Loft bedroom | Extension or kitchen |
Which Provides More Daylight?
Both can provide excellent daylight.
The result depends more on:
- Glazed area
- Position
- Orientation
- Roof pitch
- Room shape
- Internal lining
- Nearby buildings
- Trees
- Glass coatings
- Number of units
- Frame thickness
A roof window installed on a pitched roof can admit significantly more light than a normal vertical window of a similar size because it faces more of the sky.
A flat-roof skylight can also bring strong overhead light into an extension where side windows are limited.
Which Provides a Better View?
A roof window usually provides a better outside view.
This is especially true where it is:
- Installed low enough
- Top-hung
- Tall enough for the roof pitch
- Positioned in a bedroom or living space
- Not blocked by nearby buildings
A flat skylight generally provides a view of the sky rather than the garden or street.
This may be exactly what is wanted where privacy matters.
Roof Window View vs Skylight View
| Requirement | Better Option |
| View across the garden | Roof window |
| View while seated | Low-positioned roof window |
| Sky view above a kitchen | Flat skylight |
| Privacy from neighbours | High skylight |
| Uninterrupted outlook when open | Top-hung roof window |
| Daylight without overlooking | Fixed rooflight |
| Light in a central hallway | Skylight or sun tunnel |
Which Is Better for Ventilation?
An opening roof window is normally better where regular ventilation is needed.
Warm air rises, so opening glazing high in a room can help release heat and moisture.
This can be particularly useful in:
- Loft bedrooms
- Bathrooms
- Kitchens
- Home offices
- Converted attics
- Garden rooms
- Stairwells
Opening skylights are also available, especially for flat roofs. However, they generally cost more than fixed units.
Manual, Electric or Solar Opening?
| Opening Type | Best Suited To | Possible Drawback |
| Manual | Window within reach | Difficult for high installations |
| Electric | High or inaccessible window | Requires wiring and controls |
| Solar-powered | Retrofit or difficult wiring route | Battery and motor add cost |
| Fixed | Light only | No natural ventilation |
| Automatic rain-sensor | Bathrooms, kitchens and high rooms | More components to maintain |
Which Is Easier to Clean?
Many centre-pivot roof windows rotate so the outer pane can be cleaned from inside.
Top-hung windows may also have a cleaning position.
Fixed flat-roof skylights can be more difficult because the outside glass may only be accessible from the roof.
Factors affecting cleaning include:
- Roof height
- Roof pitch
- Opening design
- Self-cleaning glass
- Nearby trees
- Moss and debris
- Access equipment
- Walk-on or non-walk-on glazing
Never stand on a skylight unless it is specifically designed and certified as walk-on glazing.
Which Is Better for a Loft Conversion?
A roof window is usually the most practical choice for a loft conversion.
It can provide:
- Daylight
- Natural ventilation
- Outside views
- Opening control
- Compatibility with pitched roofing
- Emergency escape in some designs
- Blackout blind options
- Heat-control accessories
Roof windows can also be installed without creating a large dormer, which may reduce structural work and visual impact.
However, Building Regulations, planning restrictions and fire-safety requirements still need consideration.
Which Is Better for a Flat Roof Extension?
A flat-roof skylight or rooflight usually suits an extension better.
Common options include:
- Fixed flat glass rooflight
- Opening flat-roof window
- Roof lantern
- Pyramid rooflight
- Circular rooflight
- Modular roof glazing
- Walk-on glass
A large rooflight above a kitchen or dining area can bring daylight into the middle of the room, where patio doors and side windows may not reach.
Which Is Better for a Bathroom?
Both can work well.
Roof window advantages in a bathroom
- Opens for ventilation
- Can be fitted with moisture-resistant finish
- Offers a view where privacy allows
- Compatible blinds are available
- Often easy to operate
Fixed skylight advantages
- Provides privacy
- Brings in strong daylight
- Works above baths and showers where permitted
- Can suit a flat-roof bathroom extension
- Has fewer moving parts
An opening unit may reduce condensation, but mechanical extraction is usually still important.
Which Is Better for a Kitchen?
A kitchen can benefit from either option.
A roof window suits a pitched kitchen roof, while a flat skylight works well above an extension.
Consider:
- Ventilation
- Grease and steam
- Cleaning access
- Glare
- Position over worktops
- Electric opening
- Rain sensors
- Solar heat gain
- Blinds
An opening skylight above a kitchen island can help release heat, but it may be difficult to clean if installed very high.
Which Is Better for a Bedroom?
Roof windows are often the better option for bedrooms because they can provide ventilation and a meaningful outside view.
Useful features include:
- Blackout blinds
- Top-hung opening
- Noise-reduction glazing
- Heat-control shutters
- Solar operation
- Rain sensors
- Child locks
- Trickle ventilation
A fixed skylight may still suit a bedroom where another opening window provides ventilation and escape.
Which Is Better for a Hallway or Stairwell?
A fixed skylight may be the most practical option where access is difficult.
Benefits include:
- Strong overhead daylight
- No need for routine operation
- Reduced reliance on artificial lighting
- Privacy
- Simple appearance
An electric opening skylight can be useful where heat builds up at the top of the stairs.
Roof Window vs Skylight Costs in the UK
Costs vary according to size, brand, roof type, access and structural work.
The following figures provide broad budgeting ranges.
| Installation | Typical UK Cost |
| Small fixed pitched skylight | £700–£1,500 |
| Standard centre-pivot roof window | £900–£1,800 |
| Larger top-hung roof window | £1,300–£2,800 |
| Electric or solar roof window | £1,800–£3,500 |
| Fixed flat-roof skylight | £1,200–£3,000 |
| Opening flat-roof skylight | £2,000–£4,500 |
| Large frameless rooflight | £2,500–£6,000 |
| Small roof lantern | £3,000–£6,000 |
| Large roof lantern | £5,000–£12,000 or more |
| Custom architectural rooflight | £4,000–£15,000 or more |
| Replacement like-for-like roof window | £900–£2,000 |
| Scaffolding | £500–£1,500 or more |
| Internal plastering and making good | £300–£1,500 |
The final price can rise where rafters or joists need structural alteration.
Why Skylight Prices Vary So Much
The term skylight includes many different products.
A small fixed unit may cost relatively little, while a custom walk-on rooflight can cost several thousand pounds before installation.
Price factors include:
- Size
- Opening mechanism
- Glass specification
- Frame material
- Brand
- Roof type
- Access
- Structural trimming
- Flashing
- Kerb construction
- Waterproofing
- Internal finishing
- Electric controls
- Blinds
- Planning requirements
- Crane or lifting equipment
Purchase Cost vs Installed Cost
The product price is only one part of the project.
An installed quote may include:
- Window or skylight
- Flashing
- Insulated collar
- Roofing underlay
- Structural timber
- Roof tiles or slates
- Flat-roof membrane
- Kerb
- Internal lining
- Plastering
- Decoration
- Scaffolding
- Electrical wiring
- Waste removal
- Building control fees
A low product price does not necessarily mean a low total cost.
Roof Window vs Skylight Installation
Roof window installation
A typical pitched-roof installation may involve:
- Measuring the roof and rafters.
- Removing tiles or slates.
- Cutting or trimming the structural opening.
- Fitting supporting timbers.
- Installing the window frame.
- Connecting roofing underlay.
- Installing flashing.
- Reinstating tiles.
- Adding insulation.
- Forming the internal lining.
- Plastering and decorating.
Flat skylight installation
A typical flat-roof installation may involve:
- Choosing the position.
- Cutting the roof opening.
- Trimming roof joists.
- Building a kerb or upstand.
- Insulating the opening.
- Fitting the skylight base.
- Connecting felt, EPDM or GRP.
- Installing the glazing.
- Forming the internal lightwell.
- Plastering and decorating.
- Wiring controls where required.
Which Is Easier to Install?
A like-for-like roof window replacement is often simpler than installing a new skylight.
For a new opening, the complexity depends on:
- Rafter or joist layout
- Roof covering
- Roof pitch
- Window size
- Internal ceiling
- Structural loads
- Access
- Electrical work
A small roof window fitted between existing rafters may require less work than a large flat rooflight needing several joists to be altered.
Which Is More Likely to Leak?
Neither should leak when correctly specified and installed.
Leaks generally result from:
- Incorrect flashing
- Poor membrane detailing
- Damaged roof covering
- Failed seals
- Blocked drainage
- Low upstands
- Poor roof falls
- Incorrect pitch
- Movement
- Inadequate maintenance
A roof window may leak around flashing and nearby tiles. A flat skylight may leak where the roof membrane meets the kerb.
The quality of installation usually matters more than the product category.
Common Roof Window Leak Points
- Flashing corners
- Tiles above the frame
- Underlay collar
- Side channels
- Top flashing
- Worn opening seals
- Cracked glass
- Frame joints
- Blocked drainage
- Poor internal insulation
Common Skylight Leak Points
- Kerb corners
- Felt or EPDM upstands
- Glazing seals
- Fixing points
- Frame joints
- Roof membrane laps
- Standing water
- Blocked outlets
- Cracked domes
- Lantern ridge joints
Which Is Better for Energy Efficiency?
Both can provide good thermal performance when modern glazing and insulated installation details are used.
Factors include:
- Double or triple glazing
- Low-emissivity coating
- Argon gas
- Insulated frames
- Warm-edge spacers
- Correct insulation around the opening
- Airtight internal detailing
- Solar-control glass
- Blinds or shutters
A poorly insulated opening can lose heat even when the glass itself performs well.
Heat Loss and Solar Gain
Roof glazing receives more direct sky exposure than many vertical windows.
This can mean:
- Strong winter daylight
- Useful passive solar gain
- Summer overheating
- Glare
- Heat loss at night
- Condensation on poorly performing units
Larger is not always better.
South-facing roof glazing may need:
- Solar-control glass
- External shutters
- Heat-reducing blinds
- Smaller glazed area
- Opening ventilation
- Shading
Roof Window vs Skylight Energy Comparison
| Energy Factor | Roof Window | Skylight |
| Double glazing | Common | Common |
| Triple glazing | Available | Available |
| Opening ventilation | Usually available | Optional |
| Solar-control glass | Available | Available |
| Blackout blinds | Widely available | Depends on product |
| External shutters | Common on major brands | Less common |
| Insulated upstand | Not usually relevant in same way | Important on flat roofs |
| Risk of heat build-up | Moderate to high | Moderate to high |
| Airtight installation | Essential | Essential |
Which Is Better for Noise Reduction?
Both can be supplied with enhanced acoustic glazing.
Noise performance depends on:
- Glass thickness
- Laminated panes
- Pane spacing
- Frame seals
- Installation
- Roof insulation
- Rain impact
- External shutters
Rain can sound louder on overhead glass than on a vertical window.
Some homeowners enjoy the sound, while others may prefer acoustic glazing in bedrooms.
Which Is Safer?
Both product types should use suitable safety glazing.
Important considerations include:
- Laminated inner pane
- Toughened outer pane
- Fall protection
- Child restrictors
- Locking handles
- Guarding around low windows
- Walk-on certification
- Fire escape requirements
- Safe cleaning access
A normal skylight must never be treated as walk-on glass.
Can a Roof Window Be Used as a Fire Escape?
Some opening roof windows may form part of an escape strategy where they meet the relevant size, opening and position requirements.
However, not every roof window qualifies.
Factors include:
- Clear opening area
- Opening dimensions
- Height above the floor
- Roof access
- External escape route
- Building Regulations
- Storey height
- Local building control interpretation
A fixed skylight cannot provide an escape opening.
Planning Permission
Roof windows and skylights can often be installed under permitted development, but this depends on the property and design.
Additional permission may be needed where:
- The building is listed
- The property is in a conservation area
- The unit projects significantly above the roof
- The roof shape changes
- The skylight faces a sensitive elevation
- Privacy restrictions apply
- Planning conditions remove permitted development rights
- A roof terrace is created
- The installation forms part of a larger extension
A like-for-like replacement is generally simpler than creating a new opening.
Building Regulations
Building Regulations may apply where work involves:
- Cutting rafters or joists
- Creating a new opening
- Enlarging an existing opening
- Loft conversion
- Structural support
- Insulation
- Ventilation
- Safety glazing
- Fire escape
- Electrical wiring
- Waterproofing
- Changes to roof loading
The contractor or designer should confirm the requirements before work begins.
Roof Window vs Skylight Maintenance
| Maintenance Task | Roof Window | Skylight |
| Clean glass | Usually from inside or by rotating sash | May require external access |
| Check seals | Once a year | Once a year |
| Clear flashing | Remove moss and debris | Clear kerb and outlets |
| Lubricate hinges | Where manufacturer permits | Only on opening units |
| Check controls | Manual, electric or solar | Electric opening where fitted |
| Inspect after storms | Yes | Yes |
| Check condensation | During winter | During winter |
| Inspect roof covering | Tiles and flashing | Flat membrane and upstand |
| Service blinds | As required | Product dependent |
Which Usually Lasts Longer?
Lifespan depends on product quality, installation and maintenance.
A well-installed roof window may last 20 to 30 years or longer. Some parts, such as seals, glazing or mechanisms, may need attention sooner.
A fixed skylight may also last for decades, although its surrounding roof membrane may need replacement before the glazing.
Possible lifespan-limiting factors include:
- Seal failure
- Frame rot
- Misted glazing
- Flashing damage
- Roof membrane failure
- Corrosion
- Motor failure
- Poor drainage
- UV exposure
- Building movement
Can Roof Windows and Skylights Be Repaired?
Yes.
Common roof window repairs
- Seal replacement
- Flashing repair
- Glass replacement
- Handle repair
- Hinge replacement
- Motor replacement
- Timber frame repair
- Tile and underlay repair
Common skylight repairs
- Glazing seal replacement
- Kerb repair
- Membrane patching
- Glass replacement
- Dome replacement
- Motor repair
- Lantern joint resealing
- Drainage clearance
Repair usually makes sense where the main frame and roof structure remain sound.
When Is Replacement Better?
Consider full replacement where:
- The frame is rotten
- Glass has failed repeatedly
- Parts are obsolete
- Leaks continue
- The unit has poor insulation
- Several seals have failed
- The opening mechanism is badly worn
- The roof is being replaced
- A larger unit is wanted
- The original installation was incorrect
Replacing an old roof window during a re-roof can reduce repeat labour.
Roof Window vs Skylight Advantages
Roof window advantages
- Usually opens
- Good outside view
- Useful ventilation
- Suitable for loft rooms
- Standard sizes available
- Wide choice of blinds
- Often easier to clean
- Replacement parts commonly available
- Can sometimes support escape requirements
Roof window disadvantages
- May require rafter alteration
- Can cause overheating
- Moving parts need maintenance
- Flashing must match roof covering
- Usually designed mainly for pitched roofs
- May be difficult to reach if installed high
Skylight advantages
- Works on flat and pitched roofs
- Fixed versions can be simple
- Large custom sizes available
- Strong overhead daylight
- Useful for central areas of a home
- Can preserve privacy
- Wide choice of shapes
- Suitable for extensions
Skylight disadvantages
- Fixed units do not ventilate
- External glass may be difficult to clean
- Large rooflights can be expensive
- Flat-roof details must be carefully waterproofed
- Heat gain and glare can be significant
- Custom units may have long lead times
Roof Window vs Skylight Comparison Table
| Question | Roof Window | Skylight |
| Best for pitched roofs? | Yes | Yes, depending on product |
| Best for flat roofs? | Only specialist flat-roof models | Yes |
| Opens for ventilation? | Usually | Optional |
| Gives an outside view? | Usually | Sometimes |
| Suitable for loft conversion? | Usually best | Possible |
| Suitable for flat extension? | Less common | Usually best |
| Easy to clean? | Often | Product dependent |
| Standard sizes? | Common | Common and custom |
| Electric options? | Yes | Yes |
| Blinds available? | Widely | Product dependent |
| Fixed option available? | Some models | Very common |
| Fire escape potential? | Some models | Only opening units designed for it |
| Custom shapes? | Limited | Wide range |
| Typical installation cost | Moderate | Low to very high |
Which Should You Choose?
Choose a roof window when:
- The room is within a pitched roof
- You want ventilation
- An outside view matters
- The window will be within reach
- You need compatible blinds
- A standard replacement is required
- The room is a loft bedroom or office
- Easy cleaning is important
Choose a skylight when:
- The roof is flat
- The main aim is overhead daylight
- The unit can remain fixed
- The room is an extension, hallway or kitchen
- Privacy matters
- A large custom glass area is wanted
- The opening is too high for manual operation
- A roof lantern or architectural feature is planned
Can You Combine Roof Windows and Skylights?
Yes.
A property may use:
- Roof windows in loft bedrooms
- A flat skylight above an extension
- A sun tunnel in an internal bathroom
- A roof lantern over a kitchen
- Fixed glazing beside opening roof windows
Using different systems allows each room to receive the most suitable type of light and ventilation.
Questions to Ask Before Choosing
Ask the roofer, installer or designer:
- Is the roof pitched or flat?
- What is the roof angle?
- Do I need the unit to open?
- Will it be within reach?
- How much daylight is needed?
- Is an outside view important?
- What direction does the roof face?
- Could the room overheat?
- What glazing is recommended?
- Will rafters or joists need altering?
- Is planning permission needed?
- Will Building Regulations apply?
- What flashing or kerb system is included?
- How will the opening be insulated?
- Are blinds or shutters available?
- How will the outside glass be cleaned?
- What guarantee is included?
- What maintenance will be required?
What Should a Quote Include?
| Quote Item | Why It Matters |
| Product type and model | Confirms what is being installed |
| Fixed or opening | Affects ventilation and cost |
| Frame and glass size | Defines the glazed area |
| Glazing specification | Affects safety and energy performance |
| Flashing or kerb | Essential for waterproofing |
| Structural work | Covers altered rafters or joists |
| Roofing work | Includes tiles, felt, EPDM or GRP |
| Insulation | Reduces heat loss and condensation |
| Internal lining | Determines finished appearance |
| Plastering | May be priced separately |
| Electrical work | Needed for powered units |
| Scaffolding | Can form a major cost |
| Waste removal | Clarifies site clearance |
| Building control | Confirms responsibility |
| Guarantee | Explains aftercare |
Common Buying Mistakes
Choosing by Name Alone
The terms skylight and roof window overlap. Check the actual product features.
Buying a Fixed Unit When Ventilation Is Needed
A fixed skylight cannot release warm air.
Ignoring Cleaning Access
High fixed glazing may need specialist cleaning.
Choosing Too Much Glass
Large rooflights can cause overheating and glare.
Ordering the Wrong Flashing
Flashing must match the roof covering and window.
Ignoring Roof Pitch
Not every product suits every roof angle.
Forgetting Structural Costs
The glazing may cost less than the work needed to alter rafters or joists.
Assuming All Skylights Are Walk-On
Most are not designed to carry foot traffic.
Ignoring Internal Finishing
Plastering and decoration can add significantly to the cost.
Choosing a Cheap Unit for a Valuable Room
A garden store and a heated bedroom have very different performance needs.
Frequently Asked Questions
What is the difference between a roof window and a skylight?
A roof window is normally an opening glazed unit installed within a pitched roof. Skylight is a broader term that can include fixed and opening glazing on both pitched and flat roofs.
Is a VELUX window a roof window or a skylight?
A standard opening VELUX unit installed into a pitched roof is generally described as a roof window, although many homeowners also call it a skylight.
Which is better, a roof window or a skylight?
A roof window is usually better for a loft room needing ventilation and an outside view. A skylight is often better for bringing overhead daylight into a flat-roof extension.
Do skylights open?
Some skylights open manually, electrically or using solar power. Others are permanently fixed.
Do roof windows always open?
Most roof windows open, although fixed roof-window products are also available for certain installations and combinations.
Which option gives more daylight?
Either can provide strong daylight. The result depends on glass area, position, roof orientation, room shape and surrounding obstructions.
Which is cheaper to install?
A standard pitched-roof window may cost less than a large flat-roof skylight. However, small fixed skylights can sometimes be cheaper than opening roof windows.
Can a roof window be fitted to a flat roof?
Standard pitched-roof windows are not normally fitted directly into a flat roof. Specialist flat-roof window systems and raised bases are available.
Can a skylight be fitted to a pitched roof?
Yes. Fixed and opening skylights can be installed on pitched roofs, provided the product and flashing suit the roof angle and covering.
Which is easier to clean?
Many roof windows rotate for cleaning from inside. Fixed skylights may require external access unless they have self-cleaning glass or another maintenance solution.
Which is better for ventilation?
An opening roof window is usually a practical ventilation option. Opening skylights can provide similar benefits, particularly when they are electrically operated.
Which is best for a loft conversion?
An opening roof window is usually the most practical choice because it provides daylight, ventilation and an outside view.
Which is best for a kitchen extension?
A flat-roof skylight or roof lantern is often a good choice because it brings daylight into the centre of the extension.
Are roof windows more likely to leak?
No. A correctly installed roof window should remain watertight. Most leaks result from flashing, roof covering, seals or poor installation.
Do I need planning permission for a roof window or skylight?
Many installations fall within permitted development, but listed buildings, conservation areas, projection limits and larger alterations may require consent.
