Windows & patio doors

Let the light in.

Windows and patio doors composed for the way you live: warmer, quieter, and open wider than the house you grew up in.

Compose yours See the patio doors

Every room has a view.
Give it a frame.

0.66W/m²K, whole-window Uw¹

47 dBsound reduction with acoustic glass¹⁰

400 kgper sliding leaf, moved with one hand⁶

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Seven chambersstill air is the insulator
Steel coregalvanised reinforcement in frame and sash
Three sealsouter, centre and inner sealing planes
Three panes, two argon cavities4 / 18 / 4 / 18 / 4 mm, low-e coatings, Ug 0.5
Warm-edge spacerno cold bridge at the glass edge

Anatomy

Seven chambers of quiet.

Cut a window in half and you find the reason it is warm: still air trapped seven times over, a steel spine, three seals and two cavities of argon between three panes.¹

0chambers

82mmprofile depth

1.40Uw, W/m²K

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Closedthree seals, locked all round
Tilta quiet trickle of air, secure at night
Turnwide open, cleaned from inside

Tilt & turn

Tilt. Turn. Breathe.

One handle, two ways to open. Turn it up and the sash tips in at the top for background air; turn it level and it swings wide. Hidden hinges carry up to 150 kg and vanish when it closes.¹

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Light studio

Daylight, by the hour.

Drag the sun across a south-facing room and watch the light walk across the floor. A glass wall of ten square metres is the cheapest lamp you will ever own.¹³

Time of day 09:00

0m²sunlit floor

10.3m²glass

63%of the wall

Low morning sun reaches deep into the room

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Glazing lab

Three panes, one climate.

A thermal camera on a winter night. Cold glass pulls the warmth off your skin and drips condensation; triple glazing keeps the inside pane within a couple of degrees of the room.¹²

Outside -5 °C

17°Cinside glass surface

0.5Ug, W/m²K

Dry glassat 20 °C, 50 % RH

Street outside 72 dB

38dBinside, like a library

Rw 36sound reduction¹⁰

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Materials

Three ways to build a frame.

Warmest value

PVC

Corner of a white PVC window frame with a silver handle

Depth: 82 mm
Uw from: 0.66 W/m²K¹²
Sound: up to 47 dB
Security: RC2
Leaf up to: 1.6 × 2.4 m
Finish: Woodgrain and smooth foils, 20+ decors; colour-core and aluminium-clad options
Care: Wipe clean; no repainting

Seven-chamber profiles with three sealing planes and steel-reinforced sashes: the warmest cost-to-comfort ratio for most homes.

PVC windows

Slimmest sightlines

Aluminium

Depth: 77 mm
Uw from: 0.76 W/m²K³⁴
Sound: up to 47 dB
Security: RC2 on request
Leaf up to: 1.8 × 2.8 m
Finish: Any RAL powder coat, anodised, wood-effect and textured; different colour inside and out
Care: Powder coat, no maintenance

Three-chamber profiles with polyamide thermal breaks: the narrowest frames, the largest leaves, and any colour on each face.

Aluminium windows

Natural warmth

Wood & wood-aluminium

Corner of an oak window frame with an aluminium cladding edge

Depth: 88 mm
Uw from: 0.79 W/m²K⁵
Sound: up to 45 dB
Security: RC2 on request
Leaf up to: 1.5 × 2.4 m
Finish: Laminated pine, meranti, oak or larch; stains and opaque lacquers; optional aluminium cladding outside
Care: Re-coat every few years, or clad in aluminium

Laminated pine or meranti in 68, 78 or 88 mm depths. Outside, an aluminium shell can take the weather for it.

PVC windows

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A sunny garden with a lawn, an apple tree and a bench, as seen from inside

Colour lab

Colour, inside and out.

AnthraciteRAL 7016

Inside: White. Woodgrain to the street, white to the room: every frame can wear two colours, and the same finish carries to your front door, garage door and gate.³

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Patio doors

Where the room ends,
the garden begins.

Lift. Slide. Six metres of summer.

Turn the lever and the leaf rises a few millimetres off its seals onto rollers. Four hundred kilograms of glass glide with one hand.⁶

0.0 mopening width

400 kgper leaf

Nothing underfoot.

The running rail sinks into the floor, so the room simply continues onto the terrace and dinner moves with the sun. Fixed panes glazed straight into the frame let in up to 10 % more light.⁷

Compose a lift & slide door Aluminium lift & slide doors

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The family house from the lawn, its lift-and-slide door open: one leaf parked in front of the fixed pane and the living room open to the terrace

The same opening with a tilt-and-slide door: the leaf has stepped into the room and slid across in front of the fixed pane

The same opening with bi-fold doors folded back to one side, the whole wall open onto the terrace

The same opening with a pair of French doors swung out onto the terrace between fixed side lights

Plan view

Four ways to open a wall

Lift & slide

The widest wall you can open.

Leaf up to
Leaf weight
Threshold
Uw

Best for: ⁶⁷⁸⁹

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Threshold

Zero. The step you won’t notice.

A standard sill stands up to 48 mm proud of the floor.⁶ Sink the running rail into the floor build-up, put a drainage channel in front of it, and bare feet, prams and wheelchairs cross without a thought.

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A father checks the locked handle of a bedroom window at night while his child sleeps

Security

Locked all the way round.

Turn the handle and 0 cams hook behind their strikers. The glass stays in the frame when struck, and the handle locks with a key, so the nursery window is as safe as the front door.¹⁰¹¹

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The kitchen window with its roller shutter raised, sunlight on the worktop

A house with an external venetian blind lowered over a wide window; a woman reads inside and a man waters the garden

A family at dinner on a summer evening with the patio door open behind an insect screen

Shade & comfort

Shade on demand.

Roller shutterFoam-filled aluminium slats roll into a box above the window, in 18 colours and curtains up to 3.3 m wide. Dark bedrooms, winter insulation, summer shade and a curtain that detects obstacles.Roller shutters
External venetian blindSlats tilt through 90 or 180 degrees to let in light but not heat, in 20 colours. The best way to keep a south-facing glass wall cool without closing the view.
Insect screenPleated, roller or framed screens so the patio door stays open all summer evening.
Smart driveOne remote, an app or your home hub: shutters follow sunset, blinds follow the sun and the weather, the patio door opens by itself.

Shading ranges per the supplier data¹⁵

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Studio

Compose your opening.

Choose the opening, size it, colour it inside and out, pick the glass. The studio checks every decision against the system limits, estimates the Uw and the leaf weight, and writes your brief.¹⁴

The house from the garden with every window and the patio door in anthracite textured

Your home

One colour,
the whole house.

Windows and patio door in Anthracite. Pick a finish once in the colour lab and it follows you across the house: the same colour carries to the front door, the garage door, the fence and the gate.

Home Inclusive Garage doors Fences

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Questions

Questions, answered.

Which material should I choose: PVC, aluminium or wood?

PVC gives the warmest value and the widest decor range. Aluminium gives the slimmest frames and the largest leaves, and will take any colour. Wood is the natural choice for period homes and can be clad in aluminium outside so it never needs painting. The configurator below checks each material against the size you want.

What does Uw mean, and what number should I look for?

Uw is the heat loss of the whole window in watts per square metre per kelvin: lower is warmer. Around 1.2 is a typical replacement window, 0.8 is a very good one, and 0.6 or lower approaches passive-house level. The frame (Uf), the glass (Ug) and the spacer at the glass edge (psi) all count, so a large pane of good glass in a slim frame often beats a small one.

Double or triple glazing?

Triple glazing halves the heat loss through the glass and brings the inside surface close to room temperature, which stops the cold draught you feel near a window and removes condensation. It weighs about half as much again, so the hardware is specified for it. Double glazing still makes sense for unheated rooms, outbuildings and some listed facades.

How wide can a lift-and-slide door go?

A single leaf can weigh up to 400 kg and, in panoramic slim-frame systems, reach four metres wide, so a two-leaf door opens a wall of six metres or more and three- or four-leaf schemes go further. Motorised leaves go to 700 kg. The leaf rides on rollers, so it moves with one hand regardless of weight.

Can the threshold really be flush with the floor?

Yes. Flush thresholds sink the running rail into the floor build-up with a drainage channel in front of it, so the finished floor runs straight out onto the terrace. Where a drain is not possible, a low threshold of 20 to 48 mm, depending on the system, is the next best thing.

How secure are the windows?

RC2 resistance class is the recommended standard for homes: mushroom-head cams lock into anti-theft strikers around the perimeter, the handle locks with a key, hinge-side pins stop the sash being lifted, and laminated inner glass keeps the pane in the frame. RC3 and glass-break sensors are available where insurers or your own peace of mind ask for them.

Can the inside and outside be different colours?

Yes. Woodgrain or anthracite outside with white inside is the most common choice. Aluminium frames can be powder-coated in different RAL colours on each face; PVC uses foils, aluminium cladding or a colour-core profile.

What about noise from the road?

Standard triple glazing reduces sound by roughly 36 dB; acoustic laminated glazing reaches 47 dB, which turns a main road into a murmur. Good seals matter as much as the glass, which is why the frame has three sealing planes.

How long does it take, and what happens to the old windows?

Standard sizes leave the factory in as little as a week; a whole house is usually measured, made and fitted within a few weeks. Fitting a window takes a few hours per opening; the old units are removed and recycled, and the reveals are made good inside and out.

Is there a guarantee?

PVC windows and balcony doors carry a seven-year guarantee; patio doors and aluminium joinery five years; the sealed glazing units up to ten years. The quotation lists the exact cover for your configuration.

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Let the light in.

Measured, made and fitted by Watford Construction. Start in the studio, or talk to us about the house you have.

Request a quotation Back to the studio Contact

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Continue

Products, and the rest of the house.

A white PVC tilt-and-turn window with one sash tilted

WindowsPVC windowsSeven-chamber PVC windows in woodgrain, smooth and textured finishes.

An anthracite aluminium window with one sash open

WindowsAluminium windowsThermally broken aluminium windows in any RAL colour, inside and out.

An anthracite aluminium lift-and-slide door with one leaf open

Patio doorsAluminium lift & slide doorsPanoramic lift-and-slide doors with flush thresholds and leaves up to 400 kg.

White PVC French doors with a side light

Patio doorsPVC terrace doorsSliding, tilt-and-slide and French patio doors in warm PVC profiles.

A window with an anthracite roller shutter lowered two-thirds

ShadingRoller shuttersMotorised aluminium roller shutters for every window and door.

A house whose front door, garage door, windows and gate share one anthracite finish

ExperienceHome InclusiveOne colour across door, garage, fence and gate.

An anthracite sectional garage door half open at dusk

ExperienceGarage doorsOpen to more.

A horizontal-slat aluminium fence and sliding gate in front of a modern house

ExperienceFencesDraw the line.

Notes and references

PVC window profiles: seven-chamber systems 82 mm deep with three sealing planes, class A profile walls to EN 12608, steel-reinforced sashes and triple glazing 4/18/4/18/4 (Ug 0.5) as standard; whole-window Uw from 0.66 to 0.76 W/m²K at the 1,230 × 1,480 mm reference size, Rw 36 to 47 dB, RC2 certified variants. Values depend on size and glazing and are confirmed on the quotation.
Guarantee: seven years on PVC windows and balcony doors, five years on patio doors and aluminium joinery, up to ten years on the tightness of the sealed glazing units, two years on accessories, per the supplier terms current in October 2026.
Aluminium window profiles: thermally broken three-chamber sections with a 75 to 77 mm frame, glazing up to 65 to 70 mm, three EPDM seals; Uw from 0.76 to 0.77 W/m²K at the reference size; any RAL colour, textured and wood-effect finishes, different colours inside and out.
Passive-house capability: the window range includes systems certified by the Passive House Institute US (PHIUS, 2023); certification applies to specific configurations.
Timber windows in 68, 78 and 88 mm depths from laminated pine or meranti: Uw 1.08, 0.90 and 0.80 W/m²K; the wood-aluminium versions 0.90, 0.84 and 0.79.
Aluminium lift-and-slide doors: 77 mm leaves in a 174 mm two-track frame, leaves up to 400 kg, glazing 9 to 61 mm, 48 mm threshold in the standard build; the single-track version reaches Uw 0.75 W/m²K. Panoramic slim-frame sliders take sashes up to 4 m wide with a 25 mm interlock and 94 % glass, Rw 43 dB, 400 kg by hand or 700 kg motorised, with the rail flush in the floor. Maximum leaf sizes quoted on this page are typical system limits and are confirmed per order.
PVC lift-and-slide doors: seven-chamber 194 mm frames, leaves up to 400 kg on three-bolt lift-slide gear, a low threshold that can be hidden in the floor; Uw 0.71 W/m²K at 2.7 × 2.3 m and 0.65 for the slimmest version. Fixed panes glazed straight into the frame give up to 10 % more light than a conventional fixed leaf.
Tilt-and-slide doors: Uw from 0.65 W/m²K in seven-chamber PVC, sashes up to 160 kg on the tilt-slide gear; parallel-slide versions use nine-chamber profiles.
Folding doors: 86 mm aluminium leaves with triple glazing, Uw 1.1 W/m²K for a three-leaf set of 3.0 × 2.5 m, glazing 13 to 61 mm, three to seven leaves per set; leaf weights per set are confirmed on the quotation.
Glazing: Ug 1.0 W/m²K for double low-e argon units (4/16/4), Ug 0.5 for triple (4/18/4/18/4), Ug 0.4 for the warmest triple unit; acoustic laminates to Rw 47 dB; laminated anti-burglary glass (44.4) to class P4A; solar-control glass with g around 0.3; warm-edge spacers as standard on the newest systems. Typical catalogue values; the glazing lab calculates from them.
Burglar resistance to EN 1627: RC2 is the recommended class for homes; mushroom-head cams, anti-theft strikers, lockable handles and laminated inner panes are the usual package. RC3 on request. The locking points shown are illustrative; their number depends on the size of the sash.
Inside-surface temperatures and condensation in the glazing lab are calculated from Ug and a standard inside surface resistance of 0.13 m²K/W at 20 °C and 50 % relative humidity; the figures illustrate the physics and are not a thermal survey.
Daylight figures in the light studio are geometric illustrations for a 6 × 6.3 m south-facing room with a 4.8 m glass wall; real daylight depends on orientation, overhangs, neighbours and the sky.
Dimensions, weights, ratings and the estimated Uw in the studio are presentation ranges typical of the systems above and are checked by Watford Construction before any order; the composed brief is a starting point for a quotation, not a specification.
Shading: roller shutters with curtains up to 9 m² and 3,300 mm wide in 18 colours, obstacle detection and app control; external venetian blinds with 0 to 90 or 0 to 180 degree slats in 20 colours with weather automation; pleated and framed insect screens; smart-home control through the app, remote or hub.

The films, house views and photographs on this page are presentation visuals created for Watford Construction: the house, rooms, people and products shown are illustrative computer renderings and scenes, not a survey of a real home; the window and door drawings are not engineering drawings, and the thermal and daylight views are calculated illustrations. Colours, sizes and finishes are confirmed on the quotation.

The garden seen through the glass in the films is the panorama “Symmetrical Garden 02” by Dimitrios Savva and Jarod Guest (Poly Haven, CC0); the lawn and timber cladding use ambientCG textures (CC0).