Flush casement
The sash closes level with the frame in one flat plane; with no weather lip, each frame must sit true.
Aluminium casement windows
Outward-opening aluminium casement windows with a 32 mm thermal break, supplied and fitted across London from our Ruislip showroom.
01Aluminium windows
What is an aluminium casement window?
An aluminium casement window has a sash hinged at the side or top that opens outward, the traditional British way. Ours is a slim Cortizo profile, flush or with a classic weather lip.
Projecting casement
The sash sits proud of the frame with a weather lip over the seal, which suits older, out-of-square openings.
Side hung and top hung
Both open outward, side hung up to 42 kg and top hung up to 100 kg, with concealed hinges available.
Colour and texture
RAL powder coat, mottled or rough textures, wood effect or anodising, with an optional second colour inside.
02Our work
Fitted by our own team.
03Technical specification
Specification.
Every option is confirmed at survey, against your opening and your build stage.
- System
- Cortizo casement, aluminium with a 32 mm polyamide thermal break
- Frame and sash section
- 70 mm each
- Glazing
- Units from 23 mm to 44 mm
- Thermal performance
- Uw from 1.4 W/m²K double glazed, from 1.0 W/m²K triple glazed
- Acoustic insulation
- Rw up to 45 dB
- Weather tests
- Air permeability Class 4, watertightness Class E1200, wind resistance Class CE2400
- Maximum sash size and weight
- Slim: 950 x 1,300 mm side hung (35 kg), 1,200 x 1,300 mm top hung (50 kg). Heavy duty: 750 x 1,750 mm side hung (42 kg), 1,800 x 1,800 mm top hung (100 kg)
- Security
- PAS24 tested options available
- Finishes
- RAL, mottled and rough powder coats, wood effect, anodised, dual colour
- Lead time
- Made to order; confirmed with your quote
04Asked before every survey
The questions that matter.
Flush or projecting aluminium casement, which should I choose?
Flush suits modern elevations, projecting most older houses. Flush has no weather lip, so the frame must sit true or driving rain finds the gap. Projecting keeps the lip and forgives an out-of-square opening. Our own team fits both and advises per opening at survey.
How large can an outward-opening casement sash be?
Up to 1,800 x 1,800 mm top hung, or 750 x 1,750 mm side hung, on heavy-duty hardware. Weight sets the limit, between 35 and 100 kg by type. For a taller, heavier pane, or one cleaned from inside, choose tilt and turn.
Will an aluminium frame feel cold in winter?
Not with a thermal break. A 32 mm polyamide strip splits the profile, so the inner face stays near room temperature. Uw is from 1.4 W/m²K double glazed, 1.0 triple. A warm-edge spacer in the glass matters as much as the frame.
Why does mould appear around some new windows?
Usually the installation, not the window. A warm frame set into a cold brick reveal on foam alone makes a cold bridge, and condensation settles on the plaster beside it. The fix is insulated reveals and expanding tape round the perimeter, agreed at survey.
Is a slim aluminium casement secure?
Yes, with the right hardware. The casement system has passed a security test at the manufacturer's test centre. PAS24 tested options available, and we confirm the hardware specification with your quote.
05Start here
Start with a conversation.
- A render of the finished result before you commit
- Showroom in Ruislip, opposite Ruislip Manor station, with parking
- One team from survey through to installation
Prefer to talk?+44 20 3375 8609Not ready for prices? Send us a message instead