An ideal choice for low-energy projects, whether simply replacing your windows or specifying your new home.
Lacuna bi-fold door
Triple glazed timber bi-fold/ foldaside door that meets Part Q security requirements. Suitable for newbuild and retrofit projects.
U value
from 0.85 W/m2k
heat treated timber
for long term dimensional stability, revolutionising bifold doors.
Airtightness
Class 4 airtightness with multiple compression seals
Security
PAS 24 and Part Q compliant
Features of the lacuna bifold doors
Low 36mm threshold
The thermally broken threshold can be set below floor level on the inside to create a low accessible threshold.
Weather exposure
All of our products are third party tested to the highest levels of exposure.
Triple glazed as standard
with warm edge glazing spacers, argon filled cavities and low E coatings.
Technical data
Frame sections available in all formats, PDF and DWG. Backed up with PHPP ready data.
80kg max sash weight
This allows for sash widths up to 900mm to maximise glazed areas.
Profiles
Slim profiles between the sashes maximise the glazed areas.
Thermally modified timber
Lacuna uses thermally modified timber to reduce moisture content and increase the durability class, this results in an exceptionally dimensionally stable timber which will not change with the fluctuating temperatures.
Supplied all over the globe
Withstanding the harshest climates from Scandinavia to central Africa.
Simple installation
The frame is supplied flat pack and is easily built following simple step by step instructions, provided in both written and video format.
Discover our triple-glazed windows, available to make unique to you.
FAQs
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Approved Document Q of the Building Regulations for England became mandatory for all new dwellings on 1 October 2016. This means that windows and doors in new dwellings, where Part Q is applicable, will need to be security tested to PAS 24, or equivalent standard.
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Either a window or doorway, any part of which is within 2m vertically of an accessible level surface such as the ground or basement level, or an access balcony, or a window within 2m vertically of a flat or sloping roof (with a pitch of less than 30°) that is within 3.5m of ground level.
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21 Degrees windows & doors are all made from timber. Our ranges are made from FSC® certified Redwood or Oak. Modern timber finishes are now so durable that, for most applications, we recommend them over aluminium cladding or UPVC.
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U-Values measure how well heat is transferred by the entire window/ door – the frame, sash and glass – either into or out of the building. The lower the U-Value number, the better the window or door will keep heat inside a building on a cold day.
Download our Lacuna bi-fold doors technical information
Download our technical drawings and UKCA declarations regarding Lacuna bi-fold doors.
Download now
Lacuna bi-fold doors
Take a look at our Lacuna Bi-fold doors for low energy & Passivhaus projects. With low U values and aluminium-clad doors available too, these doors can really enhance the style and design of your project with standard and contemporary designs.
Low U values
Argon-filled triple glazing as standard for comfort and great thermal performance
Airtightness
Dual compression seals ensuring long-term class 4 airtightness
High security
Multipoint locking tested to Secure by Design standard
Be inspired
See our entrance doors for our clients within our case studies.
Certified and quality tested
All of our products are thoroughly tested and quality assured.
FSC Certified Wood
Part Q Compliant
Secured by design
How can we help?
Visit our showrooms
Windows are a big investment, so come and visit our showrooms or catch us at exhibitions around the UK to see our products for yourself.
Request a quote
Tell us about your project, and we'll make sure you get a no-obligation quote from us. Take a step towards a more energy-efficient home today.
Get in touch
We offer a friendly and responsive aftersales service for our windows and door ranges, with a dedicated office and on-the-road aftercare team.
