We have options available when it comes to the door threshold. As standard we supply our thermally broken part M compliant threshold which needs to be sunk below the floor finishes to create a flush threshold. We have the option to remove the levelling profile which can then create a stepped threshold. We also have 3 extension sections which can be used to link the threshold to a drain or exterior surface.
U value
from 0.73 W/m2K
Flush threshold
Offering seamless integration between your interior and exterior spaces
Airtightness
Class 4 airtightness with dual compression seals
Security
SBD high security option (PAS 24 and Part Q compliant)
Triple glazed lift & slide doors
Our lift and slide doors are an excellent solution for large openings. Typically designed to have 2 sections with one sliding and one fixed. Our sliding section is to the inside which has multiple benefits. It means the door can slide fully behind the fixed unit as the handle is not in the way, this creates a great aesthetic when fully opened. This also means that the track in which the door slides is on the inside, so is not exposed to the weather and possible build up of dirt and debris which can affect the seals and functionality of a sliding door.
Despite the hefty weight of a sliding door it can be easily slid with very little force due to the lift and slide system, please see one of our videos or try it for yourself in one of our showrooms.
Lift & slide doors
Learn more about our triple glazed lift & slide door suitable for low energy and Passivhaus projects.
Features of our lift & slide door
Part M compliant
Our sliding doors come with a thermally broken part M compliant threshold as standard. Meeting the requirements for wheelchair access. We have the option to add extension sections or can remove the levelling profile if you require a stepped threshold.
Weather exposure
All of our products are third party tested to the highest levels of exposure.
Triple glazed as standard
All of our products use triple glazed units with swiss spacer ultimate warm edge glazing spacers, argon filled cavities and lowE coatings.
Consistent design across all sizes
Our windows are available in all traditional shapes and sizes, ensuring uniformity throughout your project.
Matching window ranges
All of our doors and windows are available in matching suites.
Technical data
Frame sections available in all formats, PDF, DWG and Revit. Backed up with PHPP ready data
Secured by Design (SBD)
When it comes to security we go above and beyond. All ranges are tested to the SBD standard which uses live police data to combat against the latest break in trends.
Soft close function
On request we can provide a soft close function to the sliding door.
Slim central mullion maximising light
GBS78-A and GBS98-A AluClad Timber have a slim 66mm central mullion. GBS78 and GBS98 timber doors have a slim 80mm central mullion. Ensuring the best aesthetic whilst maintaining structural stability, weather tightness and high security hardware.
Door thresholds
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. 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 lift & slide doors technical information
Download our technical drawings and UKCA declarations regarding our lift & slide doors.
Download now
Lift & slide doors
Take a look at our lift & slide 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.
Be inspired
See our lift& slide 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
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.
