01535 603909

Our internal room dividers and screens have been designed to replicate the industrial appearance of old steel framework from a bygone era.

They are a fantastic solution for separating living spaces with a run through floor finish and allow high levels of natural light to flood between rooms.

Made to measure and available with flexible design options our glass room dividers and screens provide an elegant and minimalistic alternative to a building a solid wall.


Internal Aluminium steel look Partition Doors and Glazing partition wall

Key Features

  • Aluminium that looks like steel
  • Exclusive to Marlin Windows
  • Ultra slim framework
  • No threshold - floor finishes can run through
  • Elegant single and double door option
  • Thermally broken profiles throughout
  • Uses sealed units for thermal and acoustic control
  • Huge range of colours and special finishes
  • Authentic handle options
  • Secure multipoint locking



Rated 5.0 out of 5 Noel Brown

We are delighted with the finished product. All our other professional contractors on site have also commented how impressed they are with the Marlin product quality & finish. We have no hesitation in recommending Marlin & can only thank them again for their superb service.


Rated 5.0 out of 5 Andrew Beevers

...trumps the 'Crittall' type systems on thermal performance and cost.
The grasp of the importance of design and quality of manufacture from the Marlin Team is second to none.


Read the rest of these and our other 5 star reviews left on Google


Product Information

The Smart Alitherm Heritage door is the ideal replacement for steel doors on heritage applications such as building renovations or apartment conversions.

The Alitherm Heritage door provides the solution for conservation areas where planning regulations require a like-for-like product replacement.

Alitherm Heritage door profiles feature the system's signature slim sightlines and elegant lines that complement Smart's existing Alitherm Heritage window and mimic those of steel doors.

The system has all the advantages of modern aluminium profiles that feature polyamide thermal breaks, allowing the system to achieve a U Value of 1.6 W/m2k when installed with a suitable sealed unit.

Alitherm steel replacement door profile


Design Applications

External single or double open out heritage doors
Balcony Doors
Internal partition wall doors


Window Energy Rating ‘A’ – when using correct profile, glass unit & spacer bar
Thermal performance
1.6 W/m²K with 1.2 centre pane U value
1.4 W/m²K with 0.8 centre pane U value
Method of fabrication: corner crimping
24mm double glazed unit
Tape or gasket glazed
Multipoint locking
Traditional Art Deco handles available

Glazing and frame colour choice


Our aluminium profiles are polyester powder coated by our systems suppliers using the very latest paint application techniques guaranteed for 25 years.

SGG Planitherm sealed glass units complete our leading combination of products and finishes.

Read More

Document Downloads

File Type Document Description Download Document
Adobe PDF Alitherm Heritage
Section identification Guide
Download (33.5 MB)
Adobe PDF Alitherm Series
Supply only – Guide to installation
Download (403kb)

Technical Specification


Product Type Doors
Material Aluminium Polyamide
Dual Colour
Thermally broken


Max width 900
max height 2100
Max weight 60
Thermal suitability ★★★★★
Min Glazing 24
Max glazing 32

Locking options


Building suitability

light duty

The Buyers Guide To French Doors

guide to how to aluminium french doors

Read our guide to buying french doors for your home

Replacing Windows In A Listed Building

Read our guide to replacing windows in listed buildings

Read our guide to listed building window replacement

Replacing Windows In Conservation Area Properties

Read our guide to replacing windows in conservation area buildings

Read our guide to conservation area property window replacement


Why Choose Marlin Windows?

We care...

about the quality of finish
about you, your project and your property
about your 100% satisfaction

And we are rated ★★★★★ on Google

need more reasons? click here

Get A Quote

"our builder said they were the best supplier and fitter they had ever used"
Mrs Nellist Haworth, Yorkshire


Call 01535 603909