Open up your home
with a stunning bi fold door

includes delivery


Supply and installation service from £880 per glazed door leaf, includes measuring fitting and 10 year guarantee contact us here.

Built around a belief that beauty doesn’t have to compromise performance, WarmCore aluminium folding sliding doors were created out of a desire to combine the desirability and durability of aluminium with unparallelled insulation. The orange thermal core – hidden away in the finished doors – is key to why WarmCore doors are 25% more thermally efficient than traditional aluminium systems. “Built with a revolutionary thermal core at its heart…”

Available Colours

supply only – or Fully Fitted


bi-fold doors


At the heart of WarmCore products is a thermal core which significantly out-performs the polyamide thermal breaks commonly used to reduce the threat of cold bridging on aluminium windows and doors. The result is an innovative “warm aluminium” frame construction, carefully dimensioned to provide an optimised 70mm front-to-back overall sash frame depth while ensuring market-leading thermal performance thanks to the multi-chambered insulating core.

Fully concealed multi-chambered cores substantially improve thermal performance when compared to thermally-broken aluminium doors:

U-value of 1.4 W/m2K with 28mm double glazing
U-value of 1.0 W/m2K with 44mm Triple glazing

U-Values Explained

A U-Value is basically a measure of heat loss through a structural element. It is calculated on the rate at which heat transfers through 1 square meter of a structure and is stated in W/m²K. U-Values are used by the construction industry to compare the thermal performance of different materials and products.

* Data correct at time of publication. Based on nine UK aluminium double glazed folding sliding doors and with the following U-Values: 1.94, 1.87, 1.85, 1.83, 1.83, 1.81, 1.77, 1.76

bi-fold doors


Precision-manufactured with a high quality surface finish and affording slim sightlines when installed, aluminium has become the material of choice for premium folding sliding door applications. WarmCore doors utilise a composite of materials to ensure an end product that is energy efficient and recyclable combined with the premium quality, structural integrity and architectural design elegance of aluminium to create a product perfect for both residential and commercial building applications.

bi-fold doors


An attention to detail that goes as far as creating bespoke union mouldings for gaskets ensures WarmCore outperforms the competition.

From the rollers to the handles to the corner assemblies, WarmCore displays an elegance of design that translates into a high performance installed product that looks outstanding.

Hardware available in Matt Black, Satin Silver and Brushed Graphite

bi-fold doors

Glazing Options

WarmCore doors can be glazed with 28mm double glazed units or 44mm triple glazed units. Glazing can be carried out with a choice of aluminium beads for a neat internal finish.

We recommend Celsius Glass, our exclusive range of high performance glass. Celsius Clear is specially formulated for vertical glazing and offers an impressive thermal performance to complement WarmCore.

bi-fold doors

Threshold Options

Sill options include a WarmCore standard threshold with integral sill, or standard threshold with an additional 150mm thermally-broken aluminium sill.

The Part M compliant low threshold design is thermally-broken aluminium and optional ramps and cover trims can be used internally, externally or both, depending on requirements.

Part M compliant low threshold can also be installed without any ramps, so that flooring can be laid up to the edges of the threshold or the threshold can be neatly set into the floor to create a flush floor level through the doorway.

bi-fold door

Integrated sill option

bi-fold door

Low threshold option

bi-fold door

150mm sill option

Measuring and surveying guide

Step 1
Measure the width of the aperture in at least 3 different places top middle and bottom. Take the smallest of these and deduct 10 mm to obtain the width of the door set.

Step 2
To determine the height of the door first find where the finished floor level
will be including any floor covering.
Now determine where the sill (or threshold) will sit. Measure the height
of the door from the underside of the threshold or sill. Take a minimum
of three measurements as indicated, use the smallest of these
dimensions and deduct 10mm to give the overall height of the door set
including sill (or threshold).

Step 3
Check the aperture is square by comparing the diagonal cross corner

Step 4
Please ensure that the following points are considered when surveying for
a new WarmCore folding sliding door:

  1. Floor levels in relation to the height of the track and frame.
  2. Evaluate the position of the plaster line and the need for minimal disturbance to interior decor.
  3. The head of the door will normally be fitted to a lintel, please ensure that the lintel manufacturer’s guidelines are adhered to.
  4. Make sure there is plenty of clearance for the doors to open in the direction that they will travel.

Bi Fold Door Downloads

warmcore brochure

Bi Fold Door Brochure
8.83 mb


Bi Fold Door Installation Guide
6.5 mb

Bi Fold Door Door Gallery

Click here to start designing, FOR AN INSTANT QUOTE. Start Designing