GDO Pro 20mm Vertical Medium Rib Chester with Window (32 Colour Options) garage door Steel GDO

GDO Pro 20mm Vertical Medium Rib Chester with Windows

Striking asymmetric design with glazing

The GDO Pro 20mm Vertical Medium Rib Chester with Window combines a smart, contemporary vertical ribbed design with a distinctive offset glazed section to create a door that looks different to a standard side hinged model. The 1/3 and 2/3 split is a key part of the Chester styling, with the window positioned in the wider leaf to provide a striking, modern appearance and a practical everyday access door. This makes the Chester with Window an ideal choice for garages that double up as workshops, hobby spaces, utility areas or secure storage, where light and easy pedestrian access are just as important as security.

20mm insulated construction

Behind the styling, the door uses the proven GDO Pro 20mm insulated construction. Each leaf is formed from twin steel skins bonded to a thermal core, creating a 20mm deep insulated panel that offers a big improvement in strength, stability and climate control compared with basic single skin pressed steel doors. Both leaves are factory mounted into a box section steel sub frame for simple on site installation, so the complete doorset arrives ready to fix with all hinges, hardware and threshold already in place.

Made to measure 1/3 : 2/3 layout

The Chester with Window is made to measure as standard at no extra cost, ensuring a neat fit to your existing garage opening. All doorsets in this design are supplied exclusively in a 1/3 : 2/3 split configuration to suit the window layout, but you can still choose whether the active wider leaf is on the left or right, and whether the doors open outwards as standard or inwards on request. Concealed shoot bolts secure the inactive leaf at the head and cill, while a robust lock on the main leaf can be upgraded to a three point locking system on suitable door sizes (minimum height over frame 1600mm) for enhanced security.

Window glazing choices

The integrated window section is designed to bring natural light into the garage, making it more comfortable and practical for regular use. You can specify the glazing in either clear or stippled finish, allowing you to prioritise maximum light transmission or greater privacy depending on how visible the garage is from the street. Both glazing options are tough and secure, and are designed to work in harmony with the insulated door construction to help maintain good thermal performance.

Finishes, hardware and overall benefits

Every Chester with Window doorset is manufactured in the UK and finished in a durable powder coat stipple texture for long term good looks and low maintenance. White is offered as the standard colour at no extra charge, with a wide range of other popular shades available in the standard options list and special RAL colours available on request. Optional stainless steel long bar handles in two different lengths can be specified as a pair for a more architectural look, while a standard lever handle is fitted as standard, with various finishes to coordinate with your chosen door colour.

Together, these features make the GDO Pro 20mm Vertical Medium Rib Chester with Window an excellent solution for busy, multi use garages or integral garages where appearance, insulation, security and day to day usability all matter.

GDO Pro 20 insulated side hinged doorset specification

The GDO Pro 20 is a made to measure, double skinned insulated steel side hinged garage doorset designed for everyday use where improved strength, security and thermal performance are important. Supplied pre assembled in its aluminium sub frame, it arrives as a complete doorset ready for straightforward installation on site.

Door construction and insulation

The door leaves are manufactured using 20mm double skinned insulated steel panels, helping to improve rigidity and reduce draughts and heat loss compared with basic single skin steel doors. The inner face is neat and flat for a clean internal appearance, making this an ideal choice for integral garages, workshops and garages used regularly.

Sizes and dedicated configuration

Each doorset is made to measure to suit your opening sizes, up to 2750mm wide and 2340mm high. To accommodate the distinctive Chester window styling, this specific model is exclusively manufactured with an asymmetric 1/3 and 2/3 split. You can choose whether the wider active leaf (which houses the window) is positioned on the left or the right side of the opening.

Window and glazing options

The signature feature of the Chester design is the integrated top window section in the wider active leaf, designed to bring valuable natural daylight into your garage. To perfectly suit your privacy needs, the window can be specified with either clear or stippled glazing. Both options are tough, secure, and designed to work with the insulated panel to maintain excellent thermal performance.

Aluminium sub frame supplied and factory fitted

The GDO Pro 20 doorset is supplied pre hung and factory fitted within its aluminium sub frame as standard, helping ensure accurate alignment and a faster, simpler installation. The frame and threshold arrangement also supports effective sealing around the perimeter for improved weather protection.

Security and locking

The doorset is designed to provide improved security for everyday garage use, with a robust lock and secure inactive leaf retention via concealed shoot bolts. For an added level of security, a 3 point locking upgrade is available on suitable door sizes (minimum height over frame 1600mm).

Hinges and alignment adjustment

Colour matched hinges are supplied and are adjustable in three directions to help fine tune alignment of the door leaves on installation.

Weather sealing

Double seals to the door leaf and frame help protect against the weather and limit dust and debris entering your garage.

Handle and finish options

The standard specification includes a lever handle available in various finishes (such as Bronze effect, Gold effect, or Satin) to complement your chosen door colour. Alternatively, you can opt to upgrade to striking stainless steel long bar handles (supplied as a pair in two different lengths) for a more architectural, modern exterior look.

Colours

Choose from 32 colour options in a durable stipple effect powder coated finish, designed for long term appearance and low maintenance. White is offered as standard, with a wide range of premium colours and special RAL options available.

Matching pedestrian side door

If you also need a separate access door, a matching GDO Pro 20 Vertical Medium Rib personnel door is available with the same insulated construction and styling, so you can keep a consistent look across the property: View the matching Pro 20 personnel door.

3 Point Locking
For the GDO Pro 20mm Vertical Medium Rib Chester with Window, you can enhance security further with an optional 3 point locking upgrade. This system uses twin hood locks to secure the active leaf at multiple points, helping to resist forcing and prying attacks.
Minimum height over frame for 3 point locking is 1600mm.

Hinges
Heavy duty hinges are supplied colour matched to your chosen door finish and are fully adjustable in three directions. This allows the installer to fine tune the alignment of the asymmetric 1/3 and 2/3 leaves, ensuring a precise fit and smooth operation even on openings that are slightly out of true.

Seals
Double seals are fitted to both the door leaves and the surrounding frame, helping to protect the interior of your garage from wind, rain and drafts. These seals also help to limit dust and debris entering the space, which is especially beneficial where the garage is used regularly as a workshop, utility area or hobby room.

Window Glazing Options
The distinctive glazed section in the wider Chester leaf is designed to let natural light into your garage while maintaining a smart exterior appearance. You can choose between clear glazing, which maximises light levels inside, or stippled glazing, which softens the view and provides greater privacy from the outside. Both glazing types are tough and secure, and work in harmony with the insulated steel construction to support good thermal performance.

Handle Options
You can tailor the look and feel of your Chester doorset with a choice of handle finishes. Standard lever handles are available in Bronze effect (dark brown appearance), Gold effect or Satin effect so you can coordinate with other hardware on your property. Alternatively, you can upgrade to stainless steel long bar handles for a more contemporary, architectural appearance on the 1/3 and 2/3 split leaves.

Door Stays
Friction door stays are fitted as standard at no extra charge. These help to hold the doors in the open position and prevent them from blowing shut in windy conditions, improving day to day usability and safety.

Colour Options
The Chester with Window is available in a choice of 32 colours in a highly durable powder coat ripple texture finish, designed for long term appearance and low maintenance.
Choose from the classic low gloss solid colours as below:

STANDARD FOC COLOURS:
White RAL9016
Black RAL9005
Grey RAL7016

PREMIUM COLOURS
Signal Grey RAL7004
Dusty Grey RAL7037
Traffic Grey RAL7042
Light Grey RAL7035
Window Grey RAL7040
Basalt Grey RAL7012
Pebble Grey RAL7032
Iron Grey RAL7011
Slate Grey RAL7015
Graphite Grey RAL7024
Agate Grey RAL7038
Black Grey RAL7021
Steel Blue RAL5011
Cobalt Blue RAL5013
Sky Blue RAL5015
Gentian Blue RAL5010
Signal Blue RAL5005
Light Blue RAL5012
Moss Green RAL6005
Fir Green RAL6009
Chartwell Green BS14 C 35
Ruby Red RAL3003
Traffic Red RAL3020
Chocolate Brown RAL8017
Clay Brown RAL8003
Mahogany Brown RAL8016
Light Ivory RAL1015
Cream RAL9001
Traffic Yellow RAL1023

Installation Guidance for GDO Pro 20 Doorsets

One of the biggest advantages of the GDO Pro 20 insulated side hinged garage door is that it is delivered fully pre-assembled. The insulated door leaves come factory hung within their heavy duty aluminium sub frame, eliminating the need for complex assembly on site. This "all in one" approach significantly reduces installation time and ensures factory accurate tolerances from the start.

While full, detailed manufacturer fitting instructions are provided with the door, the standard installation process follows these key steps:

1. Preparation and Checking

Before removing your old garage door, carefully measure your new GDO Pro 20 doorset and check it against your structural opening to ensure it will fit. Make sure the floor where the threshold will sit is solid and completely level; an uneven floor can cause the doors to catch or prevent the weather seals from working effectively.

2. Positioning the Doorset

Because the doors and frame are pre-assembled, they should be offered into the structural opening as one complete unit. Keep the door leaves closed and locked during this stage to keep the frame rigid. Use plastic packers or timber wedges between the aluminium frame and the brickwork to hold the doorset securely in place. Use a high quality spirit level to ensure the frame is perfectly plumb, square, and level.

3. Fixing the Frame

Once you are completely satisfied that the frame is perfectly upright and square, drill through the aluminium fixing sub frame and into the structural opening. Secure the frame using appropriate masonry frame fixings (not supplied). It is important not to over tighten the fixings, as this can bow the aluminium frame and pinch the door leaves.

4. Securing the Threshold

The doorset features a built in threshold that must be firmly fixed to the floor. Ensure a line of sealant is applied beneath the threshold before final fixing to prevent water from tracking underneath into the garage.

5. Testing and Final Adjustments

Once the frame is fully secured, unlock and open the door leaves to check their operation. They should swing smoothly without catching. If slight adjustments are needed due to the opening being slightly out of square, the GDO Pro 20 features heavy duty 3-way adjustable hinges. These allow you to finely tune the position of the door leaves in three directions for a perfect, even gap and smooth lock engagement.

6. Perimeter Sealing

Finally, once the door is operating perfectly, apply a high quality exterior silicone sealant around the entire perimeter gap between the aluminium frame and the brickwork to ensure the installation is completely weather tight.

Please note: We always recommend downloading and reading the full official installation manual prior to beginning work.

Installation instructions can be found here

GDO Pro 20 Warranty & Guarantee

The GDO Pro 20 side hinged garage door is manufactured in the UK to exacting engineering standards. To provide you with complete peace of mind, your doorset is backed by a comprehensive manufacturer's warranty. To ensure the validity of these guarantees, the door must be installed, operated, and maintained in accordance with the supplied manufacturer instructions.

10 Year Safe and Reliable Operation

The main structure of the GDO Pro 20 door is covered by a 10 year warranty ensuring safe and reliable operation. This provides long-term confidence in the core structural integrity and safety of your garage doorset.

2 Year Hardware and Component Guarantee

A 2 year warranty is provided on all moving and mechanical parts under normal daily use (defined by the manufacturer as up to 5 open/close operations per day). This comprehensive cover includes all primary hardware such as hinges, locking mechanisms, shoot bolts, and handles.

2-Year Factory Paint Finish

The factory-applied powder coat colour finishes are covered by a 2 year warranty against primary paint failure. Please note: As is standard with steel door manufacturing, the rolling and pressing process may cause slight natural distortion which can become apparent under certain lighting, and minor cosmetic blemishes are considered normal. The internal rear face of the door is not designed to have the exact same uniform cosmetic finish as the exterior.

Coastal and Estuary Exclusions

Please be aware that any steel doors fitted within 250 metres of the coastline (where the beach ends and the land begins) or directly adjacent to an inland estuary are strictly exempt from the paint finish warranty due to the highly corrosive saline environment.

Key Warranty Conditions and Exclusions

• Inspection upon Delivery: Goods must be carefully inspected upon arrival. Any transport damage or missing items must be reported within 48 hours of receipt. By proceeding to install the garage door, you acknowledge and accept its visual condition; no claims for cosmetic damage can be accepted once the item has been installed.
• General Maintenance: The door panel must be kept clean and free from impact damage. Any accidental areas of paint damage must be dressed with touch-up paint as soon as possible to prevent corrosion. Regular cleaning and light lubrication of the moving parts is required.
• Warranty Invalidation: Improper installation, structural modifications, repairs by non-qualified individuals, or damage caused by severe external influences (such as fire, flooding, alkaline solutions, bird droppings, or abnormal atmospheric pollution) will completely invalidate the warranty.

Always remember to allow for some fitting tolerance when ordering. In a perfect world we would recommend about 10mm all round, meaning you measure the width and height and then take 10mm off the smallest dimensions all round and this gives the Ordering Sizes. In real world apertures the floor is often not level and the aperture not totally square so please make sure you allow enough tolerance to cater for any out of square dimensions.