Leading specialist experience

Our management focus means your business is uniquely positioned to offer the best design service and products which are built to last and that will enhance your reputation.

We are the best at what we do, having provided secondary glazing solutions to our commercial partners across the UK for over 35 years.

Get a free quote

 A member of our commercial team will be in touch to discuss your initial enquiry.


 You'll be put in touch with a member of our regional commercial sales team who will arrange a visit if required.


 You'll be given access to further product information, drawings, specifications and pricing.


 You'll be able to complete your project with an industry-leading secondary glazing solution.

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Partner in commercial design

With a wide range of secondary glazing options from traditional to contemporary, as well as top-quality design support including technical drawings, let Granada provide the extra dimension to your original vision. We aim to be part of the design or renovation of a property from the initial design process to final installation.

Partner with Granada

Sound and energy-saving performance

Whether your client is renovating or building from new, every property presents its own unique challenges. Let us assist you in finding the ultimate solutions whether tackling a noise ridden property or a listed building that needs to be modernised. Our products solve multiple client challenges at once, from sound proofing to heat retention and security.

Design assistance at every stage

We offer a fully managed solution from design to manufacture to installation. Our design experts provide CAD measurements for drawings as well as site visits from a dedicated account manager for advice. Our comprehensive range of products for even the most awkward spaces means never having to compromise on quality.

Partner with Granada

State of the art manufacturing

All our products are extensively tested, carefully assembled and backed by warranty meaning you’re able to fulfil your own commercial obligations. Our product quality is industry leading and our Sheffield manufacturing facility is controlled by us. Our installers are trained and accredited by us, usually above industry standard.

How Granada works for you
Quality products
Quality products
Fewer customer queries, simple to install, rigorously tested
Multiple design choice
Multiple design choice
Fully customised products, maximum customer options
Technical back-up
Technical back-up
Advice, technical support, on site technical visit by advisor
Full advisory service
Helpline for homeowner product, service or installation queries.
Full advisory service
Installation accreditation
Training and accreditation provided by us with technical site guidance.
Installation accreditation
10-year warranty
For all frames and glazing. British factory made, engineered to last.
10-year warranty

Commercial Business Support FAQ

Design, Construction and Technology, Sustainable Architecture.

Yes, we have an NBS Source account which architects can use to specify our products for their projects.

Our NBS account can be acessessed via the following link - https://source.thenbs.com/manufacturer/granada-secondary-glazing/q8X1pYeHreEbVu9D7v1EV4/overview.

Yes you can. However; timber shutters generally close tight to the outer window and unless the whole shutter assembly is moved forward to accommodate the secondary glazing, they will cease to function. They should be sealed and fixed shut using packing timbers and insulation material as necessary, allowing the secondary window to be fitted to a vertical frame member of the shutter. Avoid fixing across the panel.

Yes it is possible to have controls pass through the jamb of the secondary glazing but consideration needs to be given to the type of control e.g. wand, cord, or turn knob and assess whether an enlarged timber ground is needed to house the control and allow access for operation.

Secondary glazing is only suitable for treating french, patio, balcony doors etc. typically those which are used occasionally for access to an enclosed area. They are not suitable for treating front doors or main access to an enclosed area. They are not designed to be operated from the outside. Double doors can be fitted with either side hung casement or horizontal sliding units. Single doors can be fitted with side hung casement units. If the doors are inward opening, then full consideration needs to be given to clearances and it may be that the primary doors will no longer open to 90°.

Existing dry lined wall/reveals should be carefully examined to locate battens for key fixing points. Plasterboard fixings should be used at intermediate positions. Side hung units require particularly sound fixings at the hinge point and an enlarged structural timber sub frame may have to be considered to provide this strength. The design of any new dry lining should take into account the fixing requirements of the secondary window frames. A suitable steel channel or timber section acting as a sub frame should be set behind the plaster board at the fixing point off the secondary glazing where load is to be transferred. This sub frame may have to be tied back to the structure which is particularly important if side hung secondary windows are specified.

Yes, ideally the suspended ceiling bulk head needs to be finished within the window reveal and provide a suitable fixing position for the secondary glazing. If the suspended ceiling extends only to the wall face, then a timber batten can be added to the rear of the bulk head. Consideration must be given to the acoustic integrity of the bulk head, to avoid noise break through from the ceiling void.

The answer to this depends on many factors including; primary window clearances and styles, reveal conditions, appetite for the acceptance of restricted opening and the appetite for acceptance of structural modification. It would be best to contact us directly to discuss your requirements and possible solutions.

That will depend upon the projection of the primary window hardware and the available reveal. We often find in these situations that the primary hardware needs to be modified or removed to enable a secondary glazing treatment.

Ideally extractor fans should be removed and the primary window made good, as it will severely affect the performance of the secondary window if it remains. If however, the vent is required and secondary glazing is to be installed, then a suitably matched secondary vent should be fitted in the secondary glazing adjacent to the existing - see below.

This question is particularly relevant to vertical sliding secondary glazing as the stop positions on the balances will limit the travel, which in turn can limit access. The extent of the limited access will be dependent on the depth of cavity and how close the break line is to the center.

An odd leg frame and timber ground arrangement allows out of square openings to be dealt with discreetly. Enlarged or tapered grounds can be used to provide a true opening into which the secondary glazing is fitted. The enlarged timber grounds are finished to match the secondary glazing frame colour so that they blend in and require no post installation finishing.

The cill should support both the weight of the secondary glazing and of window cleaners without deflection. Large sliding panels could weigh more than 30 kg per meter run. Any movement of the cill will reduce the sealing efficiency of sliding panes and at worst, allow a panel to fall out of its frame. Deep cills or cill casings having cut outs for air grilles must have sufficient supports or inherent strength to accept these weights without deflection. Air grilles may also have to be repositioned to avoid them venting into the cavity formed by the secondary glazing.

The odd leg frame and timber ground arrangement allows for splay openings to be dealt with discreetly. Splayed grounds can be used to provide a true opening into which the secondary glazing is fitted. The enlarged timber grounds are finished to match the secondary glazing frame colour, so that they blend in and require no post installation finishing.

The odd leg frame and timber ground arrangement allows the use of faced fixed joinery sub frames to create a reveal. The face fixed sub frame is fully factory finished to match the secondary glazing frame colour and requires no post installation finishing.

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