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No matter what type of property you are building or adding to, there are key issues that should always be considered when procuring and fitting windows and doors.

You’ll need to ensure that they are being fitted to a supportive surround, can hold heavy structural loads and feature appropriate weather sealing to prevent drafts and water entering properties.

To ensure you get it right, we’ve created a handy checklist for new builds and period properties:

New builds

  • Are there support features at the base of the new windows and doors?
  • Are the surround structures for the new windows and doors capable of taking the wind loads from the products at the fixing positions, especially for large units?
  • Has a weatherseal between the window and door units and external structures been applied?
  • Has an air seal or vapour barrier between products and the internal structures of the building been applied to reduce air and heat loss?
  • Are the window and doors fixed at fixing centres provided by the manufacturer or in accordance with BS 8213?
  • Are the windows or doors very large? If they are, the structural opening may need to be divided with additional steel posts and/or beams to provide the right level of support to    the units to resist high wind loads. 

Good to know:

High winds can be very destructive in the construction of properties, as they generate pressure against the surface of a structure. The intensity of this “pressure” is called the wind load. The effect of the wind is dependent on the size and shape of a building, and calculating wind load is necessary for the design and construction of a safe, wind-resistant building.

To calculate wind load you need to review the projected area of the building, against the typical wind pressure of the location.

Period properties

  • Are you fitting punched hole windows? Is there a secure support for the structure above the lintels and cavity trays?
  • Does the building have signs of movement such as cracks in mortar joints? These will need to be corrected before fitting new window and door units.
  • Does the property have traditional bay window features? These often bear a load directly above, so double check this when procuring new windows and ensure extra support such as steel posts at facet or corner junctures are used.
  • Have you reviewed the perimeter seals before fitting new windows? Certain types of stone work may not be compatible for expanding foam seals and a silicone seal may be needed as a priming agent.
  • Have you determined the setback of your windows and doors? It’s best practice to establish the overall thickness of the reveal first.
  • Have you checked for existing signs of damp and water ingress? This may reveal structural problems as opposed to existing window seal breakdown.
  • Is the facade in a general good condition? Do stone sills and lintels have cracks or fissures?

TOP TIP: Rationel products are non-load bearing.


Best practice for the layout of windows and doors

  • Lifetime Homes advise that people should be able to see out of a window when seated in living room areas, and glazing should begin at 800mm or lower on at least one                      window.
  • Position windows east to west to take advantage of early morning and afternoon solar heating.

To discover how you can benefit from our help, simply get in touch by calling a member of our team on 01869 248181, or email generalenquiry@rationel.co.uk.


Alternatively, click here to download our brochure.