Replacement windows
Last updated | 07/11/2008
Do I need a building warrant to replace my windows?
In general a building warrant will not be required for replacement windows, however there are some exceptions, as follows:-
- The structural opening into which the window unit fits is being enlarged, or
- The structural opening into which the window unit fits is being reduced in size, or
- Where mullions are being removed
It has to be emphasised however that all replacement windows must be installed to comply with the current building regulations. If you require more information please contact your local Building Standards office.
What if I am changing the style of my windows?
If the new window(s) effectively matches the one(s) being removed, (for example if you have a double glazed unit that is defective and you are installing a direct replacement, then no building warrant is required).
If you are changing the style of the window(s), the work still does not require a building warrant but the new window(s) will require to meet the full requirements of the current technical standards. This will generally require a window which achieves a higher standard of thermal insulation, which is in line with Government commitment to saving energy and reducing emission of greenhouse gases. The benefit to you as householder will be reduction in your heating bills.
If you wish to find out more, the legislation that details the exemption is Regulation 5 together with Schedule 3 in Section 0 of the Building (Scotland) Regulations 2004. You can view this on the Scottish Building Standards Agency website at http://www.sbsa.gov.uk/
What are the main standards that my windows should be designed to meet?
Whether or not you require a building warrant, the following information draws your attention to the main technical requirements for windows
The opening area of the window(s) or aggregate thereof should be no less than 1/30th of the room floor area, unless a suitable mechanical ventilation system is in place.
A trickle ventilator should be installed in the window head, such that an apartment e.g. living room, bedroom,study is provided with 8000mm² of trickle ventilation, all other accomodation e.g. Kitchen, Utility room, Bathroom, Shower room, toilet require 4000mm²
The glazed area of the window(s) or aggregate thereof, to all apartments
- i.e. livingroom, bedroom, study, dining room etc, must be not less than 1/15th of the room floor area.
- Where any parts of your window(s) are 4 metres or more above ground level, the external surface of the glass requires to be safely cleanable from within.
- In apartments (bedrooms, livingrooms, diningrooms, studies etc) situated on an upper storey which is less than 4.5 metres above ground level, there must be an emergency escape window. Such windows require to have an unobstructed opening area of not less than 0.33m² with dimensions at least 450mm high and 450mm wide. The bottom of the opening of such a window must be no greater than 1.1 metres from floor level.
The glazing units require (from 01/05/07) to have a U value as per the following chart-
Frame Type | U Value with High efficiency gas/oil heating system | U Value with Other gas/ oil system or electric system |
|---|
| upvc/ wood |
1.8 |
1.8 |
| metal |
1.8 |
1.8 |
Window energy rating band D is acceptable as an alternative to U value 1.8
