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    Building Regulations Part A
    Everything you need to know about structure

    arrow Back to blog 16th May 2017

    What is Building Regulation Part A focused on? Put simply, building regulations Part A is focused on the structure and stability of a building. Essentially, it’s there to ensure that the building stays upright, even in the event of any impact. It’s focused on ensuring that the foundations of the building can deal with the ‘load’ imposed by the structure itself. The strength and stability of the ground in terms of supporting the foundations and the structure is also covered.

    There are two main principles to Building Regulations Part A (though obviously the regulation itself is very in-depth):


    This specifies that the building shall be constructed so that the combined dead, imposed and wind loads are sustained and transmitted by it to the ground in a safe way, and in a way that prevents deformation or instability in the structure.


    This specifies that the building shall be constructed so that the ground movement caused by swelling, shrinkage or freezing of the subsoil or land-slip or subsidence does not impair the stability of the structure.

    Other notable points

    The full document is 44 pages long, so we’re obviously not going to cover the whole thing here. However, we’ve been able to pull out the main points that relate to skylights.

    Openings, recesses, overhangs and chases

    It’s a legal requirement that the number, size and position of openings and recesses should never affect the stability of a wall or the lateral restraint afforded by a buttressing wall to a supported wall. Essentially, any opening must not impact the stability of the property.


    (Though less relevant to skylights, it’s also worth noting that no openings should be provided in walls below the ground floor except for small holes for services and ventilation.)

    Small single-storey non-residential buildings and annexes

    In these properties, one or two major openings of not more than 2.1m in height are permitted in one wall of the building or annexe only. The width of a single opening or the combined width of two openings cannot exceed 5m. The only other permitted openings in a building or annexe are traditional windows and a single leaf door.

    Section 4: Roof covering

    This is the main section that could potentially impact on skylights, as it applies to the roof area, so we’ll go through the relevant points here:


    All materials used to cover roofs, excluding windows of glass in residential buildings with roof pitches of not less than 15 degrees, need to be capable of safely withstanding the relevant roof loads as specified in the BS EN 1991-1-1:2002.


    If a roof undergoes re-covering, the structural integrity of the roof should be checked to ensure that when the work is complete the roof is no less compliant with Requirement A1 than it was before the work began.


    If the loading upon a roof is increased by 15%, then this will be classed as a significant change in the loading.


    If, once checked, the roof is deemed to be unable to sustain any potential increase in loading, additional strengthening work must be carried out before any further work is undertaken. (This will be classed as material alteration.)


    Where work significantly decreases dead loading, the roof structure and anchorage should still be checked to ensure that the safety factor is adequate to deal with uplift of the roof against imposed wind loading.


    (It’s worth noting that we’ve not covered 4.2 and 4.6, because they aren’t as relevant to our topic and – in the case of 4.2, it’s actually just a note about the other clauses under section 4!)

    Get in touch

    Remember that if you’re at all unsure about how Building Regulations might affect your skylight, you can always give Sunsquare a call. We’re specialists in ensuring projects go swimmingly, and can ensure you stay in line with any necessary legislation, allowing you to start enjoying your new rooflight.

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    Call us on 01922 714087

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