As we’ve seen in previous months, even seemingly simple projects like replacing a fire door, removing a non-load-bearing wall, improving thermal insulation, installing new windows or the modernization of a boiler are regulated. But what do you have to comply with?

At the heart of the building regulations is Annex 1, which now contains 18 technical requirements. The first thing to do when looking at compliance is to look at Appendix 1 and look for “Application Limits”.

Some of these technical requirements may not apply to your project. For example, part G2 (requirement relating to water consumption calculations) only applies when creating a dwelling; while Part K5 does not apply to homes, so you will not need to provide a manifestation in the form of a visible strip on the patio doors of a house to prevent people from entering the glass . Another example is that the newly introduced Part T1 does not apply to schools, so there is no requirement for single-sex toilets in these.

The next step is to check what technical requirements are required by the type of work you are doing. For example, where a significant change of use takes place, Regulation 6 only calls for specific parts of Schedule 1. See the table below to see how these are applied.

Table A2

Next, you need to check Regulation 7, which requires all building work to be carried out using adequate and suitable materials and in a professional manner. It is important to note that this provides additional restrictions for “relevant buildings”, for example those with one storey more than 18m in height and containing one or more dwellings, institutions or rooms for residential purposes (NB: it is This is a slightly different definition than tall buildings, so don’t be surprised!)

Let’s say you’re considering adding an extra floor to a building. The building comprises apartments over three floors and is extended by an additional floor, transforming it into four-storey apartments. The building will not exceed 11 m in height. This is considered ‘construction work’ under the regulations, so all applicable regulations must be considered for the new floor. In addition, the entire structure will need to be checked to ensure that once the work is completed, it still complies with the relevant requirements if it previously complied, or is no longer unsatisfactory if it did not. not before.

Rule 5 – significant change of use category (g) – applies as there will be more dwellings than before. But if you look at the table you will see that Regulation 6 does not require work to be carried out to ensure compliance with Part A3 (disproportionate collapse).

Now let’s look at essentially the same project, but this time adding a fifth floor to a four-story building, meaning the building will now be over 11 m² in size. Similar to the first example, Regulation 5 applies because the addition of a new storey constitutes construction work (an extension).

Again, Regulation 6 does not require specific work to ensure compliance with Part A3. However, Regulation 4 still requires an assessment to see if compliance has been affected. It is important that construction works comply with A3. In this case, due to the additional floor, the consequence class changes from CC2a to CC2b, and stricter measures are necessary. The increased height means you may need to reinforce the entire lower structure to ensure it meets the increased requirements of a five-storey building in terms of structural integrity and resistance to collapse .

Additionally, the extension means the building will now exceed 11m in height, and regulation 6(3) requires external walls to use materials rated A2-s1, d0 or A1. Additionally, the building will now require sprinklers as it exceeds the sprinkler trigger height, and wayfinding signage is required for fire services.

You can infer that two very similar projects may have extremely different requirements and costs.

Geoff Wilkinson is Managing Director of Wilkinson Constructions Consultants and a Class 3G and 3H Registered Building Inspector. He runs the AJ’s building safety masterclasses in November.