Requirement

Site preparation and resistance to contaminants and moisture

Preparation of site and resistance to contaminants.

C1. (1) The ground to be covered by the building shall be reasonably free from any material that might damage the building or affect its stability, including vegetable matter, topsoil and pre-existing foundations.

  • Reasonable precautions shall be taken to avoid danger to health and safety caused by contaminants on or in the ground covered, or to be covered by the building and any land associated with the building.
  • Adequate sub-soil drainage shall be provided if it is needed to avoid:
    • the passage of ground moisture to the interior of the building;
    • damage to the building, including damage through the transport of water-borne contaminants to the foundations of the building.
  • For the purpose of this requirement, ‘contaminant’ means any substance which is or may become harmful to persons or buildings including substances which are corrosive, explosive, flammable, radioactive or

Resistance to moisture

C2. The walls, floors and roof of the building shall adequately protect the building and people who use the building from harmful effects caused by:

  • ground moisture;
  • precipitation including wind-driven spray;
  • interstitial and surface condensation; and
  • spillage of water from or associated with sanitary fittings or fixed

  1. Material Change of Use
    1. Historic Buildings

    Material Change of Use

    Requirement C1 (2), which addresses resistance to contaminants, is now added to the requirements in Regulation 6 of the Building Regulations 2010 which should be complied with when there are certain material changes of use of buildings.

    Regulation 6 sets out which parts of Schedule 1 should be complied with when there is a material change of use of the building as defined in Regulation 5. The absence of such a requirement would have meant that occupiers of  buildingsin areas at risk from contaminants may remain unprotected after the building work to effect the change of use is complete.

    In particular, some contaminants can penetrate the floors of buildings such as landfill gas arising from the deposition of waste and vapours from spills of organic solvents and fuel. These contaminants can also migrate laterally from land outside the building. In order to deal with this Requirement C1 (2) now applies to all changes of use that have a residential purpose or provide sleeping accommodation including hotels,  i.e. as defined by Regulation 5 (a) to 5 (g) with the exception of 5 (e) public buildings and 5 (j) shops. Other types of buildings are covered by Health and Safety legislation so do not need addressing through the Building Regulations, for example workplace assessment, including radon measurements.

    Attention is drawn to the following extracts from the Building Regulations 2010.

    Interpretation (Regulation 2)

    ‘Room for residential purposes’ means a room, or suite of rooms, which is not a dwelling-house or a flat and which is used by one or more persons to live and sleep and includes a room in a hostel, a hotel, a boarding house, a hall of residence or a residential home, but does not include a a room in a hospital, or other similar establishment, used for patient  accommodation.

    Meaning of material change of use (Regulation 5)

    For the purposes of paragraph 8 (1)(e) of Schedule 1 to the Act and for the purposes of these Regulations, there is a material change of use where there is a change in the purposes for which or the circumstances in which a building is used, so that after the change:

    1. the building is used as a dwelling, where previously it was not;
    2. the building contains a flat, where previously it did not;
    3. the building is used as a hotel or boarding house, where previously it was not;
    4. the building is used as an institution, where previously it was not;
    5. the building is used as a public building, where previously it was not;
    6. the building is not a building described in Classes 1 to 6 in Schedule 2, where previously it was;
    7. the building, which contains at least one dwelling, contains a greater or lesser number of dwellings than it did previously;
    8. the building contains a room for residential purposes, where previously it did not;
    9. the building, which contains at least one room for residential purposes, contains a greater
    10. or lesser number of such rooms than it did previously; or
    11. the building is used as a shop, where previously it was

    Requirements relating to material change of use (Regulation 6)

    1. Where there is a material change of use of the whole of a building, such work, if any, shall be carried out as is necessary to ensure that the building complies with the applicable requirements of the following paragraphs of Schedule 1:
    1. in all cases,
    • B1 (means of warning and escape)
    • B2 (internal fire spread – linings)
    • B3 (internal fire spread – structure)
    • B4 (2) (external fire spread – roofs)
    • B5 (access and facilities for the fire service)
    • C2 (2) (interstitial and surface condensation)
    • F1 (ventilation)
    • G1 (cold water supply)
    • G3 (1) to (3) (hot water supply and systems)
    • G4 (sanitary conveniences)
    • G5 (bathrooms)
    • G6 (kitchens and good preparation areas) H1 (foul water drainage)
    • H6 (solid waste storage)
    • J1 to J4 (combustion appliances)
    • L1  (conservation of fuel and power –dwellings);
    • P1 (electrical safety);
    1.  in the case of a material change of use described in Regulations 5(c), (d), (e) or (f), A1 to A3 (structure);
    2. in the case of a building exceeding fifteen metres in height, B4 (1) (external fire spread – walls);
    3. in the case of a material change of use described in regulation 5(a), (b), (c), (d), (g), (h), (i) or, where the material charge provides new residential accommodation, (f), C1 (2) (resistance to contaminents);
    4. in the case of material change of use described in regulation 5(a), C2 (resistance to moisture);
    5. in the case of a material change of use described in regulation 5(a), (b), (c), (g), (h) or (i), E1 to E3 (resistance to the passage of sound);
    6. in the case of a material change of use described in regulation 5(e), where the public building consists or contains a school, E4 (acoustic conditions in schools);
    7. in the case of a material change of use described in Regulation 5(a) or (b), G2 (water efficiency) and G3(4) (hot water supply and systems: hot water supply to fixed baths);
    8. in the case of a material change of use described in regulation 5(c), (d), (e) or (j), M1 (access and use).

    Where there is a material change of use of part only of a building, such work, if any, shall be carried out as is necessary to ensure that:

    • that part complies in all cases with any applicable requirement referred to in paragraph (1) (a);
    • in a case to which sub-paragraphs (b),
    • (e), (f), (g) or (h) of paragraph (1) apply, that part complies with the requirements referred to in the relevant sub-paragraph; and
    1. in the case to which sub-paragraph (c) of paragraph (1) applies, the whole building complies with the requirement referred to in that sub-paragraph; and
    2. in the case to which sub-paragraph (i) of paragraph (1) applies:
      • that part and any sanitary appliances provided in or in connection with that part comply with the requirements referred to in that sub-paragraph; and
      • the building complies with requirement M1 (a) of Schedule 1 to the extent that reasonable provision is made to provide either suitable independent access to that part or suitable access through the building to that part.

     

    Historic Buildings

    Material change of use or alterations to existing buildings may include work on historic buildings. Historic buildings include:

    1. listed buildings;
    2. buildings situated in conservation areas;
    3. buildings which are of architectural and historical interest and which are referred to as a material consideration in a local authority’s development plan;
    4. buildings of architectural and historical interest within national parks, areas of outstanding natural beauty and world heritage

    The need to conserve the special characteristics of such historic buildings needs to be recognised3. In such work, the aim should be to improve resistance to contaminants and moisture where

    it is practically possible, always provided that the work does not prejudice the character of the historic building, or increase the risk of long-term deterioration to the building fabric or fittings.  In arriving at an appropriate balance between historic building conservation and improving  resistance to contaminants and moisture it would be appropriate to take into account the advice  of the local planning authority’s conservation  officer.

    Particular issues relating to work in historic buildings that warrant sympathetic treatment and where advice from others could therefore be beneficial include the following:

    1. avoiding excessively intrusive gas protective measures;
    2. ensuring that moisture ingress to the roof structure is limited and the roof can breathe3,4. Where it is not possible to provide dedicated ventilation to pitched roofs it is important to seal existing service penetrations in the ceiling and to provide draught proofing to any loft hatches. Any new loft insulation should be kept sufficiently clear of the eaves so that any adventitious ventilation is not reduced.

    In most cases the rate at which gas seeps into buildings, mainly through floors, can be reduced by edge located sumps or sub-floor vents. These are less intrusive than internal sumps or ducts that may involve taking up floors. If flagged floors are taken up the stones should be indexed and their layout recorded to facilitate relaying when work is completed.

    Radon can be dispersed by ventilation strategies such as positive pressurisation. These systems can often be accommodated in an unobtrusive  manner.

    If internal mechanical ventilation is used to disperse ground gases, it may affect the functioning of combustion appliances and may lead to the spillage of products of combustion into the building. Guidance on this can be found in BRE Report BR 21175.