Amendments to the Building Regulations December 2004
Main changes to Approved Document A (Structure) and Approved Document C (Site preparation and resistance to contaminants and moisture.)
Use of Guidance
(a) Eurocodes: an announcement is given regarding the forthcoming introduction of the Structural Eurocodes and their National Annexes.
(b) House Construction: reference is made to the intended publication of guidance by industry of alternative forms of house construction to that of traditional masonry.
Approved Document A
A1 and A2
Traditional dwellings
(c) The guidance of the sizing of timber floors and roofs for traditional house construction has been removed as the timber tables are now published by TRADA. However, the TRADA tables are referenced under section 2B.
(d) A revised map of basic wind speeds in accordance with BS:6399:Part2 replaces the superceded map which was based on BS CP3 Chapter V.
(e) Stainless steel cavity wall ties have been specified to all houses regardless of their location.
(f) The guidance on masonry walls to dwellings has been extended to enable the rules to be applicable when using either the appropriate British Standards or the emerging BS EN CEN Standards.
(g) The guidance on concrete foundations to houses has been revised to align with the recommendations given in the British Standards and other authoritative guidance. Recommendations on minimum foundation depths have also been included to counter the impact of predicted climate changes.
(h) The guidance on the design and construction of domestic garages has been extensively updated to reflect modern practice.
A3
(i) Disproportionate collapse: The Application Limit to the Requirement (ie the 5 storey limit) has been removed so as to bring all buildings under control of the A3 Requirement.
The modified guidance has been developed from commissioned research and consideration of the recommendations given in the forthcoming Eurocodes EN1991-1-7 on Accidental Actions.
C1 Site preparation and resistance to contaminants
Site preparation
(a) Site investigation is now recommended as the method for determining how much unsuitable material should be removed.
Resistance to contaminants
(b) Requirement C1(2) now applies to material change of use as set out in Regulation 5 and 6.
(c) Remedial measures for dealing with land affected by contaminants have been expanded to include biological, chemical and physical treatment processes.
(d) The area of land that is subject to measures to deal with contaminants now include the land around the building.
(e) Guidance on protection from radon is expanded to include buildings other than dwellings.
Sub-soil drainage
(f) Guidance is included relating to subsoil drainage and the risk of transportation of water-borne contaminants.
C2 Resistance to moisture
(g) New guidance recommends that in order to reduce the condensation risk to floors, walls and roofs reference should be made to the revised BS 5250 and "Limiting thermal bridging and air leakage: robust details" and BRE 262 "Thermal insulation: avoiding risks."
(h) Guidance is now provided on the use of moisture resistant boards for the flooring in bathrooms, kitchens and other places where water may be spilled from sanitary fittings or fixed appliances.
(i) Reference is made to BS 8208 for assessing the suitability of cavity walls for filling together with the map and table in BR 262.
(j) Interface between walls and doors and windows. Check rebates are now recommended in the most exposed parts of the country.
(k) New guidance points to the need for better attention to detail in exposed areas where level access is provided to support Part M, Access to and use of buildings to ensure adequate provision is made for resistance to moisture.
(l) Former Requirement F2; Condensation in roofs, has been transferred to Part C as it deals with effects on the building fabric rather than ventilation for the health of occupants.
iCM