Guide to Building Control For Domestic Buildings

To clarify the practical requirements of the Building Regs and help you meet their requirements first go, all the information contained in the building regulations 2010 and approved documents is presented here in an easy-to-understand format, clear, concise and fully illustrated.

Guidance is given for domestic buildings of up to three storeys in England and Wales, including extensions, loft conversions, new dwellings, conversions (garages, basements and barns), and upgrading of existing buildings - including the use of natural lime mortars, plasters renders and paints. There are clear explanations of how the technical design and construction requirements of the Building Regs can be met with sufficient information to draw up an effective specification and design to be developed.

Guide to Building Control illustrates the design and construction of the various building elements and explains the principles and processes of the building regulations and approved documents - including structure, fire safety, contaminates, sound insulation, ventilation, water efficiency, drainage systems, combustion appliances, stairs and guarding, energy conservation/green building issues, disabled access, safety glazing, electrical safety, materials and workmanship.

The Guide contains up-to-date examples of everyday practices and procedures gained by the author - a practicing building control surveyor - from years of responding to requests from property professionals, builders, property owners and students for clarification of the practical requirements of the building regulations.

Accompanied by detailed diagrams, tables and text offering an enlightened understanding of the complexities of building regulations the Guide is both an authoritative reference for use at planning stage and a practical handbook on site.

About the Author xi

Acknowledgements xiii

Notes to the Reader xv

Expected Changes to the Building Regulations to Come into Force in 2013 xvii

Section 1 General information 1.1

Introduction 1.3

The Building Act 1984 and the Building Regulations 2010 1.3

Approved Documents 1.4

Other ways of satisfying the Building Regulations requirements 1.5

Technical and condensation risks 1.5

Timber-sizing tables independently calculated by GEOMEX for solid timber members 1.6

Engaging a property professional 1.6

Obtaining Building Regulations approval 1.7

Notices of stages of works 1.9

Exempt buildings and work 1.9

Preliminary works 1.11

Matters related to the Building Regulations 1.14

The Party Wall Act 1996 1.15

Rights of Light 1.17

Section 2 Domestic extensions 2.1

Part A: Structure 2.9

A1: Sub-structure 2.9

Foundations 2.9

Ground floors and sub-structure walls 2.18

A2: Superstructure 2.28

Minimum headroom heights 2.28

External walls 2.28

External cavity wall construction 2.35

Lateral restraint strapping of upper floors to walls 2.49

Lateral restraint strapping of roofs to walls 2.51

Lateral restraint strapping of walls at ceiling level 2.52

A3: Separating walls and floors 2.53

Masonry party walls separating dwellings 2.53

Double-leaf timber-frame party walls separating dwellings 2.54

A4: Internal partitions 2.56

A5: Intermediate upper floor(s) 2.56

Floor joists 2.56

Trimming and trimmer joists 2.58

A6: Pitched roofs 2.60

Pitched roof coverings 2.61

Pitched roof structure 2.62

A7: Flat-roof construction 2.70

Option 1: Flat roof with ‘cold deck’ 2.70

Option 2: Flat roof with ‘warm deck’ 2.72

Option 3: Flat roof with inverted ‘warm deck’ (insulation on top of waterproof coverings) 2.74

Option 4: Flat roof with green roof on ‘warm deck’ (either intensive or extensive) 2.74

The design, workmanship and selection of materials for flat roofs 2.75

A8: Mortars, renders and gypsum plasters 2.75

Cement mortars and renders 2.75

Gypsum plasters 2.77

Part B: Fire safety and means of escape 2.78

Fire detection and fi re alarm systems 2.78

Means of escape 2.79

Surface spread of flame: internal wall and ceiling linings including roof lights 2.89

Part C: Site preparation and resistance to contaminants and moisture 2.92

C1: Resistance to contaminants 2.92

Radon gas 2.93

Methane and other ground gas protection 2.96

C2: Resistance to moisture 2.96

Part D: Cavity wall filling with insulation 2.98

Part E: Resistance to the passage of sound 2.98

Part F: Ventilation 2.99

Purge (natural) ventilation 2.99

Mechanical extract ventilation and fresh air inlets for rooms without purge ventilation 2.99

Background ventilation 2.100

Intermittent mechanical extract ventilation 2.100

Part G: Sanitation, hot-water safety and water efficiency 2.100

Wholesome hot and cold water supply 2.100

Solar water heating 2.102

Electrical water heating 2.102

Insulation of pipework to prevent freezing 2.102

Supply (Water Fittings) Regulations 1999 2.103

Part H: Drainage and waste disposal 2.103

H1: Foul- and storm-water drainage 2.103

H2: Septic tanks, sewage treatment systems and cesspools 2.113

Septic tanks 2.113

Sewage treatment systems 2.114

Percolation tests 2.116

Cesspools 2.118

H3: Rainwater drainage and harvesting 2.119

H4: Building over or close to, and connections to, public sewers 2.122

Building over or close to a public sewer 2.122

Connections to public sewers 2.123

H5: Separate systems of drainage 2.124

H6: Solid waste storage 2.124

Part J: Combustion appliances and fuel storage systems 2.124

Solid fuel appliances up to 50 kW rated output 2.125

Appliances other than solid fuel 2.133

Fuel storage tanks 2.134

Renewable energy/micro regeneration installations 2.134

Part K: Protection from falling, collision and impact 2.135

Internal stairs, guarding and landings for changes in level of 600 mm or more 2.135

External stairs, guarding and landings for changes in level of 600 mm or more 2.138

Loft conversion stairs 2.139

Ramps 2.140

Part L: Conservation of fuel and power in existing dwellings 2.141

Areas of external windows, roof windows and doors 2.141

New thermal elements 2.141

Energy-efficient lighting 2.143

Insulation of pipework to prevent freezing 2.143

External walls, roofs, floors and swimming-pool basin 2.143

Renovation/upgrading of existing thermal elements 2.144

Part M: Access to and use of buildings for disabled 2.145

Part N: Safety glazing, opening and cleaning 2.146

Safety glass and glazing 2.146

Part P: Electrical safety 2.147

Electrical installations 2.147

External works – paths, private drives, patios and gardens 2.149

Section 3 New dwellings 3.1

Parts A and L: Starting point 3.4

Conservation of fuel and power in new dwellings 3.4

Criterion 1 – Achieving the Target Emission Rate (TER) 3.4

Criterion 2 – Limits on design flexibility 3.5

Criterion 3 – Limiting the effects of solar heat gain 3.5

Criterion 4 – Calculation of the Dwelling Design Emission Rate (DER) 3.6

Criterion 5 – Provision for energy-efficient operation of the dwelling 3.10

Insulation guidance details for floors, walls and roofs 3.10

Guidance on the Code for Sustainable Homes for new dwellings 3.12

Guidance on PassivHaus 3.18

Part B: Fire safety and means of escape 3.19

Part C: Site preparation and resistance to contaminants and moisture 3.20

Part D: Cavity wall filling with insulation 3.20

Part E: Resistance to the passage of sound 3.20

Part F: Ventilation to new dwellings 3.21

Ventilation systems 3.21

Purge (natural) ventilation to habitable rooms: system 1 – new dwellings 3.22

Background ventilation: system 1 – new dwellings 3.23

Intermittent mechanical extract ventilation: system 1 – new dwellings 3.24

Part G: Sanitation, hot-water safety and water efficiency 3.24

Part H: Drainage and waste disposal 3.25

Part J: Combustion appliances and fuel storage systems 3.26

Part K: Protection from falling, collision and impact 3.26

Part L: Conservation of fuel and power 3.26

Part M: Access to and use of buildings for disabled 3.26

Guidance on Lifetime Homes Standard for new dwellings 3.31

Part N: Safety glazing, opening and cleaning 3.32

Part P: Electrical safety 3.32

Section 4 Domestic loft conversions 4.1

Converting an existing loft space 4.3

Assessing the feasibility of your loft for conversion 4.3

Part A: Structure 4.5

A1: Inspection of the existing roof and building structure 4.5

A2: Alteration, modification and strengthening of the existing roof structure 4.5

A3: Roof conversion details 4.5

Upgrading existing external walls 4.5

Internal load-bearing timber stud walls 4.7

Part B: Fire safety and means of escape 4.11

Single-storey dwellings with loft conversion 4.11

Two-storey dwellings with loft conversion (or new third storey) 4.13

Part C: Site preparation and resistance to contaminants and moisture 4.17

Part D: Cavity wall fi lling with insulation 4.17

Part E: Resistance to the passage of sound 4.17

Part F: Ventilation 4.17

Part G: Sanitation, hot-water safety and water efficiency 4.17

Part H: Drainage and waste disposal 4.17

Part J: Combustion appliances and fuel storage systems 4.17

Part K: Protection from falling, collision and impact 4.17

Part L: Conservation of fuel and power in conversions 4.17

Part M: Access to and use of buildings for disabled 4.18

Part N: Safety glazing, opening and cleaning 4.18

Part P: Electrical safety 4.18

Section 5 Domestic garage and basement conversions into habitable rooms and conversion of barns and similar buildings into new dwellings 5.1

Assessing the feasibility of your building for conversion 5.6

Part A: Structure 5.14

A1: Underpinning works 5.14

Traditional underpinning 5.14

Sections through proposed underpinning (not to scale) 5.15

A2: Single-wall garage conversions (or similar buildings) into habitable rooms (typical details indicated in Figures 5.2–5.12) 5.16

Upgrading pitched roofs 5.16

Upgrading flat roofs 5.19

Infilling of garage door openings 5.20

Upgrading single-skin external walls 5.21

Upgrading garage ground floors (or similar) with upgraded enclosing single-skin walls 5.26

A3: Cavity wall garage conversions (or similar buildings) into habitable rooms (typical details indicated in Figures 5.16–5.26) 5.29

Upgrading pitched roof 5.29

Infilling of garage door opening 5.31

Upgrading external cavity walls 5.33

Upgrading garage ground floors (or similar) with enclosing upgraded cavity walls 5.34

A4: Basement conversions into habitable rooms 5.38

Existing basements and tanking systems 5.38

A5: Conversion of barns and similar buildings into new dwellings – Technical and practical guidance 5.40

Part A: Structure 5.40

Part B: Fire safety and means of escape 5.51

Part C: Site preparation and resistance to contaminants and moisture 5.51

Part D: Cavity wall filling with insulation 5.51

Part E: Resistance to the passage of sound 5.51

Performance standards 5.51

Part F: Ventilation to new dwellings 5.52

Part G: Sanitation, hot-water safety and water efficiency 5.52

Part H: Drainage and waste disposal 5.53

Part J: Combustion appliances and fuel storage systems 5.53

Part K: Protection from falling, collision and impact 5.53

Part L: Conservation of fuel and power in conversions 5.53

Energy Performance Certificate (EPC) 5.53

Part M: Access to and use of buildings for disabled 5.53

Part N: Safety glazing, opening and cleaning 5.54

Part P: Electrical safety 5.54

Section 6 Upgrading old buildings using lime and modern applications 6.1

Upgrading old buildings using lime and modern applications 6.3

Re-pointing and repair of existing buildings 6.4

Types of lime mortar, lime render/plaster and decorative finish suitable for breathable buildings 6.10

Index I.1

Tony Gwynne, a Building Control Surveyor, working for a District Council; 20 years experience at a senior level in local authority building control.