Streamline your Building Regs Specifications
with our Premium service
Register Now for our Library of Building Regs Specifications & 750 Detail Drawings for Extensions, Loft Conversions, Flat Conversions, New Builds, Garage Conversions, Garage Builds, New Build Flats & Basement Conversions
Building Regs Notes for Plans - Beyond Guidance
Follow BuildingRegs on Twitter
Building Regs Specifications & Detail Drawings
Beyond Building Regulations Guidance. Construction Specifications for House Extensions, New Builds, Flat Conversions, Loft Conversions, Garage Conversions and Garage Builds.
Detail Drawings
New Details
Foundation Details
Floor Details
Wall Details
Roof Details
Internal Works
Structure Details
Drainage Details
Timber Frame
Loft Conversions
Garage Conversion
Basement Conversion
Register now for BuildingRegs4Plans Premium!
Includes access to 750+ Detail Drawings
Plus our online library of Building Regs Specs
New Builds
Garage Builds
New Build Flats
Flat Conversion
Guidance - Pitched Roof - Overview

Pitched Roofs - Overview


The function of a roof is to protect the building below from the weather. In order to satisfactorily fulfil this function over a period of years it must be strong, stable and durable.

In addition, roofs must provide good thermal insulation and prevent the spread of fire from adjacent or adjoining properties.

Click Image for Low-Res Preview
Pitched Roof Detail, Ceiling-Level Insulation
£2.50 + vat
Add To Basket
Includes DXF,
DWG and Jpeg
  • The majority of houses in this country are constructed with pitched roofs.
  • The angle of the pitch may be dictated by aesthetic or structural factors.
  • It may also be influenced by the nature of the roof covering.
  • Modern tiles permit shallow pitch but some of the older traditional coverings, such as hand made clay tiles, require quite steep slopes to ensure rain does not penetrate the roof covering.
  • Shallow pitches are generally cheaper to construct with savings in both timber and tiling.
  • In traditional pitched roofs, the rafters are supported by a wall plate at the bottom and a ridge board at the top.
  • Intermediate support is supplied by a horizontal purlin.
  • Most modern roofs for new houses are built from prefabricated components erected on site.

Lean-to Roofs

The simplest of pitched roofs is the Lean-to roof, commonly found forming the rear extensions to terraced housing.

  • The sloping timbers are known as rafters and are supported at the top by building them into the solid wall (not recommended nowadays) and at the bottom by securing to a wall plate.
  • The wall plate is a strip of timber which is bedded in mortar on top of the wall, and which evenly distributes the load from the roof and provides a good fixing for the rafters.
  • Note: Mortar cannot actually bond the timber to the wall.
  • The wall plate should be 100mm x 75mm 0r 100mm x 50mm.
  • Ceiling joists are often built into the wall or supported on a wall plate bedded within the wall (not recommended).
  • The rafters are skew nailed to the plate
  • The depth of the rafter depends on its span and loading, and the width is primarily to prevent twisting and to provide a sufficiently wide surface on which to nail the battens supporting the tiles
  • It is good practice to notch the bottom of the rafter where it sits on the plate as this gives a good bearing and aids alignment of the rafters.
  • The rafters are usually spaced at 400mm centres.
  • In most houses, the guttering is supported by the facia board. This is fixed to the feet of the rafters and it can be flush against the wall or it can form an overhang.
  • Lean-to roofs can achieve only modest spans.

BuildingRegs4Plans Building Regulations Specifications

BuildingRegs4Plans Web Apps save Architects, Designers and Surveyors hours! Our 5 web apps provide precompiled Building Regs Specifications that can be compiled into a custom specification for your Building Projects.

Checkout our Building Regs Specifications Web Apps here:

House Extension Specifications for Construction Plans
Loft Conversion Specifications for Construction Plans
Flat Conversion Specifications for Construction Plans
Garage Conversion Specifications for Construction Plans
New Build Specifications for Construction Plans
Garage Build Specifications for Construction Plans
New Build Flats Specifications for Construction Plans
Basement Conversion Specifications for Construction Plans

To begin compiling your Building Regulations Specification with our App, choose either House Extension, New Build, Flat Conversion, Loft Conversion. Garage Conversion, Flat Conversion or Garage Build.

Construction Specifications for Home Extension, New Build, Garage Build, Loft, Flat & Garage Conversion Plans
Advice & Guidance
Go To Basket
Compile your Building Regs Specification
House Extension
Loft Conversion
Flat Conversion
Garage Convers'n
New Build
Garage Build
New Build Flats
Basement Conv'n
Home Extension Manual
House Front Elevation
Foundation Detail
Foundation Detail
Building Regulations April 2014 Changes
Part L1a
New Build
Flat Conversion
Garage Conversion
Loft Conversion
Garage Build Notes Added