BuildingRegs4Plans Premium
Register Now to Access our Library of Building Regulations Specifications and 540+ Detail Drawings for Extensions, Loft Conversions, Flat Conversions, Garage Conversions, Garage Builds and New Builds
Follow BuildingRegs on Twitter
Building Regulations Notes for Plans - A Step Beyond Guidance
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
Window/Door
Structure Details
Drainage Details
Timber Frame
Guidance - Flat Roof Types

Flat Roof - Types

Introduction

  • A roof is defined in BS 6229 as a flat roof if it has a pitch of 10 degrees or less.
  • A flat roof must be strong, durable and stable throughout its lifetime. It must provide adequate protection against the elements, keeping the buildings structure and interior dry.
  • Flat roofs have a reputation of failing early but improvements in strength, flexibility, ageing and weather resistance mean that, if built with care, using the correct materials, today’s high performance felts can have a life span of up to 20 years.

Roof Types

Flat roof constructions are generally classed as either ‘Cold’ or ‘Warm’ roofs depending on the position of the thermal insulation.

The Cold Roof

Cold Flat Roof
  • Although not recommended today, and actually banned in Scotland, until recently cold flat roofs were fairly common.
  • In a cold roof the thermal insulation is laid between the joists below the structural deck.
  • As the insulation is not required to take any loads, quilts and other loose fill materials can be used as well as rigid insulation.
Click Image for Low-Res Preview
Cold Flat Roof Detail, Felt Covering
£2.50 + vat
Add To Basket
Includes DXF,
DWG and Jpeg
  • Because the structural elements of a cold roof are not protected by from the heat of the sun by a layer of insulation they are liable to suffer the damaging effects of thermal movement.
  • Ventilation is required above the insulation in a cold roof to prevent the build up of moisture vapour in the roof void.
A Selection of Detail Drawings by Categories. This is just a Small Sample from our Drawing Library.
Instead of purchasing drawings individually, register for a BuildingRegs4Plans Premium account? Login to access 540+ detail drawings. Most details linked to our Building Regs Specifications.

New Detail Drawings here, including Mansard Roof Edge, Box Gutter, Parapet Wall, Window Frame, Window Sill, Window Lintel, Joist Hangers, Joist Built into Wall, Hearth, Drainage Pipes, Pipe through Wall, Stairs and Loft Stairs.

Warm Deck Roof

Warm Flat Roof
  • In a warm deck roof the insulation is positioned above the structural deck and no ventilation is required.
  • Throughout the course of the year the roof deck and all below it is kept at a temperature close to that of the inside of the building, therefore the roof structure is protected from extremes of hot and cold, lessening the potential for damage caused by thermal movement.
Click Image for Low-Res Preview
Warm Flat Roof Detail, Felt Covering
£2.50 + vat
Add To Basket
Includes DXF,
DWG and Jpeg
  • A warm deck also provides added protection from the dangers of condensation as the structure is kept warm, at a temperature above dewpoint, by the insulation above it. Therefore water vapour which enters the roof structure from the room below will not have a cold surface on which to condense. NHBC recommend that this type of roof be considered as the standard form of construction.

Types of Warm deck roof

There are two forms of warm deck roof:

  • Sandwich
  • Inverted

Warm Deck: Sandwich Roof

  • The sandwich warm deck roof is the most common type of flat roof. The insulation is placed below the waterproof covering and is either mechanically fixed or bitumen bonded on to the top of the deck.

Inverted warm deck roof

  • The insulation boards in an inverted warm deck are laid over the structural deck and the waterproof covering. The insulation is secured by a layer of ballast or paving slabs to prevent wind uplift.
  • The waterproofing membrane has the added protection of the insulation from foot traffic and degradation caused by exposure to solar radiation. However, it may be a more difficult to locate defects in the membrane.
  • Proprietary systems are available now which combine the insulation and ballast layers.

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
Basket
Compile your Building Regs Specification
House Extension
Loft Conversion
Flat Conversion
Garage Convers'n
New Build
Garage Build
Registered Users
Register
Login
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
A Step beyond Building Regulations Guidance for Building Control Plans in England and Wales
Specifications for House Extension, New Build, Flat Conversion, Loft / Garage Conversion and Garage Build Plans for Building Control - Construction Notes & Guidance
Building Regulations Specifications for Submission to Approved Inspectors
For info on the October 2015 Building Regulations changes click here
Syspec LtdCompany No. 8742551VAT Reg No. 241 8003 43
Copyright © 2016 BuildingRegs4Plans