Built up roofing (RBM) waterproof membrane roofing systems insulation - thicknesses and Part L and Part B of Building Regs

This standard covers the knowledge and skills to understand insulation flat board and tapered and the importance of Building Regs Parts L and B.

CITB has developed this standard in discussion with industry


Minimum 1 day of 6 learning hours

Purpose / scope

The purpose of this standard is to provide the candidate with the knowledge and skills to understand insulation flat board and tapered. To understand the importance of Building Regs Parts L and B.

The scope of this standard covers:

  • types of insulation
  • thicknesses of insulation
  • insulation fire ratings
  • insulation and Part B of Building regulations
  • insulation and Part L of Building regulations.

Occupational relevance

Training delivered against this standard is relevant to the following occupational group(s):

  • operative and craft
  • supervision
  • management.

Candidate prerequisites

There are no candidate pre-requisites as part of this standard. However, a basic knowledge of built up roofing terminology and techniques would be beneficial.

Before candidates perform the work on a construction site, candidates must have successfully completed roofing-specific training for working at heights

Instruction / supervision

As a minimum, course instructors must be able to demonstrate that, in relation to this standard, they have:

  • A train the trainer or instructional techniques course certificate
  • Successfully completed training to this standard 
  • At least 2 years relevant industrial experience
  • A verifiable CV.


The following methods may be used in the delivery of this standard:

  • classroom and / or workshop

All materials and equipment must be of a suitable quality and quantity for candidates to achieve learning outcomes and must comply with relevant legislation.

The class size and candidate/instructor ratio must allow training to be delivered in a safe manner and enable candidates to achieve the learning outcomes.

This standard is considered to contain 51 per cent or more practical learning.

This standard is considered to be set at an intermediate level.


For the successful completion of training, candidates must complete an end of course practical assessment or knowledge test that measures the learning outcomes and has a pass or fail criteria.

Quality assurance


Quality assurance against this standard will require initial approval of the training organisation and their content mapped to the standard. 

CITB will also conduct an approval intervention, either desk-based or centre visit, to ensure the training organisation can meet the requirements of the training standard. 

Approved training organisations (ATOs) will be required to present information on records of training and assessment upon request to CITB for desk based analysis. They will also be visited annually by the CITB quality assurance team.


There are no mandatory renewal or recommended refreshment requirements for this standard.

Approval date


Review cycle

Either on request or in 3 years from approval date.

Learning outcomes

The candidate will be able to Additional guidance to support learning outcome
Describe the different types of flat roof insulation and their uses
  • PUR
  • PIR
  • Wool fibre
Visual slides in classroom

Group discussion
Describe how different thicknesses affect the U Value
  • What is a U value
  • Where would l need to U value

Visual slides in classroom

Group discussion

Describe the connection between insulation and Part L
  • Understanding of Part L
  • Part L1 A
  • Part L1B
  • Part L2A
  • Part L2B
Visual slides in classroom

Group discussion

Describe the connection between insulation and Part B
  • Understanding of Part B
Visual slides in classroom

Group discussion

Additional information about this standard

Health and Safety Executive (HSE)

British standards

View all available British Standards at the BSI website

BS 8217:2005 - Reinforced bitumen membranes for roofing. Code of practice

BS 6229:2018 - Flat roofs with continuously supported flexible waterproof coverings. Code of practice

Building Regulations Part L

Building Regulations Part B