2017 METHOD STATEMENTS AND DEMOLITION TECHNIQUES

1. Demolition Considerations/Method
Statements.

2. Considerations.
Sequence and
operations
Durations
Demolition methods
Choice of plant
Quantities Involved
Risks
Based on drawings and information/legislation
Site visit
Look for significant elements/stages of demolition
Break them down into manageable activities
Detail dependent on stage of preparation and
information available.
Relate to construction
form/constraints.
Materials handling
Hoisting and access
equipment
Scaffolding
Temporary works.
Resource availability
Sub contractors
Specialist Contractors
Plant/labour
Supervision
Think
Think
Think

4. CDM 2015 has a specific Regulation on the H&S issues for
demolition or dismantling of a structure.
• Regulation 20 Demolition or dismantling
• (1) The demolition or dismantling of a structure must be planned and
carried out in such a manner as to prevent danger or, where it is not
practicable to prevent it, to reduce danger to as low a level as is
reasonably practicable.
• (2) The arrangements for carrying out such demolition or dismantling
must be recorded in writing before the demolition or dismantling work
begins.
• Demolition works can create major site hazards and can be the cause of
death and severe injury amongst site workers and others e.g. members of
the public passing by or those working in adjacent premises.
• The person planning the demolition or dismantling project must consider
all aspects of the task so as to prevent or reduce danger to all persons who
may be affected by the works.

5. CDM 2015 Practical requirements for
managing demolition
• First, ensure that whoever is designing and implementing the demolition
or dismantling works is competent to do so.
• All but the most simple of demolition works will benefit from the
assessment of a structural engineer and/or surveyor.
• Consider what needs to be demolished, when, why and how. Consider the
environmental factors — weather conditions, wind speeds, etc. What
information has been collected regarding the structure to be demolished
— i.e. information from the Health and Safety File for the building, the
way the original building was constructed and the recommended
sequence for demolition.
• Consider the use of the building and if any persons will still be in the
vicinity when demolition takes place.

6. Legal Considerations.
• The BSI Code of Practice for Demolition BS 6187 exerts further
influence.
• If the demolition contractor does not observe the
recommendation of the Code, this may influence a court’s
decision in any legal proceedings. The Code itself does not,
however, have any statutory powers.

7. Listed buildings
• Demolition of listed buildings requires listed building consent,
and consent is normally required for all buildings in a
conservation area. Listed building consent may be given
subject to conditions, and these can be quite onerous.
• In practice, any proposal to alter a listed building may involve
at least a partial demolition, but the matter needs to be
judged on a sensible basis, since not every piece of work of
alteration and extension necessarily amounts to demolition (R
v North Hertfordshire District Council (1981) JPL 752).

8. Building Act 1984
• The local authority must be given 6 weeks written notice of an
intention to carry out a demolition.
• The local authority has powers to serve a notice regarding
demolition orders. In England (outside London) and Wales, notice
of any proposed demolition must be given to the local authority,
the occupiers of neighbouring buildings, and gas and electricity
companies.
• Exceptions are buildings smaller than 50 m3 in volume,
greenhouses, sheds etc, where the building is an agricultural
building.
• In the UK the local authority has six weeks in which to serve notice,
specifying detailed requirements about shoring, adjacent buildings,
weatherproofing, disposal of rubbish, removal of sewers and
disconnection of services, together with general safety and related
matters. A person served with a notice under the Act requiring him
to do work has a right of appeal to the magistrate’s court.

9. Demolition notice
• This notification must specify the building to
which it relates and the area of demolition.
• Notification can be provided by letter, fax or
email, however, for convenience some LA’s
will have a designed a form that you can
complete.

10. Demolition requirements
(1)
• These requirements could include:
• To shore up any building adjacent to the building to which this
notice relates.
• To weatherproof any surfaces of an adjacent building which
are exposed by the demolition.
• To repair and make good any damage to an adjacent building
caused by the demolition or by the negligent act or of any
person engaged in it.
• To remove material or rubbish resulting from the clearance
and demolition of the site.
• (*)To disconnect and seal, at such points as the Council may
reasonably require, any sewer or drain in or under the
building.

11. Demolition requirements
(2)
• To remove any such sewer or drain and seal any sewer or
drain with which the sewer or drain to be removed is
connected.
• To make good to the satisfaction of the Council the surface of
the ground disturbed by anything done under paragraph(*).
• To make arrangements with relevant statutory undertakers for
the disconnection of the supply of gas, electricity and water to
the building.
• To make such arrangements with regard to the burning of
structures or materials on site as may be reasonably required:
– if the building forms part of special premises, by the Health
& Safety Executive and the Fire Authority; and
– in any other case, by the Fire Authority.

12. Environmental Consents.

13. Environmental Consents

14. Structured approaches

18. Methods Of Demolition.
• More care and consideration is now given to the development of
demolition strategies as part of the process of construction and
redevelopment than was typical in previous times. This is a result of:
• Current emphasis on reducing construction periods to ensure economic
redevelopments;
• Increasing town centre regeneration, calling for careful demolition on
constrained and restricted sites;
• The importance of conservation, public awareness, and increasing
pressure to reuse materials.
• The aim of this part of the lecture is to:
• Set the demolition of structures in perspective as part of the construction
process;
• Consider the factors that may determine the demolition method selected:
• Outline the range of techniques available to the modem demolition
contractor.

19. Developing a demolition strategy
• Obviously each case considered for demolition
requires an appropriate strategy, depending on the
circumstances. The strategy must take into account:
• Method of construction used for the original building;
• Proximity to other buildings, structures and the
general public;
• Location;
• Cost and availability of tipping and disposal:
• Desirability and economics of reuse.

20. Building Information
• Information on buildings, in terms of ‘as built’ drawings and
structural details, is often unavailable or unreliable.
Investigative site and desk work may therefore be necessary.
• To plan the most efficient method of demolition, it is
important to have a full understanding of both the original
method of construction and the stress patterns imposed upon
it.
• Failure to do so may risk the safety of both demolition site
operatives and those in close proximity to the site.
• In extreme cases a lack of knowledge of the structure could
result in uncontrolled collapse. Buildings containing pre or
post-tensioned components require particularly careful
analysis and calculation to avoid such risks.

21. Recycling of materials and conservation
• Recycling
• An important development associated with demolition techniques is the
recycling of materials for reuse. There has always been an element of
salvage in demolition. but until recently this was confined to the reuse of
timber, tiles, bricks etc. Modern equipment makes it possible to recycle a
number of materials.
• Concrete can be crushed to provide valuable aggregates, hardcore or fill.
• The recycling of bituminous-based materials such as tarmacadam and
asphalt has also proved to be very successful and economical
• The recycling of brickwork by crushing and using the resultant material for
calcium silicate bricks is now considered economically viable.
• In the near future, buildings may be viewed as ‘reservoirs’ of materials
that will become available at some later date (see DTI demolition protocol
for further information).

22. Selecting the appropriate techniques
• Major factors to be considered include:
• Safety of personnel and public.
• Working methods.
• Legislation applicable.
• Insurance cover.

23. Preliminary aspects before site demolition work
• If demolition work is not planned at an early stage, site operatives
invariably have to devise their own means of access and methods of
working without full information as to the risks and dangers involved.
Before work starts on site, therefore, the following preparations should be
made:
• Conduct a site and building survey, with a structural bias.
• Examine drawings and details of existing construction where available.
• Prepare details and drawings from site survey activities where information
is not available.
• Find out the previous use of premises, especially with regard to flammable
substances or substances hazardous to health or safety, such as chemicals.
• Programme the sequence of demolition work.
• Deal with services.
• Prepare a Method Statement.

24. Method Statements.
• Essential element of the contractor’s
planning process is the construction
method statement. These underpin the
programme.
• Three distinct formats
– The tender method statement.
– The construction or work method statement.
– The safety method statement.

25. Method Statement Formats.

26. Construction method statements
• A construction method statement precedes
preparation of the project programme and contains
the detail necessary for construction of each element
of a building.
• They are prepared in order to explain the
contractor’s proposed working methods and
demonstrate how the durations and sequence of
work shown on the master programme will be
achieved.
• At the pre-contract stage in the project, method
statements will be prepared in detail in order to be
sure that durations are accurate and reliable.

27. Method statement presentation
• Can be written statements or in tabular form and functions as a brief for
site staff and operatives in sequencing activities and are used to indicate
resource requirements and to determine the duration of each element.
• It complements construction programming by providing detailed analysis
of each activity.
• The main uses for work method statements are:
• To calculate activity durations for the programme.
• To decide on gang compositions and thus the resourcing requirements for
individual activities.
• To plan activities in detail so that a logical construction sequence is
adopted.
• To provide an easily understood document, which can be communicated
to those who will carry out the work on site.

28. Preparation
• Preparing method statements requires discipline and
logic in that the steps needed to complete an activity
have to be thought out.
• Hand in hand with this is consideration of what plant
and labour will be used, as this is fundamental to
achieving a sensible working method and sequence.
• Temporary works and working space requirements
will also have to be considered, as will
subcontractors’ attendance requirements for
packages such as piling and structural steel erection.

29. Duration Calculation
• In order to calculate the duration of an activity, the output of
the gang has to be considered.
• Outputs used by estimators are not suitable for planning as
these relate to measured bill items where both main
quantities and smaller items are included.
• E.g. brickwork, for instance, the bills of quantities will include
an item for facing brickwork, say, and there will also be items
for laying the damp-proof course, for closing cavities and for
building in lintels.
• All these items would make calculations too complex for
planning purposes and thus ‘incidental’ items should be
reflected in an overall output for the facing brickwork quantity
alone.

30. Example
• The activity duration in days would then be
given by:
Quantity of brickwork in m2
Output of gang/hr x 8 hrs/day
• Where output is expressed in m² per hour.

31. Example 2
• Alternatively, the quantity of bricks in thousands can
be calculated and divided by the output of the gang
in bricks laid per day. This is fairly straightforward but
the difficult bit is to judge what the output should be.
This will depend on factors such as:
• The gang make up
• The type of work
• Location of the work
• The standard expected in the specification

32. Useful additions/Access/Egress

33. Site Set Up/Hoardings

34. TPO’s

35. Example 3
• The handout illustrates the plan and section of
a reinforced concrete basement to be
constructed as part of a multi storey office
development project on an open site.
• Prepare an operational method statement
from the information provided.

36. Example 3