Below is a precise scaffolding method statement, purpose of this document is to provide instruction for the installation, erection and use of scaffolding or formworks for multiple purposes applicable for any kind and size of project.
All scaffolds in excess of 10m in height need to be specially designed, as do sheeted scaffolds exceeding 5m in height or any scaffolds exposed to very high winds.
In these cases the scaffolding should comply with the procedures of temporary works.
All scaffolds should only be erected, altered or dismantled by competent and experienced persons who should be in possession of a valid scaffolding certificate.
Hazard Identification and Risk Assessment
Most people in the construction industry have to work upon scaffolding from time to time.
Approximately 60% of all accidents are caused by falls of persons or materials.
A safe working platform therefore should come high on the list of priorities when identifying hazards and implementing risk assessments.
The key to safety in scaffolding comes from good preparation and planning.
Before the erection of any scaffolding the following points should be carefully considered:
i. What is the scaffold for
ii. Exactly where is it to be erected
iii. What materials are to be used
iv. Can safe access be provided for erection and use
v. How many working platforms are required
vi. What loadings will be imposed
vii. Are ground conditions suitable
viii. Are there any overhead dangers
ix. How will the scaffold be tied
x. Are the scaffold erectors trained, competent and under suitable supervision
xi. Has the scaffold company adequate resources to meet the requirements of the contract (men, materials and experience)
Risk Checklist for Scaffolding Installation
i. Falls of persons and materials.
ii. Collapse of structure.
iii. Contact with overhead electricity services.
iv. Scaffold erection over underground services.
v. Erection by untrained, incompetent persons.
vi. Obstructed access or unsafe access to occupied scaffolded properties.
vii. Undermining of scaffold.
Control Measures
General Scaffolding requirements
A safe place of work, with safe access and egress should be provided and properly maintained.
Scaffolding should only be erected, altered and dismantled under supervision of a competent person and by people with adequate experience and holding a scaffolding certificate or trainer permit.
Scaffolding should be constructed of sound, materials in good condition and properly stored when not in use.
No defective materials or parts used and no excessive wear or corrosion.
Before any scaffold is used, and every 7 days thereafter, the scaffold must be inspected by a competent person and an accurate entry made in the register Report of Results of Weekly Examinations (site records). A “Scaff-Tag‟ must be signed and displayed at all access points of the scaffold.
Where a scaffold is erected by an outside contractor, a representative from that company should sign the register to the effect that the scaffold is erected in compliance with all statutory requirements, or provide a handover certificate.
No scaffolding should be left partly erected or dismantled, unless adequate notices are displayed and access blocked.
No metal scaffold should be erected in close proximity to overhead power lines.
Mandatory safety harness signs to be displayed at entrance to scaffold and all workers to wear and secure harnesses on working platforms.
Scaffolding Materials
- Tubes and fittings are to comply with relevant standards, ends cut clean and square, free from bends, distortion, corrosion, splits or surface flaws.
- Fittings free from worn threads or damaged bolts and excess oil which may reduce friction grip.
- Boards to comply with relevant standards; not to be warped, twisted, split or badly worn, or painted to conceal defects.
Formwork / Scaffolding Foundation Requirements
Foundations for formworks should be of adequate strength to support and distribute the load.
On hard surfaces, such as steel and concrete of sufficient strength and thickness, standards may be placed on the surface with the inclusion of a metal base plate.
On all other surfaces, the load should be spread by using base plates and sole plates.
The soil or ground beneath the sole plates should be level and properly compacted.
A sole plate used on hard ground, beneath any one standard, should be at least 1000cms with a minimum dimension of 219mm.
If a timber sole plate is used it should not be less than 35mm thick.
On soft or disturbed ground, the sole plate area should not be less than 1700cms for an individual sole plate and 3400cms when combined under two standards.
At all times a metal base plate should be used between sole plate and standard.
On sloping ground steps should be cut into the slope to accommodate sole boards and base plates.
If the slope exceeds 1:10, an engineer should check that the ground has sufficient stability.
Standards Installation Requirements
These will be placed vertically to within +/- 20mm in any 2m in length, to a maximum total deviation of 50mm.
Joint pins may be used to connect standards in line when the joint is in compression – where the joint is in tension then sleeve couplers should be used.
Joints in standards should be staggered such that adjacent standards are not jointed in the same lift.
Of the 4 standards at the corner of the scaffold only 3 may be joined in the same lift, except in the lower 6.5m of scaffold where an extended base lift is necessary.
In such cases all 4 standards may be joined in the same bay, provided one of the joints is lapped with tube and parallel couplers.
Scaffolding Ledgers Installation
Ledgers are fixed to standards with right angle couplers.
They would normally be horizontal but may follow the slope of ground at the “foot” lift.
In this case the ledgers would be fixed to the transoms which are attached to the standards with right angle couplers.
Joints in ledgers should also be staggered, i.e. joints in adjacent ledgers should not occur in the same bay.
These joints should be made with sleeve couplers and not be more than one third distance away from a standard.
Joints in ledgers on the same lift and in adjacent lifts should not occur in the same bay unless there is unjointed guardrail (not to be removed) when joints in the ledgers above and below can be in the same bay.
Spacing of ledgers (lift heights) will be:
i. independent tied scaffolds – 2.0m
ii. putlog scaffolds – 1.35m
e) First lifts of up to 2.7m are acceptable where access underneath the scaffold is required, this will result in reduced loading capacity.
Installation of Scaffold Transoms
Transoms, keeping the inner and outer rows of standards evenly apart are set on top of ledgers at right angles to them and to the building.
Horizontal distance between transoms at working platform level is determined by the thickness of the boards to be used, e.g. for 38mm thick boards every 1.5m and so spaced to ensure no board overhangs by more than 150mm or less than 50mm.
Transoms are secured to ledgers with either right angle or putlog couplers unless braces are secured to them, in which case only right angle couplers are acceptable.
On boarded lifts, transoms will be spaced to ensure adequate supporting of the scaffold boards (See Section 6.3.11) – overlap 50mm over the transom.
On non-boarded lifts and transoms should be secured at not more than 300mm from each standard or pair of standards.
Scaffolding Couplers Installation
These components are classified into two categories – load bearing and non-load bearing.
Load bearing couplers or components are:
i. Right angle couplers
ii. Swivel couplers
iii. 5 KN brace couplers
iv. Adjustable fork heads
v. Adjustable base plate jack
Non-load bearing couplers or components are:
- Expanding joint pins
- Toe board clips
Bracing Requirements
No scaffold can remain stable or safe unless properly braced. Bracing should remain in position at all times to ensure this stability.
There are two main types of bracing, as follows:
Façade Bracing
i. Fixed to the longer face of the scaffold normally parallel to the face of the structure and is fitted to the outside row of standards.
ii. It can either run across the face of the scaffold to its full height at an angle of 45 degree or run in zig-zag fashion to its full height.
iii. Bracing should be provided at least every 3.0m along the scaffold.
iv. Bracing will be fixed to extended transoms with right angle couplers or to standards with swivel couplers.
Where braces are fastened to transoms, the transoms should be fixed with right angle couplers, (load bearing) to the scaffold.
Brace couplers may be used as an alternative.
Joints in any continuous sloping tube can made in one of three ways:
– Overlapping the two lengths of tube by at least 300mm and fixing with two parallel couplers.
– A joint pin with a splice tube fixed with parallel couplers either side of the joint.
– A sleeve coupler.
Ledger Bracing
i. Fixed to join inner and outer alternate pairs of standards, fixing is by using right angle or brace couplers connected to the ledger or with swivel couplers to standards.
ii. When bay length is 1.5m or less, the bracing may be fixed to every third pair of standards.
iii. On boarded lifts the brace would be fixed under the outside ledger to the inside ledger of the lift below to avoid the toe board.
iv. Bracing may be fixed from the inside ledger to the guardrail level of the below provided that every pair of standards are braced.
v. If access is required under the scaffold the bottom lift ledger bracing may be omitted, in such cases the loading capacity of the scaffold is reduced, in some cases by as much as 50%.
Types of Scaffold Ties
a) It is essential that all scaffolds are properly tied into the building or structure at intervals to ensure the safety and stability of the scaffold.
Types of tie include:
i. Through Tie: A tie assembly through a window or other opening in a wall.
ii. Reveal Tie: The assembly of a reveal tube with wedges or screwed fittings and pads, fixed between opposing faces of an opening in a wall together with the tie tube. Relies solely on friction, therefore safe working capacity is reduced. Ideally they should not be more than 50% of total number of ties.
iii. Box Tie
– The assembly of tubes and couplers, usually around columns or other elements of the building.
– The above types of tie are all of the moveable variety, this means they can be removed, one at a time systematically, then replaced after the task necessitating the removal is complete.
No tie may be removed without the agreement of the competent person.
The following are non-removable types of tie:
Cast-in and Drilled Anchorages
Provided by casting in, or fixing a threaded anchor sleeve into the structure itself.
The attachment of the scaffold to the anchor sleeve is either by a ring bolt or tied and secured by wire lashing.
These types should be used in accordance with manufacturer’s recommendations.
The capacity of the anchorage into the structure must be established by test, 50% need to be pull tested.
Tie Frequency Table
a) The spacing of lines of ties should not exceed 8.5m horizontally or vertically.
Ties should be reasonably evenly distributed over the scaffold at the following minimum frequency based on ties of 6.25kn capacity.
Type of Ties Unsheeted Scaffold Sheeted Scaffold
Movable Ties 32m2 12.5m2
Non-Movable Ties 40m2 16m2
b) When dealing with sheeted scaffold above 5m high and on all other scaffold greater than 10m high, the scaffolding should comply with temporary works procedures.
c) Reveal ties are not to be used on sheeted scaffolds.
d) Ties should be secured to both inside and outside standards and ledgers to be fixed within 300mm of a braced standard.
Returns, Buttresses and Rakers
May be used as an alternative to a tie and are generally considered to provide attachment for a 3m length either side of the buttress or raker.
A return is considered adequate for a 3m length measured from the outside corner.
Rakers should be set at an angle not more than 2 vertical to 1 horizontal and fixed at its base to prevent sinking or slipping.
Tubes more than 2.7m in length should be fitted with a brace, tied back to the scaffold to prevent distorting under load.
Standard Requirements for Working Platforms
In all circumstances where it is possible to provide platform widths as listed below then the stated dimensions should be maintained.
If for reasons of limited space it is not possible to provide such widths, then that platform should be as wide as the space permits.
Minimum widths of platforms should be as follows:
i. At least 3 boards 600mm – for persons only and not for the deposit of materials.
ii. At least 4 boards 800mm – for persons and deposit of material leaving a clear passage of at least 430mm.
iii. At least 5 boards 1.05m – if used to support any higher platform.
iv. At least 6 boards 1.30m – if used by persons to dress or shape stone
v. At least 7 boards 1.50m – if used by persons to dress or shape stone, and to support their trestle platforms.
When work has to be done at the end of a wall or other structure, then the working platform should extend at least 600mm beyond this point.
The working platform should be placed as close to the face of the structure as possible.
All scaffold platforms should be closely boarded.
Scaffold boards should be free of large splits and knots and should be banded at both ends and not cut in any way.
No board should overhang its last support by more than 4 times its thickness, but should have a minimum overhang of 50mm.
Any group of boards across the width of a scaffold should be of the same length and thickness.
The spacing of board supports (transoms) should be as follows:
- 38mm thick boards – 1.5m maximum centres
- 50mm thick boards – 2.6m maximum centres
- 63mm thick boards – 3.25m maximum centres
Scaffold boards should normally have at least three supports.
38mm thick boards less than 2.13m long should not be used unless they are fixed down to prevent tipping.
Boards less than 1.8m long may be supported on two transoms, but should be fixed down at both ends.
Scaffold boards should be laid so that there is no trip hazard created.
Where any possibility of displacement exists from high winds, boards should be fastened down.
Where platforms become slippery due to frost, snow, mud etc., the boards should either be cleared or turned over.
Every scaffold platform from which a person can fall should be fitted with guardrails and toe boards.
Where any other risk of injury exists i.e. falls onto starter bars, such platforms should be similarly protected.
Guardrails and toe boards are required at the outsides and ends of all working platforms, and on the insides, if gaps exceeding 300mm have been left for working at the face of a building or structure.
Toe boards and guardrails should be fitted on the inside of standards to prevent outward movement.
Toe boards should rise at least 150mm above the working platform.
Guardrails should be not less than 950mm, nor more than 1.15m above the working platform.
Middle guardrail must be 470mm from the working platform.
Where a fall risk position exists or is identified, safety harnesses must be utilized and training must be provided.
Loadings on Scaffolds
Scaffolds should not be overloaded.
Where materials have to be stacked higher than toe board height, mesh guarding panels or similar substantial protection should be fitted to the scaffold.
Materials should not be stored on a platform unless it is needed for work within a reasonable time.
When scaffolds are loaded out, materials should be deposited with a minimum of shock loading.
Scaffold Classification
Scaffolds are classified by type according to their purpose for use.
Each scaffold will have set maximum loadings which in turn will determine the maximum bay centres as follows:
Birdcage Scaffolds
Having multiple rows of standards.
A birdcage scaffold will normally only have one boarded lift.
Standard spacing will be no greater than 2.5m in any direction.
Lift heights should not exceed 2m with the exception of the first lift, which for access purposes may be to 2.5m.
Each line of standards should be braced to the full length of the scaffold at a frequency of one brace for every six standards. This can either be diagonal or zig-zag bracing for scaffolding up to 6m in height. For scaffolding greater than 6m in height use diagonal only.
On single lift birdcage scaffolds foot ties should be fixed to alternate bays to form boxes and ledger bracing fixed in two directions or alternate boxes.
Joints in all horizontal tubes in the working lifts should be made with sleeve couplers.
The working lift should be tied at intervals of 8m around the perimeter.
In circumstances where the height of the scaffold is greater than the lesser base dimension, the scaffold should be tied at intervals of at least 1 tie per 40m2 of vertical face.
Scaffold Towers
These should be erected in accordance with “General Scaffolding Requirements”, and the appropriate standard relating to prefabricated mobile scaffold towers.
Lightweight Aluminum Formwork Scaffold Systems
i. Before the system is used a method statement covering erection, striking and relocation should be prepared for approval by the Project.
ii. Site management should satisfy themselves that all personnel involved in the use of the systems are competent and are fully conversant with the method statement.
iii. Regular checks should be carried out by site management to ensure the method statement is being followed.
iv. Due to its light weight the system may be unstable and should therefore be tied to prevent moving or overturning.
v. Access and egress should only be by ladders of the correct length. Personnel should not climb up the structure.
vi. Components should be stored so that damage does not occur, and should also be maintained and checked on a regular basis.
vii. When the system is being used as normal formwork and not in its “table form” style, then a temporary working platform should be provided when fixing and striking the primary and secondary cross beams. All beams should be connected using the appropriate clips.
viii. Any tableform units should be suitably anchored before anyone is allowed to work on them, particularly cantilevered ones.
ix. The method of providing edge protection should be checked for suitability. The guardrail may be at an incorrect height when the slab is poured and the base fixing may be inadequate to support a longer standard.
x. Where a fall risk position exists or is identified, safety harnesses must be utilized and training provided.
Truss-out Scaffold
A truss-out scaffold is an independent tied scaffold, which projects from the face of a building or structure.
The supporting structure is known as truss-out.
These scaffolds are generally used where it is impractical, or inadvisable to build up from ground level, for example work on upper storeys in a tall building on a busy street.
They are entirely dependent upon the building for support therefore:
- A full method statement containing the design details should be compiled.
- The scaffold should be specially designed with copies of the design details kept on site.
- Should only be erected by trained and experienced scaffolders.
- The building or structure should be examined to ensure that it is capable of taking any loads or stresses.
- Only steel tubes and fittings should be used and these should be specifically checked before use.
Cantilever Scaffold Installation
A cantilever scaffold is an independent tied scaffold erected on beams cantilevering out from a building.
The following points should be complied with when these scaffolds are to be used:
- Scaffold should be specially designed, with copies of the design details kept on site.
- Strength of the structure should be checked to ensure that the loads applied by the scaffold can be safely resisted.
- Only trained and experienced scaffolders should be allowed to erect this type of scaffold.
- A full method statement, containing the design details should be complied.
Scaffolding Safety Checklist
General Tube and Fitting Scaffold
a) Have ground conditions or structure on which scaffold will be or has been erected, been checked for adequacy?
b) Has a hand over certificate been received or the register signed at handover?
c) Has a competent person been nominated to inspect the scaffold?
d) Is all scaffold erection, alteration carried out by trained persons?
e) If the scaffold is a designed type, are the approved drawings held on site?
f) Is the scaffolding being used within its load bearing capacity?
g) If the scaffold overlooks a public area, has public safety been considered?
h) If applicable have licenses been obtained from local authorities (pavement closures)?
i) Has any „incomplete scaffold‟ been fitted with the appropriate sign?
j) Are all working platforms and access ways fitted with double guardrails and toe boards?
k) Are all ladders lashed “both styles” ?
l) Have all standards been supported on adequate base and sole plates?
m) Are all scaffold boards in good condition adequately supported and correctly laid?
n) Have correct couplers been used throughout the scaffold?
o) Is scaffold adequately tied or supported?
p) Are joints in standards and ledgers staggered throughout the scaffold?
q) Are joint pins and or sleeves being used to the correct specification and in the relevant location?
r) Is all relevant bracing fitted?
s) If materials are stacked on scaffold are they well distributed?
t) Is access along work platform adequate?
u) If applicable have adequate brick guards been fitted?
v) Are site records being maintained in the correct manner?
w) If the scaffold is sheeted, has it been erected and tied for the increased wind loadings imposed?
Special Scaffolds (Cantilever – Truss-out)
a) Have the workforce been made aware of SWL and any other limitations?
b) Is a method statement available; and does it include any design specification?
c) Has consideration been given and are written records available to show „integrity checks‟ of supporting building/structures?
d) Have checks been made to ascertain level of experience of scaffolders?
e) Are all scaffold components in good condition, well maintained, being used correctly?
Relevant Records
Weekly Examination Reports
Scaffolder Certificates