Screed Method Statement
Scope of Works.
The purpose of this Method of Statement for screed
application is to outline the materials and labor required to undertake the
works in a safe and controlled manner, compiling with relevant legislation, standards,
and codes of practice etc.
The method statement shall be briefed to all appropriate
operatives to ensure that they are aware of the sequence of activities and any
Client/Consultant project specific requirements.
A constant monitoring and supervision duty shall be
undertaken by main contractor to ensure work activities are carried out in
accordance with the method statement. Any irregularities shall be immediately
actioned.
This method statement describes the working procedures for
screed application and all related activities. This will include surface
preparation, application, testing and post application.
General.
Prior to
works commencing, the Site Engineer shall ensure that the following activities
have been completed and signed-off by the Consultant:
- Drawing must be approved for construction by the Consultant.
- MEP Drawing & MEP Clearance must be approved.
- The concrete design mix has been approved by the consultant.
- The trial mix report has been approved by the consultant.
- The Site Engineer shall ensure that the necessary Statutory Authorities approvals have been received.
Surface Preparation.
In case that the area is nonbonding screed,
polythene sheet 1000 gauge is required to place before casting screed.
Electrical
conduits, pipes and other exposed flooring coordination’s should be cleared
from all trades prior to start the screed application.
Welded
Steel Mesh will be laid with overlap of one full square steel mesh with
distance from screed surface 400 mm and substrate surface 600 mm to avoid
surface cracks due to the distance between steel mesh and screed surface.
Clearance (MEP clearance & other clearance required)
that no interconnecting activities are balance in the work area.
Install level point 1 meter in both directions of the
surface and check the minimum, maximum and average thickness of the screed.
Surveyor will set the datum line and will transfer it to the
working area in supervision of Site Engineer and to be counter check by QA/QC
Engineer & consultant.
Ensure the proper level of the existing substrate by means
of grinding to received sound surface for the screed application. Proper
cleaning for dust and residue must be done accordingly.
Using the laser machine final check, the level of existing
substrate and mark the final level of the screed application.
Rail or screed shutter required to be in good materials and
with proper support to avoid any possible movement or being open while casting
the screed.
Provide flexible materials around the perimeter of the area
to form an expansion joint around 10 mm wide between wall, column, curbstone or
any protrusion.
Screed Application.
Screed application (pouring of screed) must be in accordance
with approved mix design for screed concrete to be used. Pouring sequence as
per approved shop drawing and in compliance of project specification.
Level the screed application to match screed line level set prior to proceed with pouring.
Ensuring it is being tampered to avoid any
developments of voids.
Mechanical power float is required to use to achieve the
finishing requirements as per approved design and specification.
Cover the finished screed with polythene sheet immediately
and cure the surface with water, keep the surface moist for at least 7 days or
curing with the used of curing compound following the manufacturers
recommendation.
Saw cut the surface as required to follow the approved saw
cutting layout at 1/3 of the depth of the screed after 24 to 48 hours but not
later than 72 hours from the time of casting.
Screed Traffic Access.
The screed being applied need to be cured to achieve the
design strength following procedure set in the project specification. The
traffic access to the area where screed is being applied must be monitor as follow:
- 48 hours for foot traffic after the pouring time.
- 14 days for light ladder or heavy foot traffic.
- 28 days for full traffic by other trades subject to resecting the load capacity of screed compressive strength.
Screed Repair Procedure (if required).
Cracks might be visible in screed, if the appearance of
cracks have been observed it will be repaired by approved materials (to be
submit for approval prior to start using in site).
Chase the cracks using chisel to V shape the crack surface
or to open the cracks using angle grinder.
Wire brush the blow dust and debris from the cracks to
ensure that the crack surface is clean properly before application of approved
repair material.
Refer to the manufacturer’s recommendation for proper
application of repair materials & curing if required.