Method Statement for installation External Insulation & Finishing System (EFIS).
INDEX.
1. PURPOSE.
2. SCOPE OF WORK.
3. METHODOLOGY.
1.0 PURPOSE
The purpose of this Method Statement is to give the outline
of each activity we are intending to
execute on site, to identify the risk associated during the installation of the
External Insulation & Finishing
system (EFIS), and to identify the
control system to ensure full compliance to the approved Shop Drawings as
well as the Contract
specifications.
2.0 SCOPE OF WORK
The scope of this method statement is to define the
procedure that will be followed for Supply and application of External Insulation
& Finishing system (EFIS).
3.0 Methodology
The area where the EIFS installation will be done shall be
inspected, marked on the drawings, the structure and agreed upon in terms of
area as well as extent of the system to be installed.
The surfaces agreed for the installation of EIFS shall be
accepted free from mortar, snorts, loose concrete, rebars and ties, tie holes,
oil, grease, friable matter, curing compounds, coatings, markings, surface
cracks, structural defects including off alignments or any other matter that
shall hamper the flawless installation of the system in any way.
Main Contractor must provide Civil & MEP clearance or
any interfacing activity clearance as well as area hand over certificate to
PFC, prior to commencement of EIFS works.
Installed scaffolding platforms are to be made available in
position to access the substrate safely and easily to facilitate the
installation of the EIFS in line with the site Safety Regulations. A clear gap
of 400 mm between scaffolding and substrate is mandatory and to be maintained
as tooling space to carry out the work. If the gap is less than this it would
affect the work as well as the quality Survey.
Prior to any installations it is mandatory to survey to
ensure planarity of the substrate. This is achieved by putting level buttons at
various points of the substrate.
Nylon string lines are fixed from top to bottom over the
level buttons to determine the planarity of the surface thereby estimating the
thickness of the insulation board required on specific areas.
3.1. SURFACE PREPARATION:
The surface should be clean, dry, and sound. The treatments recommended for the system
symptoms are given below.
SYSTEM
SYMPTOM
|
TREATMENT
|
Damp
|
Rectify
causes and allow drying out.
|
Dusty / Dirty
|
Brush down,
pressure clean and prime with approved material
|
High Porosity
(AAC Blocks)
|
Seal the
substrate by approved material
|
Efflorescence
|
Brush down
and prime with approved material
|
Mortar Lumps
|
Remove mechanically.
|
Grease,
shutter oil remains
|
Steam clean,
using detergent additives. Wash off again with water.
|
Render with
damaged areas
|
Remove loose
render; fill holes and repair the surface where required with approved
material
|
Peeling
Coatings
|
Remove old
coating, pressure clean and prime with approved material
|
NOTE: Mineral wool
EIFS insulation cannot be rasped level! – substrate level assessment is
critical mineral wool insulation EIFS systems: (unlike eps EIFS systems)
undulations in mw insulation boards cannot be rasped level at board
installation stage. As a result, correct
installation/ inspection of the levelness of the substrate wall is critical to
ensure that the finished EIFS system does not have undulations in the
finish.
For acceptable substrate
tolerance levels see EIFS manufacturer document “evaluation of substrates and
EIFS finishes/acceptable tolerance”. If maximum levelness tolerances are not
met, agreement must be made in writing with design team/main contractor &
EIFS sub-contractor on the remedy prior to EIFS start mineral wool board installation.
3.2. PRIMING OF MINERAL WOOL INSULATION BOARDS (PRIOR TO ADHESIVE FIXING).
Check the quality of board surface and if
necessary, apply the primer as per manufacture recommendation on the flat side
of the boards to consolidate the surface. (Please note that
when applying primer, the boards should be in the upright position). Allow the
primed boards to dry overnight.
3.3. ADHESIVE FIXING OF MINERAL WOOL INSULATION BOARDS:
Recommended dimension of the Mineral Wool Insulation
board: 0.6 m x 1.2 m. Mineral Wool is to
be non-combustible & manufactured in compliant with local regulations &
Euro class A1 of BS EN 13501-1 or ASTM E 136.
Level Substrate (Method 1. Notched
Trowel) Uneven Substrate up to 10mm. (Method 2. Ribbon and dab)
Used adhesive between masonry
substrate & MW (Mineral Wool insulation boards) as per material
recommendation. Allow the material to stand for about 5 minutes, remix &
use. Mix only enough material for immediate use to avoid wastage.
Following Mineral wool board
priming application, apply 1 coat of mortar adhesive to the Mineral wool board
using a 10 mm notched trowel in a downward direction at 90 º angles over entire
board and immediately fix the board against the substrate and allow to dry
overnight. DO NOT MAKE BEAD AROUND BOARD EDGE.
Mineral Wool Insulation board edges
should be kept adhesive free to prevent thermal bridging.
Fix insulation boards in staggered
pattern (running bond) and ensure all outside and inside corners are
interlocked. Offset insulation board’s joints 200 mm or more from the corners of
openings around doors, windows, or other similar conditions. Ensure that all opening corners are cut
(L-shape) from one piece of board. Insulation boards must not bridge expansion
joints in masonry or concrete substrates.
Install a movement/expansion bead if such joints present.
Fix insulation board as per
adhesive method. Ensuring boards are level (use plumb line / spirit level/
2-meter straight edge).
Back wrapping with reinforcing
fiberglass mesh and embedding mortar is recommended for all insulation boards
at system terminations (end reveals / openings) to reinforce the edges and also
prevent water ingress.
Allow board Adhesive
to dry for 24 hours.
Avoid gaps between Mineral wool
boards (Do not fill gaps with base coat) In event of gaps< 5 mm -fill with
strips of cut Mineral wool and trim level with MW board surface.
Co-ordinate for the approval of
Mineral Wool board installation levels prior to mechanical fixing.
3.4. MECHANICAL FASTENERS/DOWELS INSTALLATION OF MINERAL WOOL BOARDS.
EIFS system is
designed as a mechanical fixed with supplementary adhesive.
EIFS Mechanical Fasteners
are fixed directly through the un-coated board after a minimum of 24 hours – see
Figure A for location of fasteners per board (5 numbers per board) See Figures
B, C for additional fasteners around window openings and corners.
EIFS Mechanical
Fasteners (PP dowel with PP - PA nail)
should penetrate a
minimum of 4 cm
into concrete, solid concrete, and hollow concrete block substrates. Mechanical
fasteners should penetrate a minimum of 7 cm into the AAC / ALC substrates to
secure anchorage.
Ensure dowel heads
are level with the insulation boards to prevent bumps in the final finish.
Four EIFS Fasteners
at the corners & one fastener in the center of each board (for board of size
0.6 m x 1.2 m) and additional fasteners around windows/doors/openings and corners
as indicated in figure B, C.
3.5. CORNER PROFILES & DIAGONAL STRESS PATCH MESH.
For corners, window lintels and
column edges; EIFS Aluminum corner beads or alternatively
EIFS Plastic corner beads with fiberglass wing
mesh (10 cm x 10 cm) are used at all
corners/opening to protect edges
from impact and to achieve consistently straight edges. Fix windows reveal beads as required.
Fix diagonal Stress patch mesh on all
corners as indicated in Fig D below and overlap with corner bead mesh
to prevent cracks at corners.
3.6. CONTACT AREAS - BASE-COAT APPLICATION & FIBERGLASS MESH:
CONTACT AREAS - For areas up to 2 m
height from ground level.
Apply 1 coat of a solution on the entire surface of the fixed mineral
wool boards.
Apply 1st coat of base-coat by
trowel to an approximate thickness of 2 mm and immediately embed the 160 g/m2
fiber glass mesh into surface by troweling from center out to avoid any
wrinkles. Overlap all fiber glass mesh edges
by 10 cm. Level with a 60 cm scraper
without sprinkling water on the surface.
Allow the first layer of adhesive overnight
drying time before applying the second layer.
Following drying of 1st coat
lightly dampen the dried first coat of base-coat with water using a crop
sprayer; then apply the second layer.
Apply 2nd coat of base-coat by
trowel to an approximate thickness of 2 mm and immediately embed the 160 g/m2
fiber glass mesh into the surface by troweling from the center out to avoid any
wrinkles. Overlap all fiber glass mesh
edges by 10 cm. Level with a 60 cm scraper without sprinkling water on the
surface. Allow the second layer 12 – 16
hours drying time before applying the third layer.
Following drying of 2nd coat,
lightly dampen the dried second coat of base-coat with water using a crop
sprayer. Apply 3rd coat of base-coat by
trowel at 1 mm to 1.5 mm thickness. Ensure the full cover of the mesh and level
off with a 60 cm scraper without sprinkling water on the surface.
3.7. NON-CONTACT AREAS - BASE-COAT APPLICATION & FIBERGLASS MESH
NON-CONTACT AREAS –
Areas 2 m height above ground level (and above) & areas not accessible
to public or as
per project building requirements.
Apply 1 coat of
solution on the entire surface of the fixed mineral wool boards prior to
application base-coat.
Apply 1st coat of base-coat by trowel to an approximate thickness of 2 mm and
immediately embed
the 160 g/m2 fiber glass mesh into the surface by troweling from the center out
to avoid any wrinkles. Overlap all fiber
glass mesh edges by 10 cm. Level with a 60 cm scraper without sprinkling water on
the surface.
Allow the first
layer of base-coat overnight drying time before applying the second layer.
Following drying
of 1st coat lightly dampen the dried first coat of base-coat with
water using a crop
sprayer; then apply the second layer.
Following drying
of 2nd coat, lightly dampen the first coat of base-coat with water using a crop
sprayer. Apply 2nd & final coat of base-coat by trowel at 1 mm to 2 mm thickness.
Ensure the full cover of the mesh and level off with a 60 cm scraper
without sprinkling water on the surface.
Total thickness should be 3 mm-4 mm.
Co-ordinate for
the approval of base-coat levels prior to solution
application.
Note. It is important to
prevent water ingress behind the EIFS. Therefore, special care should be taken
to treat all gaps between system & walls especially above window & door
heads, beneath window & door sills, sides of windows & doors, at roof
/wall intersections, abutments of lower walls with higher walls, projecting
features & base of the walls etc. Fill in the gaps with low expansion PU
foam, cut back and seal with appropriate exterior grade fire rated sealant. A
better option would be to fix suitable aluminum flashing over these gaps to
direct water to the exterior. The top of the parapet wall should be covered
with suitable aluminum or GRC coping. Gaps around flashing should be sealed
with FIRE RATED SEALANT.
3.8. DECORATIVE FINISH:
Rollers apply 1
coat of primer and allow to dry.
Apply 1 coat of TEXTURE
COATING (as per approved texture & color) to
a thickness of 1.5 –
2 mm and allow to dry.
Note:
Application should
not be done at very low or high temperatures (< 5 c or ≥40 c) and/or in very windy conditions.
Plans work accordingly.
Do not apply if rain
is expected over the next 24 hours.