Technical Data Sheet
High Performance polyurethane joint sealant
Description Sikaflex-PRO is a one component thixotropic polyurethane based joint
sealant. It cures under the influence of atmospheric moisture to form an
elastomeric material with adhesive properties in some cases without the
need for priming of the substrate.
Sikaflex-PRO is supplied throughout the world by Sika and conforms to the
most stringent sealant standards for example:
???? US Federal Specification TT-S-00230C Type II Class A.
???? BS4254: For one part polyurethane based sealants for the building
???? JIS A 5758: For one part polyurethane based sealants for the
Uses As an elastic joint sealant for:
???? Expansion joints in buildings and civil structures above and below ground.
???? Construction joints.
???? Joints in precast concrete elements.
???? External walling and cladding joints.
???? Infill panel joints.
???? Curtain walling.
???? Sanitary installations.
???? Sealing around window and door frames.
???? Flexible draught proofing.
???? Sealing penetrations in walls or floors for ducts piping etc.
???? Retaining walls.
???? Sealing joints in water retaining structures (water reservoirs)
Advantages ???? New Sikaflex-PRO will bond well to well cleaned Sikaflex-PRO.
???? Excellent adhesion on all cement based materials brick ceramics
polyurethane epoxy most polyesters most metals and most timbers.
???? High durability.
???? Good weathering resistance.
???? Non-sag on vertical and soffit joints up to 30 mm width.
???? Short skinning time.
???? Short cut off string even after storage.
???? Ready for immediate use no mixing saves time.
???? No potential mixing errors or wastage due to mixed quantities being
greater than required.
???? Can be painted over with many water solvent and rubber based paints
(preliminary tests recommended).
???? Approved for use in potable water (AS4020:2005).
???? Resistant to bacterial attack.
Instructions for Use
Clean sound dry and free of oil grease and surface contaminants such as
form release agents curing membranes and hydrophobic water repellents.
Thoroughly remove all loose particles and dust.
Masonry/Brick/Concrete: Any loose particles or laitance should be removed
with a rotary mechanical wire brush followed by blowing out with oil free
compressed air. Use Sika cementitious or epoxy mortars for making good
spalled or damaged joints.
Metals: Surfaces must be free of rust scale or oxide films and should be
degreased using Sika Colma Cleaner Acetone or M.E.K.
Priming (Refer to Primer Selection Guide for detailed information. This is a separate
Application Minimum application temperature 5°C. For easier use we recommend the
material is stored between 10°C and 30°C prior to use. Sikaflex-PRO is
available in 310 ml cartridges or 600 ml unipac. Cartridge: break the inner
seal at nozzle end affix nozzle and cut to accommodate the desired joint size.
Unipac: slide unipac into the special applicator gun then either nick the
unipac wrapper at the extrusion end or cut off the very end of the sausage if it
contains partially cured lumpy Sikaflex. Fit the gun with a suitable nozzle that
has been cut to deliver the right bead size. All primer on joint sides which is
generally applied after backer rods or release tapes are in place (refer joint
design section) must have not exceeded its open time and it must be
thoroughly dry and not just skinned over; otherwise in conditions of rising
temperature trapped solvent can blow bubbles in the uncured sealant.
Porous substrates such as poorly compacted or cracked concrete must have
their porous bond area surfaces thoroughly sealed to avoid the possibility of
air bubbles being blown into the uncured sealant if the substrate temperature
rises. Extrude the Sikaflex-PRO into the joint ensuring that no air is trapped
in the joint. Wide joints will require more than one pass of the application gun
to make sure that Sikaflex-PRO is in full contact with the sides and bottom of
the joint. Tooling-off the sealant will assist by forcing the sealant into the joint
against its sides and back up material; this will also break any air bubbles
and expose any air pockets. Final tooling of the joint surface can be done
effectively with a spatula dipped in a 20% solution of washing up detergent in
water (test to ensure it does not discolour the cured Sikaflex-PRO) or a
profiled piece of raw potato. When tooling off with detergent solution ensure
no solution is allowed to get onto adjacent joint sides/bonding areas before
the sealant has reached the final tooling stage in those locations. When
masking sides of joints for neatness remove tape before the sealant cures.
Always allow sufficient surface exposed to moisture. In conditions of low
atmospheric humidity say less than 45% R.H. at 20°C or <60% R.H. at 10°C
when early joint movement is anticipated (eg. The joint has been sealed in the
late afternoon sun and at sunset a rapid temperature drop is expected
Canberra or Alice Springs in winter) it is advisable to spray the surface of the
tooled Sikaflex with a fine mist of water to promote early skinning. Seal joints
in walls facing west in the morning.
Cleaning Use Sika Colma Cleaner to remove uncured sealant from tools after first
removing the bulk of the Sikaflex material with a scraper followed by a rag or
paper tissue. Sikaflex Hand Cleaner will remove fresh and partially cured
Sikaflex from the skin. Hardened material can only be removed mechanically.
Joint Design Permissible change in joint width at ambient temperatures:
above 0°C is ±30% of average joint width at the time of sealing
below 0°C is a total of ±20% of average joint width at the time of sealing
admissible total shear movement is 20% of joint width at time of sealing
For the successful sealing of joints with Sikaflex-PRO it is essential that the
following guidelines on joint configuration are observed:
General use: for joints up to 12 mm wide width to depth ratio = 1:1
for joints over 12 mm wide width to depth ratio = 2:1
(minimum joint depth 8mm: maximum joint width 35mm).
An approximate rule of thumb for joints in pre-cast concrete
Joint interval (metres) up to 2.0 2.0-3.5 3.5-5.0 5.0-6.5 6.5-8.0
Joint width (mm) 10 15 20 25 30
To ensure that the correct width to depth ratio is achieved and to provide a firm
backing against which the sealant can be tooled off and also to prevent the
sealant from adhering to the bottom of the joint the space under the Sikaflex-
PRO must be filled with a tight fitting non-rotting non-absorbent backing
material eg. fibreboard combined with a bond breaking tape (eg. polypropylene
or PVC) or alternatively an open cell polyurethane or closed cell polyethylene
backer rod supplied by Sika. Open cell PU backer rod has the advantages of
allowing moisture access to the front and back of the joint simultaneously
facilitating faster curing. Also open cell PU backer rod is much more
compressible than closed cell PE foam thus one diameter rod can be used in a
much wider range of joint widths. Closed cell PE backer rod can cause
bubbling in uncured sealant in rising temperature conditions if its outer skin in
punctured. It is essential that oil or tar impregnated backing materials are not
Technical Data (Typical)
Colours White Off White Sandstone Beige Pale Brown Brick Red Redwood Grey
Dark Amber Black Dark Grey (special colours on request in batch quantities)
Density 1.25 to 1.3 kg/litre depending on colour
Basis Moisture curing polyurethane prepolymer
Priming Refer separate Primer Selection Guide for more details
Application temperature 5oC to 40oC
Service temperature -30°C to 70°C (maximum +40°C in water and temporarily +50°C)
Shelf life Minimum 12 months stored dry below 30°C unopened in original containers
Shore A hardness 23 to 27 after 28 days (at 23°C 50% R.H.)
(JIS A 5758 1992)
(JIS A 5758 1992)
>0.2 MPa @ 50% elongation @ +23°C
Tensile strength at break
(JIS A 5758 1992)
Elongation at break >500%
expansion and contraction
Refer Joint Design section
(at 23°C 50% R.H.)
2 to 4 hours
(at 23°C 50% R.H.)
2 mm in first 24 hours
(rough guide only)
Dilute mineral acids
Dilute mineral alkalis
Low to Very Low
Consumption Sika Primer 1 15 ) About 4-5m² per litre of primer.
Sika Primer 3N ) 250 ml can of primer will normally be sufficient
Sika Primer 215 ) for about 35-40 running metres of
Sika Primer 35 ) 12.5 mm (deep joint).
Sika Adhesive Cleaner 1: approx. 5-8 m²/litre
Sikaflex Estimating Chart
Quantities: a guide to Sikaflex-PRO quantities (for fillet work multiply metre
runs per cartridge or unipac by two).
Joint size in mm Litre Sikaflex-PRO
per metre run
Metre run per
Metre run per
unipac (600 ml)
5 x 5 0.025 12.4 24
5 x 10 0.050 6.2 12
5 x 15 0.075 4.2 8.0
10 x 10 0.100 3.1 6.0
10 x 15 0.150 2.0 4.0
10 x 20 0.200 1.55 3.0
10 x 25 0.250 1.24 2.4
15 x 10 0.150 2.06 3.9
15 x 15 0.225 1.35 2.7
15 x 20 0.300 1.04 2.0
15 x 25 0.375 0.82 1.6
15 x 30 0.450 0.69 1.3
15 x 40 0.600 0.51 1.0
20 x 10 0.200 1.55 3.0
20 x 15 0.050 1.04 2.0
20 x 20 0.400 0.78 1.5
25 x 12.5 0.310 1.00 2.0
25 x 15 0.380 0.81 1.6
25 x 20 0.500 0.62 1.2
25 x 25 0.630 0.50 0.9
30 x 15 0.450 0.69 1.3
30 x 20 0.600 0.51 1.0
30 x 25 0.750 0.42 0.8
40 x 20 0.800 0.39 0.8
40 x 25 1.000 0.31 0.6
40 x 30 1.200 0.26 0.5
Packaging 310 ml cartridge per carton of 12
600 ml unipac per carton of 20
Sika Primers are supplied in 250 ml cans (Flammable)
Sika Adhesive Cleaner 1 is supplied in 250 ml and 1 litre cans (Flammable)
Sika Colma Cleaner is supplied in 1 litre and 20 litre cans (Flammable)
Important Notes Sikaflex-PRO is best stored at temperatures between 10°C and 25°C in dry
areas. The storage temperature should not exceed 30°C for extended
For best results use opened cartridge or sausage the same day otherwise
the Sikaflex-PRO in the nozzle will cure and have to be removed.
When applying sealant avoid air entrapment.
Joint movement must not exceed ±30% (above 0°C) of the width of the
joint at the time it is sealed.
Minimum joint width for caulking around window frames is 10mm.
White colour material yellows with age.
In some bathroom and kitchen environments Sikaflex-PRO can be stained
by interaction with other components used in the structure and finishes.
Ceramic tile adhesives containing rubber from old car tyres could be the
Joints in low humidity environments should be sprayed with a mist of water
as soon as tooling off is complete to accelerate the curing process and
minimise the risk of early movement cracks.
For specific chemical resistance please contact our Technical Service
If there is no history of a particular coating/paint being applied over cured
Sikaflex-PRO for a period of 6 months or more an overpaintability test
should be made to determine:
i) that the paint dries properly within the expected time frame.
ii) that if the paint film dries satisfactorily it is not subsequently
softenend and/or stained where it comes into contact with the
Sikaflex-PRO when exposed to the heat of the sun.
iii) That the adhesion of the paint/coating is satisfactory to the
Conduct a simple test overpaint a cured sample of Sikaflex-PRO allow the
normal drying time for the coating to elapse and then expose it to a
temperature of 80°C continuously for seven days. Sikas technical
department can conduct this testing.
Do not paint Sikaflex-PRO with Sikagard-680S it will not dry
Do not use Sikaflex-PRO to seal joints in chlorinated swimming pools or
spa pools because occasional over dosing with chlorine etc. can eventually
cause the Sikaflex-PRO surface to become sticky.
Where possible backer rod should be placed in a joint before it is primed.
Do not twist or puncture closed cell polyethylene backer rod during
installation this can lead to out gassing. The gas from the backer rod
blows bubbles into freshly applied Sikaflex-PRO during conditions of rising
Open cell backer rod allows moist air access to the bottom of the joint so
that the Sikaflex-PRO can cure simultaneously from the front and back of
Sikaflex-PRO should be used with care in resealing joints that were
previously filled with silicone sealant. Consult out Technical Department.
Not to be used in glazing applications where the Sikaflex to glass bond is
exposed to direct or indirect sunlight or UV radiation.
Handling Precautions Sika sealants are generally harmless provided that certain precautions
normally taken when handling chemicals are observed. The uncured
materials must not for instance be allowed to come into contact with
foodstuffs or food utensils and measures should also be taken to prevent the
uncured materials from coming into contact with the skin since people with
particularly sensitive skin may be affected. The use of protective clothing
goggles barrier creams and rubber gloves is recommended. The skin should
be thoroughly cleansed at the end of each working period either by washing
with soap and warm water or by using a resin removing cream the use of
powerful solvents is to be avoided. Disposable paper towels not cloth towels
should be used to dry the skin. Adequate ventilation of the working area is
recommended. In case of accidental eye or mouth contact flush with water.
Consult a doctor immediately.
Important Notification The information and in particular the recommendations relating to the
application and end-use of Sikas products are given in good faith based on
Sikas current knowledge and experience of the products when properly
stored handled and applied under normal conditions. In practice the
differences in materials substrates and actual site conditions are such that no
warranty in respect of merchantability or of fitness for a particular purpose
nor any liability arising out of any legal relationship whatsoever can be
inferred either from this information or from any written re
from any other advice offered. The proprietary rights of third parties must be
observed. All orders are accepted subject of our terms and conditions of
sale. Users should always refer to the most recent issue of the Australian
version of the Technical Data Sheet for the product concerned copies of
which will be supplied on request.
PLEASE CONSULT OUR TECHNICAL DEPARTMENT FOR FURTHER