Ardex WPM 405 (Sheltercrete Additive) High Performance
Polymer Additive for Cement and Concrete Mixes
ARDEX WPM 405 (Sheltercrete Additive) is an SBR,
multipurpose, concentrated, liquid polymer additive which greatly improves the
bond strength, flexibility and workability of sand/cement mortars and screeds.
Being water resistant, ARDEX WPM 405 mixed with cement can be used as a temporary
waterproofing sealer. When used as an admix for mortars and screeds ARDEX WPM
405 can be applied to damp surfaces (not wet) and can be painted over.
Features and benefits
Water resistant: used as a temporary waterproofing sealer
on rooftops when mixed with cement.
High strength: ideal for use in patching mortars as it
can be feathered out with minimal cracks, and also for use in coving areas.
Non-toxic: does not cause Occupational Health and Safety
Reduces the cement:water ratio, which results in a
As a temporary waterproofing sealer in high exposure
areas such as rooftops, while new waterproofing membrane is being installed.
When used under sheet membranes, it limits gassing.
As a slurry coat prior to applying renders or toppings.
As an admix for sand/cement mixes especially in repair
mortars, fillets, covings, renders and screeds.
As a bonding bridge for new to old concrete.
Do not use Ardex WPM 405 mortar to concrete slabs subject
to rising damp or hydrostatic pressure without first priming with Ardex WPM 300
(HydrEpoxy 300) in two coats at a coverage rate of 3 square metres per litre
per coat. Refer to the Ardex WPM 300 (HydrEpoxy 300) data sheet for screed
Protect Ardex WPM 405 liquid from frost - do not allow to
Do not apply Ardex WPM 405 as a temporary waterproofing
sealer if rain is imminent.
Do not apply if the surface temperature is below 10 0C or
above 35 0C.
Basic Application Instructions
The surface to be treated should be clean and sound, free
from oil, grease, laitance etc. New concrete should be allowed to cure for at
least 28 days prior to application of Ardex WPM 405 temporary waterproofing or
slurry coat. New brickwork walls, sand/cement render or screeds should be left
for at least 7 days before application of the Ardex WPM 405 temporary
waterproofing or slurry coat.
Temporary waterproofing: 1 part Ardex WPM 405: 2 parts
cement, (by volume).
Admix for render/screed/coving: Mix 1 Part Ardex WPM 405
with 4 parts water and use as the gauging mix (mixing water) with a 3:1 or 4:1
Slurry coat: 1 part Ardex WPM 405: 1 part water: 4 parts
cement (by volume).
Temporary waterproofing: Mix Ardex WPM 405 with fine
cement to a lump free consistency. Pre-moisten the concrete then apply a first
coat using a brush or roller to achieve 1mm wet bed thickness. Allow first coat
to set, then apply second coat at right angles to the first application to
ensure no pin-holing occurs. Liquid or sheet membranes can be applied directly
over this temporary waterproofing.
Slurry coat: Mix to a thin slurry and spread the mix over
the surface with brush or roller, or small broom. Maximum thickness recommended
is 2mm. While the slurry coat is still wet, apply render or screed over it.
Render/Coving: Apply slurry coat on the prepared surface.
While the slurry coat is wet apply the Ardex WPM 405 mortar mix with a wood
float trowel, ensuring firm pressure on the trowel to work the render into good
contact with the surface.
Screed: A minimum thickness of 15mm is recommended when
using diluted Ardex WPM 405 instead of water. For a thickness greater than
40mm, reinforcing mesh is required. Using a roller, brush or a flat trowel,
coat the prepared area with a slurry coat of Ardex WPM 405 to improve adhesion
to the substrate. Apply the screed mix whilst the slurry coat is still wet
using a straight edge, trowel or timber batten to level the screed. Achieve
falls in shower recesses to a minimum 1:60; internal wet areas (eg bathrooms)
to a minimum of 1:80; and external areas to a minimum of 1:100. Screeds should
be left with a wood float finish to create a key for tiling and waterproofing.
When reinforcing the screed with mesh, apply first layer of screed, lay in the
mesh and apply the second layer of the screed. Do not lay the mesh directly
onto the substrate.
Approximately 16 hours (overnight) at 23 0C and 50%
relative humidity when used for temporary waterproofing or render/screed.
Clean tools with water before the mortar dries.
Ardex WPM 405 is non-hazardous and non-dangerous goods.
Do not breathe gas/fumes/vapour/spray. Avoid contact with skin. Wear eye/face
protection. In case of contact with eyes, rinse with plenty of water and seek
medical advice. When used with mortar (which is alkaline) skin contact should
be avoided. Wear gloves and protective clothing.
Storage and Handling
Shelf life is approx. 12 months when stored in the
original unopened packaging in a dry place at 23 0C and 50% relative humidity.
Protect liquid from frost, do not allow to freeze.
20L covers 12m2 (2 coats at 1mm/coat)
1 litre – 3m2
As a render (15mm thick)
1 litre covers 2m2
a temporary waterproofing sealer
adhesion over concrete (7 days)
additive to screed