Wrimco Waterproofing                              Home  | Specification | Product | Project | Technical data A-Z | Contact us

Adhesive Membrane

Anti-root Membrane

Approved Applicators

Backing Rod

Drainage Cell

Drainage Sheet

Epoxy Adhesive

Epoxy Flooring

Flat Roof Membrane  

Foundation Membrane

Liquid Membrane

Membrane Protection

Product Application

Product Category

Retaining Wall

SBS Sheet Membrane

Torch on Membrane

Under Slab Membrane

Vapour Barriers

Waterproofing Primer


Waterproof Balcony Liquid Membrane Waterproof Bathroom liquid membrane Waterproof Retaining Wall Liquid Rubber Membrane How to waterproof a bathroom Waterproof Internal Wet Area Membrane Waterproof Tiled Balcony Clear Penetrating Sealer Trafficable liquid membrane UV Protection liquid membrane Waterproof Water Feature liquid membrane Hydro Pressure Resistant liquid membrane Waterproof fish pond liquid membrane waterproof bathroom liquid membrane Waterproof above screed liquid membrane UV Resistant Polyurethane Membrane Waterproof leaking balcony liquid membrane waterproof damp basement wall liquid membrane Solutions to common waterproofing problems Maxseal Foundation Polyurethane Membrane MasterSeal M210TIX Latex Rubber Liquid Membrane Waterproof wet basement wall liquid membrane Injection Drill Pump Vulkem 350/345/346 Ardex WPM 300 Epoxy - Stop Rising Damp Waterproof Metal Roof Liquid Membrane Repair Leaking Balcony, Flat Roof, Planter Box, Bathroom Waterproofer, waterproof Leaking Balcony, Flat Roof, Planter Box, Bathroom tradesman, handyman Waterproof Box gutter liquid membrane Waterproof Retaining Wall liquid membrane Waterproof Internal, External Wall Liquid Membrane Waterproof Concrete Slab Liquid Membrane Waterproof Balcony Liquid Membrane Stop Leaking Shower Liquid Membrane How to waterproof a retaining wall How to waterproof a Retaining Wall How to fix leaking fish pond Waterproof Garage Roof Liquid Rubber Membrane Waterproof water tanks for drinkable water Waterproof Leaking Roof, Gutters, Balcony, Car Park tradesman Waterproof leaking box gutters tradesman Repair Leaking Balcony, Flat Roof, Planter Box, Bathroom Waterproofer   Repair Leaking Balcony, Flat Roof, Planter Box, Bathroom Waterproofer   HiBuild Hydrastatic Water based Epoxy Hydrostatic Negative Pressure Water Based Epoxy Under tile screed bed waterproofing membrane Prevent and Fix Rising Damp Waterproofing Epoxy Waterproof exposed balcony liquid membrane Repair leaking balcony waterproof liquid membrane Waterproof Bathroom Liquid Membrane Planter Box Retaining Wall Tanking Liquid Membrane Waterproof Leaking Metal Roof Waterproofer HOw to repair leaking fish pond Waterproof Underground wall Liquid Membrane Waterproof Planter Box liquid membrane Waterproof Watertanks Cementitious Liquid Membrane Waterproof Lift Pit Liquid Membrane ARDEX WPM 001 - Undertile Waterproofing Membrane Waterproof Planter Box Root Resistant Liquid Membrane Repair Bitumen Roof Waterproofing Liquid Membrane UV Protective Polyurethane Membrane Waterproof External Brick Wall liquid membrane Waterproof Retaining Wall Liquid Membrane Waterproof Planter Box Liquid Membrane Waterproof Wet Retaining Wall Liquid Membrane Waterproof Leaking External Wall Licensed Waterproofer Emer Clad Acrylic Liquid Membrane Waterproof Planter Box, Retaining wall liquid membrane Fast Cure Elastomeric Waterproofing Membrane Systems Waterproof Leaking Swimming pool tradesman UV Resistant Acrylic Liquid Membrane How to Waterproof a Leaking Metal Box Gutter Sikalastic 560 - Repair Bitumen membrane Roof Waterproof Lift Pits Tradesmen Waterproof Leaking Kitchen Tradesmen Waterproof Leaking Internal Basement Walls tradesman Waterproof Leaking Laundry tradesman Waterproof Leaking Deck, Verandah Tradesman Waterproof Leaking Roof, Gutters, Balcony, Car Park Tradesman, waterproofer, license waterproofer Repair Bitumen Roof Liquid Rubber Membrane Waterproof Besser Block Wall with Liquid Membrane Waterproof leaking bitumen roof contractors Waterproof leaking bitumen roof contractors  Waterproof Leaking Retaining Wall, Basement Wall Tradesmen Waterproof Leaking Ceiling Waterproofer Repair leaking Water Tank licensed Waterproofer Repair Leaking Fire Water Tank Licensed Waterproofer
Commercial Building Sheet Membrane Concrete Roof Sheet Membrane Waterproof Deck Sheet Membrane Entertainment building Waterproofing Membrane Waterproof Government Building Sheet Membrane Waterproof Hospital Building Sheet Membrane Waterproof Landmark Building Bitumen Membrane Waterproofing Planter Box Sheet Membrane Waterproof Plywood Roof Sheet Membrane Waterproof Residential Building Sheet Membrane Waterproof Roof Bitumen Sheet Membrane Waterproof Flat Roof Sheet Membrane Waterproof Retaining Wall Sheet Membrane Terrace waterproofing Sheet Membrane Waterproof University Building Sheet Membrane Wrimco Reference Waterproof Lift Pit Sheet Membrane Waterproof Concrete Roof Sheet Membrane Tanking Sheet Membrane Systems Vaucluse Waterproofing Project  Mosman Waterproofing Project Waterproofing Palm Beach Waterproofing Dover Height Waterproofing Darling Point Waterproofing Bellevue Hill waterproofing tradesman Knowledge Base FAQ Waterproofing Product Waterproof Leaking Garage Roof tradesman Repair SBS, APP Sheet Membrane Waterproof Concrete Slab Sheet Membrane Waterproof Leaking Garage Roof Liquid Rubber Membrane Waterproof Leaking Metal Roof Liquid Rubber Membrane Waterproof Balustrade Sheet Membrane Waterproof Commercial Building Project Bitumen Sheet Membrane Closed Cell Backing Rod Repair Crack Joints Closed cell backer rod Expansion joint backing rod Backing Rod Waterproof Leaking Roof, Balcony, Box Gutter tradesman Repair Leaking underground basement wall Waterproofer Waterproof Leaking Shower, Bathroom, Wet area Tradesman Repair Leaking Deck, Planter Box Waterproofer Waterproof Leaking Fish Pond Tradesman Waterproof Rising Damp Basement Tradesmen Roofs Waterproofed with Wrimco Sheet Membrane Waterproof Retaining walls with sheet membrane Waterproof Balcony with Sheet Membrane HDPE Self Adhesive Sheet Membrane Waterproof Commercial High Rise Building Roof Contractors Waterproof Car Park Roof with sheet membrane Ardex WPM 116 Sheet Membrane Ardex WPM 150 APP Sheet Membrane ARDEX WPM 188 SBS Garden Tanking Membrane ARDEX WPM 185 APP Sheet Membrane Ardex WPM320 Retaining Wall Sheet Membrane Waterproof Deck with torch applied Sheet Membrane ARDEX WPM612 FL TPO Fleece-Backed Roof Membrane TREMproof SBS 4000M Mineral Bituminous Membrane ARDEX WPM 1000 Weldable Waterproofing Membrane SBS Sheet Membrane Installation ARDEX WPM 3000X peel and stick membrane ARDEX WPM 750 Undertile Butynol  Waterproof Concrete Slab with Sheet Membrane ARDEX WPM 444 APP Sheet Membrane How to waterproof a Retaining wall How to waterproof a Planter Box How to waterproof a planter box How to waterproof Tiled Balcony with clear sealer How to waterproof a Shower  Ardex SRO 834 Waterproofing Specification Wrimco Sheet Membrane Waterproof elevator pits Sheet Membrane SBS Sheet Waterproofing Membrane How to waterproof balcony with sheet membrane Anti Root Sheet Membrane Vehicular Traffic Liquid Membrane Waterproof Planter Box with torch applied sheet membrane Waterproof Balconies Decks Podiums Prevent Rising Damp Hydro Static Epoxy How to waterproof a planter box 

Ardex WPM 405   Cement and Concrete Mixes   Additive   :  


Ardex WPM 405 (Sheltercrete Additive) High Performance Polymer Additive for Cement and Concrete Mixes

Product Description

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 concerns.

Reduces the cement:water ratio, which results in a stronger mortar/screed.


Typical Applications

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 installation details.

Protect Ardex WPM 405 liquid from frost - do not allow to freeze.

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


Surface preparation

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 sand/cement mix.

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.


Drying Time

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.


Safety Precautions

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.



Temporary waterproofing

20L covers 12m2 (2 coats at 1mm/coat)

Slurry coat

1 litre – 3m2

As a render (15mm thick)

1 litre covers 2m2


    Technical Data


Thin, white liquid

Specific gravity



9 – 10

As a temporary waterproofing sealer


Tensile adhesion over concrete (7 days)

1.5 MPa

Hydrostatic pressure resistance

0.34MPa (50 psi)

As additive to screed


Flexural strength


VOC content




Waterproofing FAQ

Membrane Protection Board

Waterproofing Coating

Waterproof Drainage Sheet

Waterproofing Primer

Repair and Maintenance