What substrates does Multiprime work on?

Multiprime bonds to concrete, render, fibre-cement, screeds, and most porous and semi-porous substrates. It is the standard primer for ARDEX waterproofing membranes and levelling compounds.

How long does Multiprime take to dry?

Multiprime is touch-dry in 30-60 minutes and ready to overcoat with membrane or levelling compound in 1-2 hours under normal conditions.

What is the coverage rate?

Multiprime achieves approximately 6-10 m² per litre on smooth concrete, and 4-8 m² per litre on porous or absorbent substrates. Apply one even coat by brush, roller, or broom.

Is Multiprime water-based and low-odour?

Yes. Multiprime is a water-based, solvent-free primer with no solvent hazard, suitable for indoor and occupied building use.

Do I dilute Multiprime?

Multiprime is supplied ready-to-use for most substrates. Highly porous surfaces may benefit from a first coat diluted 1:1 with clean water, followed by a neat second coat.

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Ardex Multiprime

$253.20

or 4 interest-free payments with

Water based primer for concrete, render, screed, CFC and AAC. Dry in 15 to 30 minutes, inside or out.

ARDEX Multiprime is a water-based, low VOC primer that improves the bond of approved ARDEX products to porous substrates. Shake it, brush or roll it on, and it is dry in 15 to 30 minutes at 23°C and 50% RH. White, ready to use, no dilution.

Where to use it

Concrete, render, screed, masonry and concrete blocks
CFC sheet and jointing compound over plasterboard
Autoclaved aerated concrete (AAC), two coats
Internal and external, before approved ARDEX products

Why waterproofers buy it

Water based, low VOC
Quick drying, 15 to 30 minutes
Brush, roller or sponge
One coat on most substrates. Second coat only on very porous surfaces like AAC
Improves adhesion to various substrates
Tools wash up in water and detergent before it dries
ARDEX 10 year product guarantee

Coverage

One litre covers approximately 8 to 9 m². Coverage varies with the porosity of the surface and how you put it on. 20L drum.

Not for

Ambient or substrate temperatures below 10°C or above 35°C, thinning with water or solvent, or when rain is imminent. It is a primer, not a moisture barrier. Where concrete moisture is over 80% RH (ASTM F2170) or 15 g/m²/24hrs (ASTM F1869), use a minimum two coats of ARDEX WPM 300 instead.

Drying time at 23°C and 50% RH.

Water-based with low VOC content

Covers approximately 8 to 9 m2 per litre and dries in 15 to 30 minutes

Primes CFC sheet, concrete, render, screed, masonry, concrete blocks and AAC

Size: 20 Lt

20 Lt$253.204 Lt$58.801 Lt$24.95

Quantity: 1

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Pickup available at The Waterproofing Shop

Usually ready in 24 hours

Ardex Multiprime

20 Lt

The Waterproofing Shop

Pickup available, usually ready in 24 hours

22/872 Canterbury Road
Roselands NSW 2196
Australia

+61280213517

How to Use

Shake the contents thoroughly, then apply by brush, roller or sponge to the prepared substrate at approximately 8 to 9 m2 per litreMechanically prepare and vacuum clean the substrate to remove all dirt, dust, curing compounds, oils, grease, surface sealers, existing coatings and any other contaminants
Leave the surface sound, clean, dry and free from sharp edges and loose material
Treat damaged concrete between 2mm and 30mm with ARDEX A 46
Treat spalling concrete with the ARDEX Concrete Repair range such as ARDEX BR 345
Measure substrate moisture; where it exceeds 80% relative humidity (ASTM F2170) or 15gms/m2/24hrs (ASTM F1869), use a minimum two coats of ARDEX WPM 300 as the nominated primer instead
Confirm ambient and substrate temperature is at or above 10C and not above 35C, and that rain is not imminent
Shake the contents thoroughly before application
Apply by brush, roller or sponge to the prepared substrate
Apply a second coat on very porous substrates such as autoclaved aerated concrete
Allow 15 to 30 minutes drying at 23C and 50% RH, longer where substrate type, porosity or weather conditions demand it
Confirm ARDEX Multiprime is completely dry before applying subsequent ARDEX products
Clean all equipment with water and detergent before the product dries

Technical Specifications

Product Type: Water-based primer, low VOC content
Colour: White
Form: Liquid
Appearance: White milky liquid with a slight odour, mixes with water
pH (as supplied): 8.0
Shore Hardness A: 90*
Specific Gravity: 1.19g/cm3*
Service Temperature: 0C to 80C*
Tensile Strength (Min): 5.03 MPa*
Drying Time: 15 to 30 minutes at 23C, 50% RH
Coverage: Approximately 8 to 9 m2 per litre
Number of Coats: One coat; a second coat on very porous substrates such as autoclaved aerated concrete
Application Temperature: Not below 10C and not above 35C, ambient and substrate
Dilution: None permitted - do not add solvent or water
Packaging: 20L drum
Clean Up: Water and detergent before the product dries
Shelf Life: 12 months unopened, stored dry at 23C and 50% RH
Hazard Classification: Hazardous Chemical, Non-Dangerous Goods; Sensitisation (Skin) Category 1
* Nominal values published by ARDEX with no test method quoted

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Ardex Multiprime20 Lt

$253.20

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Technical overview

ARDEX Multiprime is a water-based, low VOC primer used to improve the adhesion of approved ARDEX products to porous substrates including CFC sheet, jointing compound over plasterboard, concrete, render, screed, masonry, concrete blocks and autoclaved aerated concrete. It is applied by brush, roller or sponge and dries in 15 to 30 minutes at 23C and 50% RH, with one litre covering approximately 8 to 9 m2. It is a primer, not a moisture barrier. Where masonry or concrete substrate moisture is greater than 80% relative humidity (ASTM F2170) or exceeds 15gms/m2/24hrs (ASTM F1869), ARDEX require a minimum two coats of ARDEX WPM 300 as the nominated primer instead. The data sheet cites no Australian Standard classification and no accredited test report; the published figures are nominal values.

View full technical data sheet

Key applications

Priming porous substrates to improve adhesion of approved ARDEX products
Priming CFC sheet
Priming jointing compound over plasterboard
Priming concrete, render and screed
Priming masonry and concrete blocks
Priming autoclaved aerated concrete (AAC), two coats
Internal and external priming

Surface suitability

CFC sheet
Jointing compound over plasterboard
Concrete (sound, clean, dry, free of curing compounds, oils, surface sealers and existing coatings)
Render
Screed
Masonry
Concrete blocks
Autoclaved aerated concrete (AAC) (a second coat of ARDEX Multiprime is required)

Do not apply if ambient or substrate temperature is below 10C or above 35C. Do not add solvent or water to the product. Do not apply if rain is imminent. It is a primer, not a moisture barrier: where masonry or concrete substrate moisture is greater than 80% relative humidity (ASTM F2170) or exceeds 15gms/m2/24hrs (ASTM F1869), a minimum two coats of ARDEX WPM 300 (HydrEpoxy) must be the nominated primer instead. Ensure the primer is completely dry before applying subsequent ARDEX products. Classified a Hazardous Chemical: may cause an allergic skin reaction, so wear protective gloves, protective clothing, eye protection and face protection and do not breathe mist, vapours or spray.

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Ardex Multiprime

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Technical Specifications

Product Type	Water-based primer, low VOC content
Colour	White
Form	Liquid
Appearance	White milky liquid with a slight odour, mixes with water
pH (as supplied)	8.0
Shore Hardness A	90*
Specific Gravity	1.19g/cm3*
Service Temperature	0C to 80C*
Tensile Strength (Min)	5.03 MPa*
Drying Time	15 to 30 minutes at 23C, 50% RH
Coverage	Approximately 8 to 9 m2 per litre
Number of Coats	One coat; a second coat on very porous substrates such as autoclaved aerated concrete
Application Temperature	Not below 10C and not above 35C, ambient and substrate
Dilution	None permitted - do not add solvent or water
Packaging	20L drum
Clean Up	Water and detergent before the product dries
Shelf Life	12 months unopened, stored dry at 23C and 50% RH
Hazard Classification	Hazardous Chemical, Non-Dangerous Goods; Sensitisation (Skin) Category 1
* Nominal values published by ARDEX with no test method quoted

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Frequently asked questions

View all FAQs

What substrates does Multiprime work on?

Compatibility
Multiprime bonds to concrete, render, fibre-cement, screeds, and most porous and semi-porous substrates. It is the standard primer for ARDEX waterproofing membranes and levelling compounds.
How long does Multiprime take to dry?

Performance
Multiprime is touch-dry in 30-60 minutes and ready to overcoat with membrane or levelling compound in 1-2 hours under normal conditions.
What is the coverage rate?

Installation
Multiprime achieves approximately 6-10 m² per litre on smooth concrete, and 4-8 m² per litre on porous or absorbent substrates. Apply one even coat by brush, roller, or broom.
Is Multiprime water-based and low-odour?

Compliance
Yes. Multiprime is a water-based, solvent-free primer with no solvent hazard, suitable for indoor and occupied building use.
Do I dilute Multiprime?

Compatibility
Multiprime is supplied ready-to-use for most substrates. Highly porous surfaces may benefit from a first coat diluted 1:1 with clean water, followed by a neat second coat.

Why trade professionals choose Ardex

Ardex is a global leader in high-performance building products, trusted by Australian trade professionals. The range spans liquid and sheet waterproofing membranes, primers, sealers, screeds and repair systems, engineered for lasting results on residential and commercial projects.

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