Dulux Water Based Primer, Sealer & Undercoat

Water based primer

Dulux 1 Step Prep is your first step toward a superior long lasting paint finish. Use Dulux 1 Step Prep for all general paint surfaces around your home and especially where mould is a problem.

With mould resistance and stain blocking of tannin and flash rust, Dulux® 1 Step® Prep ensures your interior or exterior paint shines now and into the future. 

Wondering how much paint you'll need? Try our handy paint calculator and we’re always here if you need to order more.

  • Category
    Interior Paints, Exterior Paints
  • Range
    1 Step
  • Brand
  • Designer
  • Year
  • Warranty
    2 weeks
  • Litres - available in 4 litre and 10 litre cans
  • Coverage - 14m2/L
  • Type - Interior, exterior
  • Range - 1 Step


  • Excellent coverage
  • Superior adhesion
  • Mould resistant
  • Recoatable with all systems
  • Water based
  • Multipurpose
  • Available in 500mL, 1L, 2L, 4L, 10L and 15L


  • Sticks to substrates increasing life of paint system
  • Helps resist mould growth
  • Use under acrylic or oil based topcoats
  • Easy clean up, low odour
  • One product primes, seals and undercoats
  • Environmental Choice approved
  • Made in New Zealand
Scope of use

Use Dulux® 1 Step® Prep for all general paint surfaces around your home including interior and exterior walls, ceilings, doors, windows, trim, and especially where mould is a problem including kitchens, bathrooms & outside areas.

Areas include - wall, furniture, cornice, window, trim, fretwork, awning, cupboard, gutter, ceiling, skirting, partitioning, column, window frame, banister, desk, door, architrave, balustrade, handrail, chair, fence, panelling.

Room space - apartment building, cladding, kitchen, lounge, residential property, study, bathroom, dining room, laundry, office, bedroom, hallway, living room, playroom

Application guide

Application method - brush, roller, spray

Clean up type - water

How to prepare

Painted and pre-primed surfaces:

  • Test if surface is sound (refer to surface test below).
  • Ensure surfaces are clean and stains are removed as much as possible by washing down with Selleys® Original Sugar Soap, using a scourer for any tough stains.
  • Scrape off all loose and flaking paint.
  • Fill any cracks or holes with a suitable filler. Sand filled areas and any rough surfaces to a smooth finish. Dust off. For very glossy surfaces, sand to a dull finish using 240 grit sandpaper. For pre-primed surfaces, contact Dulux Help & Advice. For chalky surfaces, sand back to a strongly bound surface and dust off.


  • Fill nail holes with a suitable flexible wood filler.
  • Sand the surface to reflect the final finish you desire. Sand any raised wood fibres to a smooth finish.
  • For very dark, tannin rich timbers, use Dulux 1 Step Oil Based. For pre-treated timber, check with the timber manufacturer for preparation and painting guidelines.

Galvanised iron & Zincalume®:

  • Clean with Selleys Original Sugar Soap to remove grease and dust. Thoroughly wash off with water and allow to dry.

Brick, masonry, fibro & fibre cement board:

  • Freshly laid masonry and cement based surfaces should be left to cure for minimum 28 days before painting. Ensure surface is sound and clear of any loose sand or cement. Wash down with water using a stiff brush to remove all loose material. Fill holes with grouting cement. To remove any efflorescence (white salts) wipe down with a 5% solution of acetic acid (white vinegar).

Surface test:

Ensure surface is sound by cutting a small X through the existing paint with a sharp blade, press cellulose tape firmly across the cut and then rip off the tape. If the paint comes off, it is unsound and should be removed. Repeat at random in a number of areas, to test the surface.

Check to see if there is any mould on the surface. If so, wash with a bleach solution (one part bleach, 3 parts water) or de-mossing chemical to remove mould or moss. Then wash with water. Refer to Dulux Help & Advice for further advice on surface preparation and product details.

How to apply:

Stir well with a broad flat paddle using an up and down scooping action. After following the surface preparation instructions, apply 1 coat of Dulux 1 Step Prep. If applying to new paperfaced plasterboard with jointing compound, a second coat may be required to ensure an even finish.

When painting exterior surfaces, ensure topcoat is applied no more than one week after application. Check the weather forecast. Do not paint on excessively cold or humid days. Exposure to rain or overnight dew whilst drying may result in the coating being damaged or removed.

Where to use:

Interior and exterior surfaces including paperfaced plasterboard, timber, MDF, brick, render, masonry, concrete, cement sheet, Zincalume®, galvanised iron, PVC and previously painted surfaces. For set plaster, use Dulux PRECISION® Sealer Binder.

Health and safety

Storage and disposal:

Unused paint: do not pour leftover paint down the drain. Unwanted paint should be brushed out on newspaper and allowed to dry, and then disposed of via domestic waste collections.

Empty paint containers: should be left open in a well ventilated area to dry out. When dry, recycle the container via steel can recycling programs. Disposal of empty paint containers via domestic recycling programs may differ between local authorities. Check with your local council first. For more information on responsible disposal of paint and packaging visit paintback.com.au

Clean up: water

Safety directions:

Keep out of reach of children. Avoid contact with skin and eyes or breathing vapour and spray mist (dust). Wear waterproof gloves and safety glasses. Use only in well ventilated areas. Wash hands after use.

First aid:

If poisoning occurs, contact a Doctor or Poisons Information Centre (Phone Australia 131 126: New Zealand 0800 764 766). If medical advice is needed, have product container or label at hand. SWALLOWED: If swallowed, rinse mouth. Do NOT induce vomiting. Give a glass of water. Call a POISON CENTRE or doctor/physician if you feel unwell.

Eye: if in eyes, hold eyes open, flush with running water for at least 15 minutes and see a doctor.

Skin: if skin or hair contact occurs, immediately remove any contaminated clothing and wash skin and hair thoroughly with running water. If swelling, redness, blistering or irritation occurs seek medical assistance.

Inhaled: remove from contaminated area – avoid becoming a casualty. Allow patient to assume most comfortable position and keep warm. Apply artificial respiration if not breathing. Seek medical advice.

For fire: if involved in a fire use alcohol resistant foam. If unavailable, use standard foam or dry agents. Avoid breathing products of combustion.

For spills: clear area of all unprotected personnel. Slippery when spilt. Wear protective equipment. Absorb with sand or soil. Collect and seal in properly labelled drums. Dispose of contents/container in accordance with local, regional, national and international regulations.


Environmental Certifications - Environmental Choice New Zealand Licensed, complies with the requirements for the Applied Coatings credts in Green Star New Zealand rating tools.

SKU: 630D0131 4L
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About the

Dulux has been part of the New Zealand community since 1939, and today we are the country's largest manufacturer of decorative paint products. Visit us here. Throughout our history we've led the way, creating products for New Zealand's unique conditions and formulated using only the highest quality materials.

Dulux offers an extensive range of products for commercial and residential projects including; interior, exterior, enamels, interior and exterior effects, metal protection, mould protection, prep coats, ceiling and textured coatings. Plus the majority of Dulux products carry the tick of approval from Eco Choice Aotearoa.

Dulux Colours of New Zealand is a range of 900 timeless and classic colours. The range is a journey through New Zealand and our homegrown colours with each colour inspired by a loved and cherished New Zealand location.