Crown Trade Fastflow Quick Dry Primer Undercoat White 1L

Crown Trade Fastflow Quick Dry Primer Undercoat is a water-based, 99% solvent-free primer undercoat for interior and exterior joinery and prepared metalwork. Touch dry in 1–2 hours and recoatable from 4 hours, this combined primer and undercoat is the recommended basecoat for the Crown Trade Fastflow system — providing the ideal foundation for Fastflow Quick Dry Gloss, Satin, and Eggshell top coats.

Part of Crown's Breatheasy range, this primer undercoat delivers excellent coverage at up to 15m² per litre, with low odour and smooth flow that feels like a traditional oil-based undercoat. Suitable for doors, windows, skirting boards, architraves, and prepared metal surfaces including radiators and pipework — both indoors and out.

Key benefits

• Combined primer and undercoat in one product — saves time and reduces coats needed
• Breatheasy formula — 99% solvent free with low odour, suitable for occupied buildings
• Touch dry in 1–2 hours, recoatable from 4 hours — keeps projects on schedule
• Coverage up to 15m² per litre depending on surface texture and porosity
• Excellent flow — applies and feels like a traditional oil-based undercoat
• Suitable for interior and exterior use on wood, metal, and PVCu
• BREEAM and LEED accredited

Best for

• Basecoat under Crown Trade Fastflow Quick Dry Gloss, Satin, or Eggshell
• Interior joinery — doors, skirting boards, architraves, window frames, and trim
• Exterior joinery — window sills, fascias, and door frames
• Prepared metal surfaces — radiators, pipework, railings, and gates
• PVCu surfaces with suitable preparation
• Occupied properties where low odour and fast drying are essential — housing, healthcare, education, offices
• Trade decorators, maintenance teams, and contractors needing same-day recoat capability

Key features – why it matters

• Dual-function primer undercoat: Combines primer and undercoat in a single product, reducing the number of coats and steps needed before applying your chosen Fastflow top coat. Saves time on site without compromising adhesion or finish.
• Formulated for the Fastflow system: Specifically developed to work with Crown Trade Fastflow Quick Dry Gloss, Satin, and Eggshell. Using it as part of the system helps achieve a smoother, higher-sheen top coat finish.
• Breatheasy 99% solvent-free formula: Very low odour during application and drying — reduces disruption in occupied spaces and is far more pleasant to work with than solvent-based undercoats.
• Quick dry performance: Touch dry in 1–2 hours and ready for a top coat from 4 hours under good conditions. Allows priming and first top coat in the same working day.
• Excellent coverage and flow: Spreads smoothly by brush, roller, or spray with up to 15m² per litre coverage. Applies like a traditional oil undercoat with good self-levelling properties.
• Interior and exterior use: Suitable for both internal trim and external joinery and metalwork, giving flexibility across a wide range of trade and DIY projects.
• BREEAM / LEED accredited: Meets recognised environmental standards for specification on sustainable construction and refurbishment projects.

Specifications

How to use

1. Ensure all surfaces are sound, dry, clean, and free from dirt, grease, dust, and loose or flaking paint.
2. On bare wood, treat knots with two coats of fresh knotting. Fill holes and defects with a suitable filler, sand smooth, and remove all dust. Apply one coat of Crown Trade Fastflow Quick Dry Primer Undercoat.
3. On bare or prepared metal, remove all rust and corrosion back to bright metal. Prime with a suitable metal primer (such as Crown Trade High Build Rust Inhibiting Primer or Crown Trade Water Based Metal Primer), then apply one coat of Fastflow Quick Dry Primer Undercoat.
4. On previously painted surfaces in good condition, wash with hot water and detergent, wet abrade glossy or eggshell finishes to provide a key, rinse with clean water, and allow to dry. Spot prime any bare areas with one coat of Fastflow Quick Dry Primer Undercoat.
5. Stir well before use. Apply with a good synthetic brush, microfibre medium pile roller, or spray system to achieve an even thickness. On timber, lay off in the direction of the grain.
6. To assist application on porous surfaces, the substrate may be dampened slightly.
7. Allow to dry fully before applying your chosen Fastflow top coat. Do not apply when the temperature is below 8°C or when relative humidity is above 80%.
8. Clean brushes and rollers with water immediately after use.

Care & safety

• Take additional precautions when preparing pre-1960s painted surfaces, which may contain lead.
• Do not apply in temperatures below 8°C or in damp conditions.
• Store in a cool, dry place. Protect from frost.
• Dispose of empty tins responsibly in accordance with local regulations.

Typical applications

• Basecoat for the Crown Trade Fastflow Quick Dry system on all interior and exterior trim
• Residential redecoration — doors, skirting, architraves, window frames, and radiators
• Commercial and contract decorating — offices, hotels, schools, hospitals, care homes
• Social housing and local authority maintenance programmes
• Exterior joinery — window sills, fascias, door frames, and gates
• New-build and refurbishment projects requiring BREEAM or LEED compliance

Delivery & returns

Free UK delivery on orders over £50. 28-day returns apply.

Why buy from London Decorators Merchants

• Independent, family-owned business with 16 decorating stores nationwide
• Trade-friendly service, support, and trade accounts available
• UK stock with fast dispatch
• Expert advice on Crown Trade products and decorating systems

Order online now or visit your nearest London Decorators Merchants branch for trade prices and expert advice.

FAQs

Is Crown Trade Fastflow Quick Dry Primer Undercoat water-based?

Yes. It uses Crown's Breatheasy formula, which is 99% solvent free. This means low odour, quick drying, and easy water clean-up — while still applying and feeling like a traditional oil-based undercoat.

How long does it take to dry before I can apply a top coat?

It is touch dry in 1–2 hours and recoatable from 4 hours under good conditions. This allows you to prime and apply a first top coat in the same working day. At lower temperatures or higher humidity, drying times will be longer.

Which top coats can I use over this primer undercoat?

It is specifically formulated for use with the Crown Trade Fastflow Quick Dry range — including Fastflow Quick Dry Gloss, Fastflow Quick Dry Satin, and Fastflow Quick Dry Eggshell. Using it as part of the system helps achieve the best possible top coat finish.

Can I use it over existing oil-based paint?

Yes, provided the existing paint is sound. Wash the surface with hot water and detergent, wet abrade any glossy or eggshell finishes to provide a key, rinse with clean water, and allow to dry fully before applying the primer undercoat.

What surfaces is it suitable for?

It is suitable for prepared interior and exterior wood, metal (ferrous and non-ferrous with appropriate priming), and PVCu. Common uses include doors, window frames, skirting boards, architraves, radiators, pipework, and railings.

Will one coat cover a dark colour underneath?

One coat is normally sufficient. However, over very dark colours you may need additional coats of primer undercoat to achieve full obliteration before applying your Fastflow top coat. Always check for colour accuracy before proceeding with the top coat.

Order by 2PM to get delivered next working day! We use 24 hours service with carriers in most cases so that you can get your order delivered on time.

There is £7.50 charge for delivery under £50 Orders. Additional charges will be imposed by our couriers for delivery to remote area, a surcharge may be levied to cover carriage to these areas.