ARDEX W 820 SUPERFINISH – Universal Finishing Plaster

ARDEX W 820 SUPERFINISH is a brilliant white, polymer-modified gypsum finishing compound designed for filling, smoothing, and finishing interior walls and ceilings in dry areas. Its rapid hardening formulation allows finishes the very next day, while its extended 3-hour pot life makes it ideal for larger areas and fast-track installations. Apply by roller, spray, or trowel for an ultra-smooth, professional-grade surface finish.

Non-combustible (Class A1 under EN 13501) and compliant with EN 13963:2014 and EN 13279-1, ARDEX W 820 SUPERFINISH offers excellent versatility, ease of use, and consistent performance across a wide range of substrates and applications.

Key Features

• Apply by roller, spray, or trowel for versatile installation
• 3-hour pot life – perfect for larger surfaces and projects
• Receives paint or wallpaper finishes the next day
• Can be applied from a feather edge up to 20mm in a single coat
• Easy to mix, apply, and sand smooth
• Slump-free and clean application – no overspray
• Suitable for decorative surface design techniques
• Non-combustible (A1 rating) and low embodied carbon (0.49 kg CO₂ eq/kg)

Where to Use

ARDEX W 820 SUPERFINISH is ideal for smoothing, jointing, and finishing interior walls and ceilings in dry areas. It can be applied by roller, hand, or spray on a variety of substrates, including:

• Plasterboards and pre-rendered walls
• Concrete and aerated concrete
• Lightweight and construction boards
• Gypsum plaster surfaces
• Prefabricated concrete slabs and filled joints

Mixing Instructions

Mixing ratios vary by application method. Always use clean water and tools.

• Roller Application: Mix 14.75–16 L of water per 25 kg bag. Use a coarse pile roller (20 mm) and apply vertically, then horizontally for the second coat.
• Spray Application: Mix 12.5–14 L of water per 25 kg bag. Use a suitable spray nozzle (535–543 for thin coats, 243 for filling joints). Continuous cleaning between mixes is essential.
• Hand Application: Mix 11–12.5 L of water per 25 kg bag. Apply using a trowel, blade, or filling knife and smooth with a straight edge or steel float.

Allow the product to stand for 2–3 minutes after mixing, then remix to a creamy, lump-free consistency before applying. Apply at temperatures above 5°C.

Application & Finishing

• Apply from feather edge up to 20mm thick in one coat
• Minimum thickness for full surface skimming: 3mm
• Surface dry in 5–6 hours at 20°C (10mm thickness)
• Ready to receive finishes after full drying – typically within 24 hours
• Sand or re-trowel once surface has hardened for an ultra-smooth finish

Coverage

• Approx. 14 m² @ 2mm (roller application)
• Approx. 9 m² @ 3mm (spray application)
• Approx. 26 m² @ 1mm (hand application)

Technical Data

Packaging & Storage

• Supplied in 25 kg paper sacks with polyethylene lining
• Store in original packaging, off the ground, in cool and dry conditions
• Shelf life: 12 months (sealed and properly stored)
• Ensure part-used bags are tightly resealed to prevent moisture ingress

Frequently Asked Questions

1. Can ARDEX W 820 SUPERFINISH be applied by hand?

Yes, it can be applied manually using a trowel or filling knife, making it versatile for both small and large areas.

2. How long does it take to dry before painting or wallpapering?

Under typical conditions (20°C), surfaces are ready to receive decorative finishes within 5–6 hours for thin layers and fully dry within 24 hours.

3. What is the maximum thickness per coat?

ARDEX W 820 SUPERFINISH can be applied up to 20 mm in one application, or feathered to zero for seamless transitions.

4. Can it be used for decorative effects?

Yes, the product can be used to create various decorative textures and finishes. Always conduct a small trial before full application.

5. What tools are recommended for application?

Use a steel trowel, smoothing blade, spray machine, or coarse roller (20 mm pile) depending on your chosen method.

6. Does it require a primer?

No primer is typically required on most sound, clean, and dry substrates. However, test adhesion on challenging surfaces before full application.

7. How should leftover mixed material be handled?

Do not reuse material that has begun to harden. Clean tools and mixing equipment between batches to maintain working time and consistency.

8. What is the environmental impact of ARDEX W 820?

It has a low embodied carbon footprint of 0.49 kg CO₂ eq/kg, making it an environmentally responsible choice for interior finishing projects.