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Ardex K55 FAST Ultra Rapid Drying Levelling and Smoothing Compound 20kg
Ardex K55 FAST Ultra Rapid Drying Levelling and Smoothing Compound 20kg

Ardex K55 FAST Ultra Rapid Drying Levelling and Smoothing Compound 20kg

Non-Stock 5-7 Working Days

Product Options:

Description

ARDEX K 55 FAST Ultra Rapid Drying Levelling and Smoothing Compound

ARDEX K 55 FAST is the newest and fastest addition to ARDEX’s Levelling & Smoothing Compound range, engineered for superior levelling performance and ultra-rapid drying. This high-performance, cement-based compound allows application from a feather edge up to 10mm in a single coat, making it ideal for fast-track installations and time-sensitive projects.

Walkable in just 30 minutes and ready to receive floorcoverings in as little as 60 minutes (at 20°C), ARDEX K 55 FAST combines outstanding flow, finish, and strength with exceptional speed. Perfect for both renovation and new-build applications, this levelling compound delivers a smooth, even surface ready for resilient and timber floorcoverings.

Key Features

  • Walkable in as little as 30 minutes.
  • Ready to receive floorcoverings in just 60 minutes (at 20°C).
  • Apply from a feather edge up to 10mm in one application.
  • Exceptional flow and surface finish – no patching or rubbing down required.
  • Rapid hardening and superior levelling performance with a 10-minute working time.
  • Excellent coverage – over 6m² at 2mm thick per 20kg bag.
  • Suitable for use over underfloor heating systems.
  • Low embodied carbon: 0.96 kg CO₂ eq/kg (A1-A3 as defined in BS EN 15804).

Product Applications

ARDEX K 55 FAST is designed to level and smooth internal subfloors in a single application within a 10-minute working time. It is suitable for:

  • Smoothing uneven, damaged or worn in-situ concrete subfloors.
  • Adjusting tolerances or camber differences between floors, slabs or pre-cast concrete.
  • Renovation of existing subfloors and screeds prior to installation of resilient floorcoverings such as vinyl, linoleum, or carpet.
  • Use over heated screeds, provided they are commissioned as per BS 8204 Part 1 and BS EN 1264.

Note: ARDEX K 55 FAST is not intended to be used as a wearing surface.

Technical Data

Property Result
Working Time (20°C) Approx. 10 minutes
Walkability (20°C) Approx. 30 minutes
Ready to Receive Floorcoverings (20°C) Approx. 60 minutes*
Application Thickness Feather edge to 10mm
Coverage Approx. 6.2m² at 2mm thickness per 20kg bag (1.62kg/m²/mm)
Weight of Fresh Mortar Approx. 1.96kg/litre
Compressive Strength After 1 day: 20 N/mm²
After 7 days: 30 N/mm²
After 28 days: 35 N/mm²
Tensile Bending Strength After 1 day: 6 N/mm²
After 7 days: 8 N/mm²
After 28 days: 10 N/mm²
Suitable for Underfloor Heating Yes
Embodied Carbon (A1–A3) 0.96 kg CO₂ eq/kg
Packaging 20kg paper sacks with polyethylene liner
Storage / Shelf Life 6 months in unopened packaging, stored in cool, dry conditions

*Dependent on substrate, application thickness, adhesive type, and ambient temperature.

Application Instructions

Pour the mixed ARDEX K 55 FAST onto the prepared subfloor and allow it to flow to a smooth finish within its 10-minute working time. Use a steel finishing float or long-handled smoothing trowel for best results. A spiked roller can also be used immediately after application to eliminate air bubbles.

Underfloor Heating Applications

Heated screeds must comply with BS 8204 Part 1 and BS EN 1264. The underfloor heating system should be fully commissioned and cooled to room temperature (not below 15°C) before applying ARDEX K 55 FAST. After installation, the system should be gradually brought up to operating temperature to prevent thermal shock.

Frequently Asked Questions (FAQ)

How quickly can I walk on ARDEX K 55 FAST after application?

ARDEX K 55 FAST can be walked on in as little as 30 minutes at 20°C, allowing for rapid progress on-site.

When can I install floorcoverings over ARDEX K 55 FAST?

Floorcoverings can typically be installed in as little as 60 minutes, depending on temperature, substrate, and layer thickness.

Is ARDEX K 55 FAST suitable for use with underfloor heating systems?

Yes, ARDEX K 55 FAST is suitable for use over underfloor heating systems when installed in accordance with BS 8204 Part 1 and BS EN 1264.

What is the coverage rate for ARDEX K 55 FAST?

A 20kg bag covers approximately 6.2m² at 2mm thickness or 4m² at 3mm thickness.

Can ARDEX K 55 FAST be used as a finished wearing surface?

No, ARDEX K 55 FAST is not designed as a wearing surface and should always be covered with a suitable floorcovering.

Delivery & Returns

Delivery Information

Delivery Costs:

Delivery fees are calculated based on the weight of your order and your delivery location. You can use the delivery fee calculator in your basket or on the checkout page to find the exact cost.

Delivery Area:

We currently only deliver to UK Mainland and the Highlands. We do not deliver to the Islands, Ireland, or Northern Ireland.

Next Working Day Delivery (Subject to Stock Availability):

Orders placed before 12:00 pm (noon) will be delivered the next working day, excluding weekends and holidays. This service starts from £6.50 (including VAT) and the final cost is based on the weight of your order and your delivery location. You can check the exact cost in your shopping cart or on the checkout page by entering your postcode.

Cut-off Time for Genesis Products (Non-Stocked): 11:00 am

NO Next Day Service - Scotland:

We are unable to offer next-day service to the following postcode regions in Scotland.

Postcode: AB, IV, KW, PA .

Economy Service (2-3 Working Days):

This service is only available for orders over 50kg. There is no additional charge for this service.

Sample Orders:

All sample orders are shipped for free via Royal Mail Tracked 48 or 24 service. Delivery typically takes 1-3 working days.

Delivery Methods:

Non-sample orders under 50kg will be dispatched via DPD or APC Overnight. Non-sample orders over 50kg (quarter, half, and full pallets) will be dispatched via Palletways or Kandrmason (Kerbside delivery only).

Order Online & Collect In-Store!

Simply place your order online and choose the Click & Collect option at checkout.

We'll email you once your order is ready for pickup at your chosen store.

Collection hours: Monday - Friday: 8:30 am to 4:30 pm

For more information, please visit our Delivery Information page.

Returns Information
  • Please inspect your order upon receipt and contact us immediately (within 48 hours of receipt) if the item is defective, damaged, or if you receive the wrong item, so that we may evaluate the issue and make it right.
  • We will replace any items that are damaged during transit within 30 days of delivery.
  • We accept returns within 30 days of delivery.
  • Please note that customers are responsible for the cost of returning items where the return is due to a change of mind, including ordering the wrong item, ordering more than required, or any other non-fault reason
  • We will process returns and refunds promptly once the items are received at our warehouse.

Returning Trims

Schluter Trims:

  • Returning trims - 35% restocking fee applied.
  • Returning trim with replacement - 15% restocking fee applied.
  • Customers are responsible for arranging the return.
  • If we arrange a return collection, a £35 return item collection fee will be applied.

Mapei-Profilpas Trims:

  • A 20% restocking fee will be applied (item must be in re-sellable condition).
  • The customer is responsible for returning the item.

For more information, please visit our Return & Exchange page.

Delivery Costs:

Delivery fees are calculated based on the weight of your order and your delivery location. You can use the delivery fee calculator in your basket or on the checkout page to find the exact cost.


Delivery Area:

We currently only deliver to UK Mainland and the Highlands. We do not deliver to the Islands, Ireland, or Northern Ireland.


Next Working Day Delivery (Subject to Stock Availability):

Orders placed before 12:00 pm (noon) will be delivered the next working day, excluding weekends and holidays. This service starts from £6.50 (including VAT) and the final cost is based on the weight of your order and your delivery location. You can check the exact cost in your shopping cart or on the checkout page by entering your postcode.


Cut-off Time for Genesis Products (Non-Stocked): 11:00am


Economy Service (2-3 Working Days):

This service is only available for orders over 50kg. There is no additional charge for this service.


Sample Orders:

All sample orders are shipped for free via Royal Mail Tracked 48 or 24 service. Delivery typically takes 1-3 working days.


Delivery Methods:

Non-sample orders under 50kg will be dispatched via DPD or APC Overnight. Non-sample orders over 50kg (quarter, half, and full pallets) will be dispatched via Palletways or Kandrmason (curbside delivery only).


ORDER ONLINE & COLLECT IN-STORE!

Simply place your order online and choose the Click & Collect option at checkout.
We'll email you once your order is ready for pickup at your chosen store.
Collection hours: Monday - Friday: 8:30 am to 4:30 pm


For more information, please visit our Delivery Information page.

- Please inspect your order for any damages upon delivery and notify us immediately if you find any.

- We will replace any items that are damaged during transit.

- We accept returns within 30 days of delivery.

- Please note that customers are responsible for the cost of returning items.

- We will process returns and refunds promptly once the items are received at our warehouse.


Returning Trims
Schluter Trime
Returning trims - 35% restocking fees applied.
Returnign trim with replacement - 15% restocking fees applied
Customers are responsible to arrange returning the item.
If we arrange a return colleciton, a £35 return item collection feed will be applied.


Mapei-Profilpas Trims
A 20% restocking fee will be applied. (Item must be in re-sellable condition)
The customer is responsible for returning the item.


For more information, please visit our Return & Exchange page.