Flooring FAQs

Flooring FAQs

In addition to our office based Technical Department, we employ a highly experienced team of 25 Area Sales, Contract and Business Development Managers, who are available nationally to offer advice, support and training, not just over the phone, but in person and on-site. Our team answer thousands of questions every year, offering advice on a wide range of topics from subfloor preparation to the selection and application of our systems and products, and on our FAQ page, you'll find answers to the most common questions we're asked.

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For the latest technical or health and safety data on all ARDEX products, please consult the relevant technical or health and safety datasheet on our product pages.

Floor Preparation

I’m working on a 1960s property with thin vinyl floor tiles bonded to concrete with bitumen, can we leave the existing tiles and bitumen in situ as we have been advised they may contain traces of asbestos?

Some older vinyl tiles and mastics may contain asbestos. Please refer to the HSE guidance note a23 for more information.

I’m refurbishing an older domestic property with no structural DPM. I’ve removed the old floorcovering but a thin bitumen adhesive residue remains, what should I do?

Any remaining adhesive residues must be checked to ensure they are not water-softenable and that they are hard, sound and have enough cohesive strength to receive a levelling compound.

Where moisture-sensitive floorcoverings are to be installed the floor must be dry with less than 75% Relative Humidity (RH) when tested in accordance with BS 8203.

It's common for older properties built before the 1970s to not contain a structural damp proof membrane or to exhibit moisture readings up to 98% RH. In this instance, a pre-smoothing layer of ARDITEX NA followed by a suitable surface damp proof membrane such as ARDEX DPM 1 C is recommended.

ARDITEX NA can then be applied directly to the ARDEX DPM, up to 48 hours after application, to provide a surface ready to receive the floorcovering.

I’m replacing parquet flooring with LVT but when removing the parquet it’s leaving black, bitumen adhesive behind, what should I do?

Any remaining adhesive residues must be checked to ensure that they are not water-softenable and that they are hard, sound and have enough cohesive strength to receive a levelling compound.

Where moisture-sensitive floorcoverings are to be installed the floor must be dry with less than 75% Relative Humidity (RH) when tested in accordance with BS 8203.

It's common for older properties built before the 1970s to not contain a structural damp proof membrane or to exhibit moisture readings up to 98% RH. In this instance, a pre-smoothing layer of ARDITEX NA followed by a suitable surface damp proof membrane such as ARDEX DPM 1 C is recommended.

ARDITEX NA can then be applied directly to the ARDEX DPM, up to 48 hours after application, to provide a surface ready to receive the floorcovering.

I’m refurbishing a 1960s house with Marley Thermoplastic tiles on the floor, what should I do?

In domestic locations, ARDITEX NA can be applied directly as a nominal 2mm smoothing layer onto clean, suitably prepared, well-adhered and sound, homogeneous, thermoplastic and vinyl flooring which is a minimum of 2mm thick.

For more information please refer to the ARDITEX NA Datasheet.

I’ve removed some old ceramic tiles and the floor is covered in old tile adhesive, what should I do?

Ensure any old adhesive is sound and that the floor is free from dust prior to applying ARDITEX NA direct.

How do I prepare a new power floated concrete floor?

The surface should be mechanically prepared by abrasive techniques, such as scabbling or shot blasting, to expose a sound and clean surface with the aggregate within the concrete exposed.

How do I level a chipboard floor?

The British Standard for flooring, BS 8203, specifies that all timber bases should be covered with a suitable fabricated underlay such as plywood. For chipboard, it is recommended to securely cover with a minimum 5.5mm thick flooring grade plywood that complies with BS EN 636 and BS 8203.

Use ARDEX Feather Finish direct to treat any joints or rough patches, or to cover screw heads.

Levelling and Smoothing

What's the best ARDEX Levelling Compound for my project?

The type of levelling and smoothing compound required depends on the project and the condition and intended final use of the subfloor, for example, loads in service, use in domestic or commercial locations, abrasion resistance and cleaning regimes etc.

ARDEX manufacture a wide range of latex and water-based smoothing and levelling compounds ideal for all projects. Our range includes products suitable for internal and external use, quick-drying products which allow the floor to be walked on in as little as 1 hour for same-day turnarounds, and deep fill products ideal for levelling floors up to 50mm.

For problem floors, especially on refurbishment projects, ARDITEX NA provides the ultimate solution, with excellent adhesion to almost all substrates without the need to prime, including flooring grade plywood, ceramic tiles, steel, and even over old bitumen adhesive residue.

If you’re working alone the extended working time of ARDEX K 39 means fresh mixes can be easily smoothed into existing pre-applied material up to 40 minutes after application, giving you more time to create the perfect floor with no trowel marks, ridges, joint marks or additional preparation the next day.

For more information on the full range of products please click here.

Can I apply ARDEX Levelling Compounds over painted floors?

In general, “no”. A painted floor refers to anything on a floor that resembles paint and can include a variety of finishes ranging from acrylic or chlorinated rubber paints, which are generally used in domestic properties, to epoxy-based coatings more common in industrial locations.

Before applying an ARDEX Levelling Compound we recommend the removal of the “painted finish” to reveal a sound substrate without barriers to adhesion. This is because even though the ARDEX product may adhere to the “paint”, the bond of the “paint” to the substrate may not be strong enough and could lead to a failure in the floor.

In situations where a contractor deems the “painted finish” sound and wishes to apply ARDEX products directly to the “painted finish”, a trial area is always recommended and the contractor is accepting all responsibility that the bond of the “painted finish” is sufficient for the end-use.

Can ARDEX Levelling Compounds be painted?

Most ARDEX Levelling Compounds aren’t designed for use as a wearing surface, but ARDEX K 80 or ARDEX K 301 have been specially formulated for resurfacing and levelling existing concrete floors to give a hard, smooth, flat, wearing surface or as a base for suitable paint and resin coatings.

Can ARDEX Levelling Compounds be used on concrete garage floors?

Most ARDEX Levelling Compounds aren’t designed for use as a wearing surface, but ARDEX K 301 is ideal for resurfacing exterior concrete areas including domestic drives, paths and garages.

Does ARDITEX NA require priming?

ARDITEX NA can be used with confidence over almost all subfloors without priming including ceramic tiles, bitumen and flooring grade plywood. On absorbent surfaces, such as cement and sand screeds, it may be necessary to damp down the surface with water before applying ARDITEX NA, to help reduce suction and pinholes.

Prior to the application of ARDITEX NA, all calcium sulphate-based materials require priming. For more information please refer to our guidance note.

Can ARDITEX NA be applied over bitumen adhesive residues?

Yes, ARDITEX NA can be applied between 3mm-30mm, providing any remaining adhesive residues have been checked to ensure they are not water-softenable and that they are hard, sound and have enough cohesive strength to receive the levelling compound.

Can ARDITEX NA be applied over old ceramic tiles?

Yes, ARDITEX NA can be applied directly to ceramic tiles and terrazzo flooring after the surface has been degreased using a suitable degreaser.

Is ARDITEX NA moisture tolerant?

Yes, ARDITEX NA is moisture tolerant and can be applied directly to damp subfloors providing they are free of surface water. When used below an ARDEX Damp Proof Membrane ARDITEX NA will act as a pre-smoothing layer to ensure greater coverage and uniform application of the DPM.

Can ARDITEX NA be applied below a Damp Proof Membrane?

Yes, ARDITEX NA is moisture tolerant and can be applied directly to damp subfloors providing they are free of surface water. When used below an ARDEX Damp Proof Membrane ARDITEX NA will act as a pre-smoothing layer to ensure greater coverage and uniform application of the DPM.

Can I apply ARDITEX NA direct to steel?

Yes, the steel should be mechanically prepared by abrasive techniques or shot blasting to expose a sound, clean, rigid and shiny surface prior to applying ARDITEX NA from 3-6mm.

Can I use ARDEX Levelling Compounds outside?

Most ARDEX Levelling Compounds aren’t designed for external use, but ARDEX K 301 is ideal for resurfacing exterior concrete areas including domestic drives, paths and garages.

I need to level an anhydrite/gypsum-based screed. Do I need a special levelling compound?

Due to the risk of reaction and sulphate attack, cementitious materials should not come into direct contact with calcium sulphate-based material, so a priming barrier layer must always be used.

For more information please refer to our guidance note here.

For calcium sulphate screeds that are measured and deemed as dry, below 75% RH, simply follow these simple preparation steps.

Mechanically prepare the surface, removing all laitance, loose debris and dust to expose a sound hard surface.

In most cases ARDEX P 51 Primer, diluted 1:3 with water, can be used to prime the prepared surface, prior to applying any ARDEX Levelling and Smoothing Compound between 3mm to 6mm.

However, some screed manufacturers will specify that an epoxy-based primer is used so please check with the screed manufacturer before selecting the primer.

In this instance apply ARDEX R 3 E Primer and sand blind immediately with ARDEX Fine Aggregate. Once cured remove any excess aggregate and apply any ARDEX DPM 1 C , prior to the application of ARDITEX NA. This system can dramatically speed up the flooring installation process, helping you create the perfect floor in the shortest time possible.

For more information please refer to our guidance note and the relevant product datasheets.

How do I level calcium sulphate screeds?

For calcium sulphate screeds that are measured and deemed as dry, below 75% RH, simply follow these simple preparation steps.

Mechanically prepare the surface, removing all laitance, loose debris and dust to expose a sound hard surface.

In most cases ARDEX P 51 Primer, diluted 1:3 with water, can be used to prime the prepared surface, prior to applying any ARDEX Levelling and Smoothing Compound between 3mm to 6mm.

However, some screed manufacturers will specify that an epoxy-based primer is used so please check with the screed manufacturer before selecting the primer.

In this instance apply ARDEX R 3 E Primer and sand blind immediately with ARDEX Fine Aggregate. Once cured remove any excess aggregate and apply any ARDEX DPM 1 C, prior to the application of ARDITEX NA. This system can dramatically speed up the flooring installation process, helping you create the perfect floor in the shortest time possible.

For more information please refer to our guidance note and the relevant product datasheets.

Fast Track Repairs

We are currently working on an office refurbishment where we’re removing the existing walls. Can you recommend a product to fill the trenches and level any areas where the floor height may differ?

ARDEX manufacture a wide range of Repair Mortars ideal for the rapid repair of levelling and smoothing compounds, concrete and renders. ARDEX A 38 MIX is a pre-blended screed cement that can be used to repair large areas of existing sand/cement screed floors up to 65mm thick.

ARDURAPID A 45 is ideal for the rapid repair of internal concrete and screeds up to thicknesses of 50mm, while ARDEX A 950 can be used on deeper repairs of up to 100mm.

General

What advice can you offer for using ARDEX products during the winter months?

Cold weather impacts the feel and performance of all construction materials, in particular, setting and drying times which are likely to be extended.

All ARDEX products perform best at 20°C but have been engineered to work in real UK site conditions. The storage and installation temperatures are detailed in the Technical Datasheet of each product but generally, a minimum substrate temperature of 10°C, and an air temperature of 5°C and rising is required. For flooring applications, greater than 18°C is specified by BS 8203 and this temperature should be maintained for at least 48 hours before, during and after installation.

All ARDEX products must be protected from sub-zero temperatures and must not be allowed to freeze, so it’s important to take steps to protect materials.

Storing materials outside or in vehicles during the colder months will chill them, in which case pre-conditioning inside is recommended for 24-48 hours before use.

Ensure that after installation, ARDEX products are dried or fully cured prior to proceeding with subsequent installations and/or opening to traffic. Drying can be facilitated by using electric heaters or fans to circulate the air, but gas heaters should generally not be used as these contribute to raising the RH of the room. Do not blow air directly onto the substrate.

What advice can you offer for using ARDEX products in warm weather?

All ARDEX products have been engineered to work in real UK site conditions, but during higher temperatures or during prolonged sunny spells, precautions should be taken to minimise the impact the temperature may have, including rapid stiffening and hardening, a reduced working time and accelerated drying, which can lead to an increased risk of shrinkage and cracking.

Always ensure that ARDEX products are stored away from direct sunlight. Products stored outside must be shaded and protected from the elements. High temperatures can also drastically heat up materials stored in vans and other vehicles.

Always run the mix water until it is cool before using it to mix an ARDEX product. Hosepipes exposed to direct sunlight can heat water up rapidly, so they should be shaded. Water stored in buckets, water drums or other on-site methods should be avoided where possible.

Mix products in a shaded area to avoid the mixing tools becoming hot and ensure that tools are cleaned straight after use to avoid a build-up of material and contamination between mixes.

Warm surfaces will accelerate setting times, so a surface thermometer, infra-red or Protimeter MMS/2 machine, can be used to plan installation procedures. Tenting, shading and windbreaks, or working early in the morning can help control the substrate temperature.

In some cases, absorbent substrates such as concrete, aerated block, render, brickwork etc. may have higher porosity than under normal conditions. To help with application and reduce suction, consider damping down the surface with water or priming with 1 part of ARDEX P 51 Primer mixed with 7 parts water.

Consider reducing the size of your working area at the planning stage to ensure that the materials are installed as quickly as possible.

To reduce the increased risk of surface shrinkage, cracking, and differential drying, shade the working area and use temporary windbreaks. For screeded areas, an impervious protective sheet should be considered.