Resin flooring: cost per m², epoxy vs polyurethane, substrate and common mistakes

In short

A poured resin floor is a seamless layer of synthetic resin, most often epoxy or polyurethane, applied over concrete or screed. Epoxy is hard and resists chemicals well, polyurethane is more elastic, more comfortable underfoot and some systems cope better with UV light. Yet the choice of resin decides less about service life than the substrate: it has to be strong, mechanically prepared and dry enough. Most complaints, from bubbles to peeling, start right there. Current prices for the individual systems and for substrate preparation are listed in the flooring work category.

What makes up the price of a resin floor?

The price of a resin floor is not only about the pour itself. It is made up of several steps that are technically necessary, and each of them affects the final sum:

• Substrate preparation: grinding or shot blasting, crack repair, removal of weak layers and old coatings.
• Priming and levelling: floor priming before levelling and, on an uneven base, floor levelling.
• Type of system: thin coating, trowelled screed or self-levelling poured layer, epoxy or polyurethane.
• Design: plain colour, flakes, terrazzo or a marble effect.
• Top coat: matt or gloss sealer, anti-slip finish for wet areas.
• Area and access: on small areas the price per m² goes up, because the material is mixed in whole kits and preparation takes almost as long as on a bigger floor.
• Details: coved skirtings, movement joints, transitions to other floor finishes and fitting skirting boards.

As a guide, NUMIQ's price list puts a single-colour poured floor in polyurethane or epoxy up to 4 mm thick at roughly 70 to 100 € per m² depending on the region, including labour and the material of the poured layer, but excluding substrate preparation, priming and levelling. Decorative designs such as terrazzo or marble cost more. Current prices for all of these jobs, calculated from the live price list, are in the flooring work category.

Epoxy or polyurethane resin floor: which one suits better?

Both systems look similar at first sight, but their properties differ, and the wrong choice for the conditions leads to cracks, colour change or a floor that feels unpleasantly hard.

Epoxy resin floor

An epoxy resin floor is a common choice for garages, workshops, warehouses, shops and minimalist homes. It is hard, withstands abrasion and many chemicals well, and can be combined with decorative designs such as terrazzo or marble.

Epoxy is hard but less elastic: if the substrate moves or takes a heavy impact, it can crack. Standard epoxy resins change shade under long exposure to sunlight, so areas with direct sun and outdoor surfaces call for systems with a UV-stable top coat. The manufacturer's technical data sheet gives the specific recommendation.

Polyurethane resin floor

A polyurethane resin floor is more elastic, tolerates small movements of the substrate better and is more comfortable to walk on. Manufacturers offer, for example, systems laid on an elastic membrane with rubber granulate for sports and play areas, and decorative polyurethane systems declared as resistant to UV light and scratching. With polyurethane, an epoxy primer is often used as a bonding bridge to the substrate.

Polyurethane suits especially living spaces, spas, commercial interiors and anywhere comfort underfoot and appearance matter. According to Mapei, polyurethane systems tolerate a damper substrate better than epoxy, which usually needs a drier base or a damp-proof layer.

The substrate: what it has to meet

Resin floor manufacturers set strict substrate requirements in their technical data sheets. The data sheet of the widely used epoxy primer Sikafloor-161, for example, asks for:

• compressive strength of the concrete of at least 25 N/mm²,
• pull-off strength of at least 1.5 N/mm²,
• substrate moisture below 4 % by weight, measured with the carbide (CM) method or by oven drying,
• no rising damp, checked for example with a polyethylene sheet test,
• substrate and air temperature between 10 °C and 30 °C and relative air humidity of no more than 80 %,
• substrate temperature at least 3 °C above the dew point, otherwise moisture condenses on the surface and the resin bonds poorly.

The substrate must be mechanically prepared, for example by shot blasting or grinding, to remove the weak cement laitance and open the surface. Sweeping and priming alone are not enough. Values may differ by product, so the data sheet of the system the contractor actually uses always applies. Calcium sulphate (anhydrite) screeds, common in many European homes with underfloor heating, are far more sensitive to moisture than cement screeds and are usually only coated once their residual moisture is a fraction of a percent.

How the job is done step by step

1. Survey and measurement. The contractor measures the moisture and strength of the substrate, assesses cracks and flatness and, on a ground-bearing slab, checks whether the floor has a damp-proof membrane.

2. Substrate preparation. Grinding or shot blasting, vacuuming, crack repair. Remmers, for example, describes stitching cracks with stainless steel staples and filling them with epoxy.

3. Priming. The primer consolidates and seals the surface and ensures adhesion of the following layers. On an absorbent substrate it may be applied more than once.

4. Levelling or scratch coat, if the substrate is uneven, followed by another flatness check.

5. Poured layer. Resin and hardener are mixed in an exact ratio and applied within the pot life. Design systems get flakes or sand broadcast into them, anti-slip finishes get quartz sand.

6. Top coat and curing. Each following layer must be applied within the time window stated by the manufacturer. For Sikafloor-161 at 20 °C this is, for example, no sooner than 12 hours and no later than 2 days, and longer at lower temperatures. If the window is missed, the surface has to be sanded, otherwise the layers may not bond.

Where do resin floors pay off most?

Garages and workshops

Resin floors in a garage resist oil and chemical stains, carry the weight of a car, are easy to wash, and a seamless surface does not trap dirt. In a garage, an anti-slip finish and resistance to hot tyres matter, and in regions with winter road salt, so does resistance to salty meltwater. It pays to choose a system designed specifically for garages.

Commercial spaces and kitchens

In restaurants, shops and kitchens the advantage is a seamless surface that is easy to clean. For food businesses, the system has to be one the manufacturer declares suitable for that use.

Homes

In living rooms, hallways and kitchens, resin floors are chosen mainly for aesthetic reasons: a large area without joints looks clean and modern. Bear in mind that dust and fine scratches show on a glossy surface, and that in a block of flats impact sound also needs to be addressed. A comparison with tiles, vinyl or laminate is available in the flooring work category.

What happens in practice: the most common mistakes

Bubbles and blisters after some time. Mapei describes so-called osmotic blisters: moisture from the substrate gradually pushes under the cured layer and blisters appear only after weeks or months. Typical causes are damp concrete, rising damp from the ground or a ground floor without a damp-proof membrane. Prevention means measuring moisture before application and, on a damp substrate, choosing a suitable system, such as a moisture barrier or a vapour-permeable system.

Bubbles right after application. They come from air stirred in during mixing, from a porous substrate outgassing, or from the surface curing faster than the layer beneath, for example at high temperatures. Proper priming, a spiked roller and application within the prescribed temperatures help.

Peeling. This is almost always caused by poorly prepared substrate: laitance not removed, grease, dust or a weak screed. A substrate below the 1.5 N/mm² pull-off strength that typical data sheets require can tear away together with the floor.

Cracks transferred from the substrate. Cracks and movement joints in the concrete come through the thin resin layer to the surface. Movement joints have to be repeated in the resin floor and cracks repaired before pouring.

Sticky or soft spots. Poorly mixed components or the wrong ratio of resin to hardener. An experienced installer weighs and mixes exactly to the manufacturer's instructions and never prepares more than can be applied in time.

Condensation on the substrate. If the substrate is colder than the dew point plus 3 °C, for example in an unheated garage in autumn, the surface can turn cloudy, remain sticky or bond poorly.

What clients and contractors most often disagree about

• Appearance. A different shade between sections, visible joins or a different effect from the sample. An approved sample and an agreement on how the appearance is assessed (viewing distance, lighting) help.
• Bubbles after months. The contractor blames substrate moisture, the client blames poor workmanship. A written record of the moisture measurement taken before application settles who was right.
• What the price includes. Grinding, crack repair, levelling, skirtings and trims. Without an itemised quote they turn up as extras.

Checklist before signing and at handover

• Does the quote name a specific system and manufacturer, and is the technical data sheet part of the contract?
• Were the moisture and strength of the substrate measured, and do you have a written record?
• Is the method of substrate preparation (grinding, shot blasting) and crack repair agreed?
• Are the movement joints of the substrate repeated in the floor?
• Is the surface uniform, without bubbles, craters, sticky spots and visible joins?
• Is there an anti-slip finish where there will be water (bathroom, entrance, garage)?
• Do you have in writing when the floor may be walked on, when it can take full load and how to clean it?

How to decide on a resin floor

A resin floor is a practical and modern solution for homes and commercial spaces alike. With the right system and careful substrate preparation it will last a long time. Before ordering, check references from recent jobs, ideally by visiting a floor that has been in use for a year, and ask how the contractor measures substrate moisture and prepares the base. A contractor who cannot answer this specifically is a risk regardless of price.

FAQ - Frequently asked questions about resin floors

How much does a resin floor cost?

It depends on the system (epoxy or polyurethane), thickness, design, condition of the substrate and the area. Current prices for the individual systems and for substrate preparation, calculated from the live price list, are in the flooring work category.

What is the difference between an epoxy and a polyurethane resin floor?

An epoxy floor is harder and resistant to chemicals, but less elastic and may change shade in sunlight. Polyurethane is more elastic and more comfortable to walk on, suits living and commercial interiors, and some systems are declared UV-stable.

Is a resin floor suitable for a garage?

Yes, if the substrate is dry and strong and a system designed for garages with an anti-slip finish is chosen. For a garage slab laid directly on the ground, it is important to check that the concrete has no rising damp.

How long does a resin floor last?

Installed well and used properly, a resin floor lasts for many years. Service life is shortened mainly by mistakes in substrate preparation, moisture, UV light on an unsuitable system and mechanical damage from sharp objects.

How long does a resin floor take to dry before it can be walked on?

The time until the floor can be walked on and until it can take full load is stated in the manufacturer's data sheet and depends strongly on temperature. At lower temperatures all times get longer, so ask the contractor to put them in writing.

Can a resin floor be laid in a flat?

Yes, resin floors suit living rooms, kitchens and hallways. Bathrooms need a version with an anti-slip finish, and in a block of flats impact sound has to be considered as well.

Does a resin floor need special maintenance?

Usually wiping with a damp cloth and a neutral cleaner is enough. Aggressive cleaning agents and abrasive pastes dull the surface. Under heavy use, the top coat is renewed after some time as recommended by the manufacturer.

Work out the price of a resin floor for your project

The actual price depends on the system, condition of the substrate, area, layer thickness and design. Current prices are in the flooring work category.

Before you call the first flooring contractor, work out an indicative price for your project in the Numiq online calculator. You will get a realistic idea of market prices and a stronger position when negotiating with a contractor.

Start the Numiq calculator