What is a polyurethane floor?
Polyurethane coatings are formed by the reaction of a polyol with an isocyanate curing agent; besides solvent-free products, there are also water-based two-component polyurethanes. Unlike rigid epoxy, polyurethane remains flexible: the coating absorbs impact and vibration, bridges hairline cracks in the substrate, and is softer and quieter underfoot. Aliphatic polyurethanes do not yellow in light, which is why UV-resistant topcoats are made from them.
Polyurethane floors are laid in workshops subject to vibration and temperature changes, in warehouses, in retail, educational and medical premises where walking comfort and noise reduction matter, and on stands and walkways. A polyurethane topcoat is often applied over an epoxy system to protect it from UV, give the surface a matt finish or make cleaning easier.
Types
Flexible self-levelling systems
Solvent-free self-levelling products from fractions of a millimetre to several millimetres thick — 0.4 to 4 mm for the materials in the catalogue. The manufacturer states the ability to bridge cracks and to stretch without tearing in the data sheet, and materials are compared on this basis. Such floors are chosen for slabs subject to deflection and vibration, and for rooms where the floor should be softer and quieter than an epoxy one.
Wear-resistant coatings and broadcast systems
Harder polyurethanes and polyurethane-epoxy hybrids combine abrasion resistance with moderate flexibility. With a broadcast of quartz sand, they are used to make slip-resistant systems for ramps, walkways and decks where the coating is exposed to temperature changes.
Topcoats
Thin polyurethane varnishes and enamels — gloss, matt, clear or pigmented; for the materials in the catalogue, this means tens of micrometres per coat. Their tasks are UV and wear resistance, the required gloss level, less visible scratching and easy cleaning. Water-based topcoats have almost no odour and are convenient in premises that remain in operation.
Car parks, ramps and open decks
Multi-layer polyurethane systems are used for car park decks and trafficked roofs: a flexible waterproofing membrane bridges cracks in the slab, a wear-resistant broadcast layer gives tyre grip, and an aliphatic topcoat protects against UV. Such systems are designed taking into account temperature changes and the water and salts brought in on wheels, so their build-up is specified according to the manufacturer’s system data sheet.
Comfort and sports floors
Multi-layer systems with a resilient underlay or a thick elastic layer for schools, hospitals, offices and sports halls. They are chosen for comfort, sound insulation and wear resistance under foot traffic; they are not designed for vehicles and forklifts.
How to choose a polyurethane system
Hardness or flexibility
The softer the coating, the better it copes with impact, cracks and vibration, but the worse it withstands point loads — rack feet, pallet trucks, hot tyres. Compare the Shore hardness, elongation and crack-bridging ability stated in the data sheets.
Light and appearance
For rooms with windows, showrooms and halls where colour matters, topcoats based on aliphatic polyurethane are chosen. Matt topcoats hide scratches and wheel marks better, while gloss ones are easier to clean.
Moisture during application
The isocyanate curing agent reacts with water. On a damp substrate, in high air humidity or with condensation, bubbles and pinholes form in the layer and the surface loses its gloss. The maximum moisture of the substrate and the air and the margin above the dew point are taken from the data sheet.
Loads and temperature
For forklifts and heavy trolleys, the elastic layer must be of sufficient thickness and strength, and for hot areas it must have heat resistance confirmed by the data sheet. Where the floor is washed with hot water and steam, polyurethane cement systems are usually chosen.
Chemicals and cleaning
Polyurethanes resist water, cleaning agents, oils and many dilute solutions, but resistance to a specific substance is checked against the manufacturer’s data sheet. Resistance to the specific medium is confirmed by our questionnaire: substance, concentration, temperature and regime.
Typical systems
- Flexible floor: epoxy primer, a levelling coat where necessary, a flexible polyurethane self-levelling layer, a matt polyurethane topcoat.
- Epoxy floor protected from light: an epoxy system of the required thickness with an aliphatic polyurethane topcoat over it.
- Slip-resistant floor: primer, a polyurethane or hybrid layer with a quartz sand broadcast, and a polyurethane sealing coat.
The build-up, thicknesses and order of layers are taken from the manufacturer’s system data sheet: a topcoat of one brand over a main layer of another is acceptable only where compatibility has been confirmed.
Application specifics
- The substrate is dry, its temperature is above the dew point by the margin given in the data sheet, and there are no dust-laden draughts in the room.
- The mixing ratio is strictly by weight or volume as per the data sheet; kits are not split.
- Working with isocyanates requires ventilation and respiratory and skin protection in accordance with the safety data sheet.
- Matt topcoats are sensitive to application technique: they are rolled “wet on wet” without letting the edges dry, otherwise streaks remain.
- Colour may vary slightly between batches — use material from a single batch for one area.
Common mistakes
- Application to damp concrete or in wet weather — bubbles, craters, loss of gloss.
- A soft elastic floor under racking with point loads — dents and indentation.
- An aromatic polyurethane topcoat in an area exposed to sunlight — yellowing.
- One manufacturer’s topcoat over another’s system without a compatibility check — delamination.
- Too thick a topcoat in one pass — wrinkling, slow curing.
- Washing and traffic before the curing time given in the data sheet.
See also: resin flooring — overview, epoxy floors, polyurethane cement floors.
Materials in the catalogue
- Sikafloor-330 — Sika — elastic low-VOC polyurethane self-smoothing wearing layer for Sika ComfortFloor systems.
- Sikafloor-305 W — Sika — water-based matt coloured polyurethane seal coat for ComfortFloor and epoxy systems.
- Jotafloor PU Topcoat — Jotun — non-yellowing polyurethane floor topcoat for sunlit areas, 50–80 µm per coat.
- Jotafloor PU Universal — Jotun — elastic self-levelling solvent-free polyurethane, waterproof intermediate layer 0.4–4 mm.
- Mapefloor PU 470 — Mapei — semi-elastic aromatic polyurethane resin for self-levelling and multi-layer industrial floors.
- TEKNOFLOOR 660F — Teknos — elastic solvent-free polyurethane floor coating, 0.5–2 mm, bridges cracks up to 1.7 mm.
This list is not exhaustive. The final choice is made on the basis of the manufacturer’s documents and the project requirements.
Frequently asked questions
Is a polyurethane floor better than an epoxy one?
It is neither better nor worse — just different. Polyurethane wins where flexibility and resistance to impact and UV are needed; epoxy wins where maximum hardness and abrasion resistance are needed at a moderate price.
Can polyurethane be applied over an old epoxy floor?
Yes, if the old coating is firmly bonded: it is cleaned, degreased and sanded, and then a material whose data sheet specifies such preparation is applied. A trial area with an adhesion test is essential.
Why have bubbles appeared on my polyurethane floor?
Most often because of moisture: the isocyanate reacts with water from the substrate or the air, releasing gas. The second cause is air escaping from the pores of the concrete if the coating is applied while the substrate is warming up. That is why the moisture content of the concrete is measured in advance, the pores are sealed with a primer, and the self-levelling layer is laid when the substrate temperature is stable or falling.
What is a matt topcoat for?
A matt surface produces less glare, and scratches, wheel marks and substrate irregularities are less visible on it. It is chosen for retail and public premises and for floors that need to look neat for a long time.
We will select a polyurethane system or topcoat for your floor — call us or message us on WhatsApp/Telegram: +998 94 094 52 27.