KNOWLEDGE BASE / POLYUREA
Polyurea. A material that creates continuous protection.
The spray-applied membrane follows the surface geometry. Its suitability depends on the specific product, substrate preparation and service conditions.
01 / FROM CHEMISTRY TO COATING
What is polyurea?
This family of materials is formed by the reaction of an isocyanate component with an amine component. In spray systems, the components are metered and mixed by the equipment, and the reaction produces a flexible, continuous coating on the structure. Pure polyurea and polyurethane–polyurea hybrids have different compositions; the name "polyurea" alone does not define a complete set of properties.
A polyurea membrane provides waterproofing or surface protection; the roof's thermal and moisture performance is designed separately. This page explains material selection. For the preparation and application process, see our description of HOWLER technology.
Pure or hybrid
Compare the data sheets for the finished products. Hybrid systems are developed for specific tasks; their suitability depends on the properties of the finished coating.
Aromatic or aliphatic
This distinction matters, among other things, for appearance under sunlight. Aromatic membranes can change colour under UV exposure. Where colour stability matters, we select an appropriate finish coating.
The membrane and the entire system
Adhesion to the substrate, primer, membrane and finish must work together. A test result for one product cannot be applied to an arbitrary combination of layers.
02 / ADVANTAGES AND LIMITATIONS
What you gain.
What needs attention.
Possibilities
- Continuity on a complex surface. Spraying allows a layer to follow surfaces and details without the laps typical of sheet membranes.
- Rapid progress on site. A short reaction time can reduce downtime. Gel time, however, does not tell you when a pool may be filled.
- Accommodating substrate movement. Certain products have tested crack-bridging ability and abrasion resistance. A moving expansion joint still requires an appropriate detail.
Conditions for success
- The substrate must be suitable for coating. Before application, we assess the substrate's strength, cleanliness and moisture content. Rising damp requires its cause to be addressed; spraying alone does not eliminate it.
- Spray application requires control. Mixing ratio, equipment condition and pore sealing matter. Incorrect application can leave pores or uncured material.
- Exposure must be defined. Temperature, chemicals, UV and traffic determine system selection. No single material offers universal resistance to everything.
03 / SERVICE CONDITIONS
Where to consider it.
Where to check first.
Roofs and terraces
A solution worth considering where there are many penetrations and complex shapes. Existing layers, drainage, moisture and the required finish of the exposed surface must be assessed.
See applicationPools and basins
Selection must account for permanent immersion and the actual water treatment method. The time before filling, preparation before use and permitted cleaning agents are specified for the particular system.
See applicationSteel and sheet metal
A coating can protect a prepared metal surface. It is not a way to seal over active corrosion: the condition of the sheet metal, joints and existing protection must be assessed first.
See applicationProcess tanks
The name of the liquid is not enough. Assessment requires its concentration, temperature, contact time and cleaning conditions. A test result for one mixture does not describe every process medium.
See applicationWastewater treatment plants
Immersion, splash and the atmosphere above wastewater must be assessed separately. We check the selected system's resistance to the actual environment, including the possible presence of biogenic sulphuric acid. Not every membrane is suitable for every zone of a wastewater treatment plant.
See applicationZoos and animal pools
The starting point is the type of water, contact with animals and the facility maintenance procedure. A document for drinking water or a swimming pool does not by itself confirm every zoological use.
See applicationWhen should the decision wait?
When the substrate is weak or damp, the structure needs repair, chemical exposure is unknown or the required water contact has not been confirmed. Assessment and system selection come first; a material quotation follows.
04 / EXPLORE EACH LAYER'S ROLE
Four substrates.
Five options.
Rotate the model, zoom in and separate the layers. The list shows the work sequence, while the model distinguishes material layers from preparation operations. Thicknesses and spacing are illustrative.
LAYER DIAGRAM / 3D
Roof on a concrete substrate
A waterproofing build-up on concrete. Falls, drainage, movement joints and the remaining roof components require separate detailing.
Drag horizontally to rotate. Select a stage to highlight a layer or the surface being prepared. Keyboard controls are also available.
- Layer
A sound substrate whose condition has been assessed. Voids and structural damage require repair before waterproofing.
- Operation
Removal of contamination. Before the next stage, the substrate must dry to meet the conditions required for the selected system.
- LayerOptional
Optional levelling of local irregularities and filling of voids with a suitable material.
- Layer
The first coat of primer, selected for the substrate and membrane. It prepares the surface for the subsequent stages.
- LayerOptional
Optional repeat priming if required by the substrate condition or the selected build-up.
- OperationOptional
Optional broadcasting of sand onto the appropriate coat, followed by removal of loose excess before further work.
- Layer
A continuous spray-applied membrane. Material selection and application quality control take account of the surface's intended use and its details.
- LayerOptional
An optional coating selected for the exposure, desired appearance and service conditions.
Illustrative diagram, not to scale. Preparation operations are not separate material layers. Stages marked “Optional” are used according to the substrate, intended use and compatibility of the selected build-up.
TWO OPTIONS FOR BITUMINOUS ROOFING
Roof over an existing bituminous membrane
The choice depends on the condition of the existing roof and the selected solution. Each option requires substrate preparation and a compatibility check for the successive materials.
LAYER DIAGRAM / 3D
Bituminous roofing with a foam layer
An option with a required closed-cell foam layer. Suitability requires assessment of the existing bituminous membrane, moisture and adhesion of the complete build-up.
Drag horizontally to rotate. Select a stage to highlight a layer or the surface being prepared. Keyboard controls are also available.
- Layer
An assessed and prepared bituminous membrane. Detached, damaged and damp areas must be dealt with before work begins.
- Operation
Removal of contamination. Before the next stage, the substrate must dry to meet the conditions required for the selected system.
- Layer
A required foam layer suitable for the selected roof build-up and for covering with the membrane.
- Layer
A continuous spray-applied membrane. Material selection and application quality control take account of the surface's intended use and its details.
- LayerOptional
An optional coating selected for the exposure, desired appearance and service conditions.
Illustrative diagram, not to scale. Preparation operations are not separate material layers. Stages marked “Optional” are used according to the substrate, intended use and compatibility of the selected build-up.
LAYER DIAGRAM / 3D
Bituminous roofing with polyurea
An option without a foam layer, using a primer on the existing substrate. Adhesion and material compatibility are checked on the actual surface.
Drag horizontally to rotate. Select a stage to highlight a layer or the surface being prepared. Keyboard controls are also available.
- Layer
An assessed and prepared bituminous membrane. Detached, damaged and damp areas must be dealt with before work begins.
- Operation
Removal of contamination. Before the next stage, the substrate must dry to meet the conditions required for the selected system.
- Layer
A primer selected for the existing bituminous membrane and the next coating. It does not replace repairs to weak or detached areas.
- OperationOptional
Optional broadcasting of sand onto the appropriate coat, followed by removal of loose excess before further work.
- Layer
A continuous spray-applied membrane. Material selection and application quality control take account of the surface's intended use and its details.
- LayerOptional
An optional coating selected for the exposure, desired appearance and service conditions.
Illustrative diagram, not to scale. Preparation operations are not separate material layers. Stages marked “Optional” are used according to the substrate, intended use and compatibility of the selected build-up.
LAYER DIAGRAM / 3D
Roof on a steel substrate
A protective build-up for sheet-metal roofing. The condition of the corrosion protection, welds, edges, fasteners and overlaps is assessed before application.
Drag horizontally to rotate. Select a stage to highlight a layer or the surface being prepared. Keyboard controls are also available.
- Layer
Prepared steel whose condition has been checked. Corrosion and damage must be removed or repaired before applying new coatings.
- Operation
Removal of contamination. Before the next stage, the substrate must dry to meet the conditions required for the selected system.
- Layer
Corrosion protection compatible with the substrate type and subsequent layers.
- LayerOptional
An optional additional primer coat specified in the selected build-up.
- OperationOptional
Optional broadcasting of sand onto the appropriate coat, followed by removal of loose excess before further work.
- Layer
A continuous spray-applied membrane. Material selection and application quality control take account of the surface's intended use and its details.
- LayerOptional
An optional coating selected for the exposure, desired appearance and service conditions.
Illustrative diagram, not to scale. Preparation operations are not separate material layers. Stages marked “Optional” are used according to the substrate, intended use and compatibility of the selected build-up.
LAYER DIAGRAM / 3D
Base of a basin or tank
A waterproofing build-up on a mineral substrate. Membrane and finish selection take account of the tank contents, cleaning method and water contact conditions.
Drag horizontally to rotate. Select a stage to highlight a layer or the surface being prepared. Keyboard controls are also available.
- Layer
An assessed mineral substrate. Cracks, corners, wall junctions and penetrations require preparation and suitable detailing.
- Operation
Removal of contamination. Before the next stage, the substrate must dry to meet the conditions required for the selected system.
- OperationOptional
Optional mechanical surface preparation. Dust and loose residues are removed after treatment.
- Layer
Priming the prepared substrate with a material compatible with the subsequent layers.
- Layer
A second primer coat in the illustrated build-up. Application and overcoating conditions are established for the selected materials.
- OperationOptional
Optional broadcasting of sand onto the appropriate coat, followed by removal of loose excess before further work.
- Layer
A continuous spray-applied membrane. Material selection and application quality control take account of the surface's intended use and its details.
- LayerOptional
An optional coating selected for the exposure, desired appearance and service conditions.
- LayerOptional
An optional finish for the contact surface or to provide slip resistance, according to the basin's intended use.
Illustrative diagram, not to scale. Preparation operations are not separate material layers. Stages marked “Optional” are used according to the substrate, intended use and compatibility of the selected build-up.
05 / COMPARISON OF SOLUTIONS
Selection, not a ranking.
No technology is best for every facility. This comparison outlines how the systems work and the key decisions involved; it does not replace comparing quotations with the same scope.
| Solution | When it is useful | What needs attention |
|---|---|---|
| Spray-applied polyurea | Continuous on-site coating, efficiently covering complex geometries. | Metering and spraying equipment, substrate preparation and application control. Properties depend on the formulation. |
| Polyurethane (PU) membrane | This can also be seamless. Cold-applied products are available and can be convenient for detailing. | The number of layers, reinforcement and setting times depend on the product. Not every PU is a replacement for sprayed polyurea. |
| Roofing felt and bituminous membranes | Sheet systems with base sheets and cap sheets. Torch-applied and self-adhesive versions are available. | Laps and detailing are among the factors that determine the result. Not all roofing felt requires a flame, and not every existing system can be overlaid. |
| Cementitious waterproofing | A solution for mineral substrates, including balcony and swimming pool systems. Hand application is possible. | Flexibility, detailing and the intended finish must be selected. Waterproofing mortar is not a universal chemical protection for steel. |
| EPDM | Prefabricated elastomeric sheets. The system includes a membrane, fastening and accessories for flashings and connections. | Jointing requires the appropriate primers and tapes, or another method specified by the manufacturer. Terminations and edges matter. |
| PVC | Prefabricated sheets, joined by hot-air welding in typical roofing systems. | Seam checks, layer compatibility and designed fastening are required. The joining method for PVC must not be applied to EPDM. |
06 / SCOPE AND COST
Polyurea: what affects the price per m²?
The cost of installing polyurea waterproofing covers more than spraying alone. We quote for the specific structure and agreed scope of work. A material price in the shop is not the installed price per square metre of a complete system.
Discuss an installation quote- Substrate and preparation: the condition of existing layers, required cleaning, repairs and priming.
- Geometry and access: area, number of details, outlets, movement joints and conditions for organising the work.
- System and use: membrane and finish selected for water, UV, traffic and other actual loads.
07 / QUESTIONS BEFORE DECIDING
A clear description of the facility
makes the selection easier.
Prepare information.
Provide the substrate type and condition, existing layers, intended use, tank contents and acceptable downtime. Include overview photos, close-ups and available documentation. We can then determine what inspections or tests are needed.
Discuss system selectionIs each coating safe for water and animals?
This cannot be inferred from the resin's name. Confirmation is needed for the specific material, use and contact conditions. We assess drinking water, pool water and animal environments separately; approval for one does not automatically apply to all these situations.
Does rapid curing remove health and safety requirements?
No. Before reacting, the components have different properties from the finished coating. Spraying requires suitable operator protection and ventilation. We select safeguards for the materials, process and workplace, particularly inside tanks.
Can service life and a price per metre be given from the name alone?
No. Service life depends on the complete system, workmanship, exposure and maintenance. Cost also includes preparation and detailing. Compare the scope of work and warranty terms, not just the membrane name or resin price.