Polyurea Resins

Polyurea Resin Based Bund Lining Systems

Disadvantages and Limitations of Polyurea Systems

Some of the beneficial properties offered by polyurea elastomeric coatings can also pose some issues that may be a disadvantage for some projects such as:

• Application can be nozzle operator dependent and as it is fast this must be monitored closely.
• Fast curing can mean insufficient ‘wetting’ of the substrate if this is not assessed, prepared and where necessary primed correctly to ensure optimum adhesion.
• Although tolerant of damp conditions, polyurea systems should not be applied on ‘wet’ surfaces so again good Quality Control on site must be maintained.
• Polyurea systems require specialist application techniques and the selected contractor must have full training from the manufacturer of the products and the expensive equipment required.
• Due to all of the above contraints, limited comparative and competitive pricing can be made, so the correct advice and selection of the right polyurea system and competent specialist contractor is essential.
• Poyurea coatings are designed to be protective rather than aesthetic, so the sprayed finish can have an ‘orange-peel’ effect and in UV light they can discolour – although this does not affect the protective performance.
• Therefore for all of the above advantages and the prevention of any issues on site, getting the right advice and support from the polyurea coating and lining specialists at NCC Bund Lining is also an essential pre-requisite for successful completion and durability of your bund lining and containment projects.

Application Requirements and Characteristics of Polyurea Resins

Substrate - As with all resin bases bund lining and protective coating systems, the concrete substrate must be sound and of sufficient compressive strength (minimum 25 MPa), with a minimum pull-off strength of 1.5 N/mm². Any unsound or damaged concrete must be removed and repaired, plus any surface defects such as blowholes and voids must be fully exposed and repaired with suitable compatible products.

Important Note: NCC Bund Lining can advise on these too and have a large amount of these repair materials in stock at our depots around the country.

Moisture content - Prior to application of polyurea resin systems the substrate moisture content must be < 4% , the relative humidity should also be checked and recorded, so that dew point conditions can be avoided. If the moisture content is more than > 4%, then application of the polyurea coating can only proceed when the moisture level reaches an acceptable level, or a temporary moisture barrier such as Sika EpoCem technology, is applied and then the work will be able to proceed the next day, once this barrier layer has hardened sufficiently.

Substrate Preparation - Concrete substrates must be cleaned and then mechanically prepared using abrasive blast cleaning for example, to remove any cement laitance, existing coatings and to achieve a fine gripping profile that is clean, dry and free from laitance, dirt, grease, oil and any other form of surface contamination.

Application - Polyurea systems require installation by trained and experienced contractors as in the end, the person at the spray gun is mostly responsible for the quality level that is achieved, which is why the whole process must be monitored. The selected contractors operatives must all be adequately trained and instructed in a project specific Quality Control process that will lead to the best possible results.

The specialists at NCC can advise you on the most suitable polyurea resin systems, trained Specialist Contractors (please also see the ‘Specialist Contractors’ Page of this website), for your specific bund lining project needs. Please call any of our offices for assistance from our experts.