Efflorescence and Other Weathering


  • Efflorescence appears on concrete paving slab products as white patches or a lightening of the surface colour, but seems to disappear when wet. It is formed by a normal chemical reaction between cement and water which causes calcium hydroxide (lime) to migrate through damp concrete to the paving surface and then react with carbon dioxide in the atmosphere resulting in a deposit of calcium carbonate crystals. Efflorescence is very unpredictable in its occurrence but is more prevalent in winter when concrete becomes wet and dries more slowly. Although there are cleaners available, efflorescence is a natural phenomenon and will generally disappear with the natural weathering process and the passage of time.
  • Simply Paving and Bradstone cannot accept responsibility for the effect of efflorescence which can be a characteristic of all good quality products with a high cement content.

Other Weathering

  • All decorative products will weather and change appearance over time.
  • Differential weathering can cause patchy dark discolourations on the surface of paviours, however, this will diminish over time and not affect long term performance.
  • All products can develop algae and organic growths under certain environmental conditions and subsequently may require cleaning.
  • Areas adjacent to borders, plant pots and trees may discolour from the transfer of plant life.
  • Specialist maintenance advice may need to be sort www.unitedstonecare.com.
Simply Paving, F Mill, Dean Clough Mills, 1st Floor, Halifax West Yorkshire, HX3 5AX. Registered office: Bardon Hill, Bardon Road, Coalville, Leicestershire, England, LE67 1TL © Simply Paving is a trading division of Aggregate Industries UK Limited, part of the Holcim Group of Companies. All rights reserved.