Sealing pavers helps to ensure they are protected from moisture entering the stone matrix, making cleaning easier and helping to prevent stains. Sealing also preserves their appearance and enhances their natural attributes and colours.
By taking a few straightforward preparatory actions, sealing pavers is easy to do. Before getting started, it is well worth talking to a paving supplier for recommendations on which sealant and other supplies to buy.
STEPS TO SEALING YOUR PAVERS
You need to make sure pavers are completely dry before any sealer is applied. Depending on the type of stone used, some pavers can be incredibly porous and moisture can be drawn to the surface of a paver from deep inside. Tape a piece of plastic wrap to a section of paving which is exposed to plenty of direct sunlight, and leave for two or three hours. If there is moisture on the plastic when you remove it later, your pavers aren’t dry enough yet.
Pavers should also be thoroughly cleaned before beginning the sealing process. A blower, broom or possibly even a pressure pump and/or high quality cleaning product designed specifically for pavers may be needed.
When pavers are clean and dry, application of the sealer is all that remains to be done. For a good result, sealer can be applied with a roller, brush or spray equipment. Two or three thin coats leads to a better result than one or two heavy coats and 24 hours drying time should be allowed between each coat.
Source: http://www.homeimprovementpages.com.au/article/sealing_your_pavers