Portland Stone paving has the advantages of excellent slip resistance and good durability, which is unusual for most Limestones and has therefore encouraged its use as a paving material. The shellier Whitbeds, such as Grove Whitbed, give a good texture and very natural appearance to the stone.
There are a number of factors that need to be considered by the designer, including the paver size and thickness, but most importantly the substrate that will provide the strength.
It is important that the base provides a solid foundation for the paving and where movement is a possibility it may be wise to use a reinforced strong concrete base.
Bedding and Grouting
It is imperative that only clean washed sand or course Portland stone dust and white cement are used in the bedding and the grouting and the addition of lime to make a lime mortar should also be considered as it is more flexible. It is important that any bedding or grouting doesn't stain the stone, so for example builders sand should not be used. There are a number of propriety pre-batched mortar mixes, but it is important to check that they are suitable for Portland Stone paving.
The stone should be laid by an experienced stone mason, not a general builder. The stones should be carefully handled and accurately laid with joints at 6mm +-1.5mm.
External paving provides one of the harshest environments for stone. Any stone used in this situation must perform well in a series of differing tests: Salt Crystallisation, Freeze Thaw test, Slip Resistance, Abrasive Resistance and the strength tests.
Annex B in BS EN 1341 provides the calculation of breaking loads for pavers. Our Paving Annex 1 provides the calculation for paving thickness. Please view it here
All products leaving our works are packed in a manner to ensure safe delivery to site.
After initial laying, the paving may dry inconsistently and a small proportion of organic compounds that are water soluble may migrate to the surface of the stone.
All porous stone paving is susceptible to damage by the application of de-icing salts or most chemicals onto ice already established on its surface.