I spend a lot of time scouring the paving expert website. It's a fantastic resource for anybody looking for any type of advice or information about paving and groundwork's. The site is used by a broad range of people from DIY'ers with no experience of paving right up to the most experienced and knowledgeable tradespeople you could hope to find.
As a stone supplier my interest in the paving expert website is to try and give sound independent advice about natural stone paving and its usages. One subject that keeps coming up is that of using a bond bridge when installing natural stone paving. Before I started using the paving expert website I had never even heard of a bond bridge. A bond bridge is essential when using natural stone paving which has low porosity levels. Materials like slate and Granite Paving fall into this category. These types of stone are very dense and don't absorb moisture as much as other stones like sandstone do. A bond bridge is a slurry of cement and sbr (very sticky stuff) which is painted onto the back of the slabs. This then creates a bridge in between stone and bedding layer which massively aids adhesion. If you are installing granite or Slate Paving it is essential that a bond bridge is used. It can also be used with Sandstone Paving as an extra precaution but in my experience of laying sandstone a bond bridge is not necessary