It is where they deck large areas higher than ground level ... and the neighbours feel it is encroaching on their privacy, or it is so large that it is almost like a building, and believe me some people do it on their own and do it unbelievably badly ! I am sure your company make a fine job of it rugeleyboy, but it is something to be aware of. Plus there are rules if children under 5 are using the decking about balustrades and the like, and multi level decking may not have the right loading and may contravene building regs.