Every time you lay a patio or path, you will need to cut paving stones. If you wish to trim down a paving stone in order to make it fit a corner or to make a circular pathway, you need not be too worried you are taking on a very hard task: cutting paving stones is easy in comparison to laying them and getting them to fit together in a professional manner.
Step 1 - Mark the Stone
Decide upon the stone you wish to cut and make a mark upon the paving stone where you intend to cut. Using a ruler, extend the line along the angle you wish to cut. Pick a paving stone that looks solid all the way through, so it is not likely to crumble when you begin to cut.
Step 2 - Check the Stone
Before you begin to cut the stone, make sure you have marked the line correctly by comparing it to the place where you wish to fit the stone. Lay the stone as closely to the space you wish to fit the stone as you can, and compare the angle on the ground with the angle on the stone. Once you have established it is the same, or at least very similar, you are ready to cut.
Step 3 - Practice
Handling a masonry saw can be quite difficult, so it may be a good idea to practice cutting a straight line on a piece of unwanted paving stone. If you have an old piece of patio, perhaps removed before you began laying this one, then this will make an ideal practice stone. Make a few passes with the saw on the practice stone before you try cutting a piece you intend to use in your patio.
Step 4 - Cut the Stone
Take a masonry saw which has a diamond tip-blade, and start to cut along the line you previously marked in the stone. Take care to follow the line as closely as you can, which might be quite difficult with a masonry saw in your hand. You should take care to add enough masonry sand to keep the saw cutting, but not too much, else the saw may become slippery. Be careful not to press too hard upon the saw, as this may cause a curved cut, and can even cause the saw to slip out of your hands. Pressing too hard will damage the straightness of the cut, making it difficult to fit cut paving stones together.
Step 5 - Finish the Stone
Once you have cut away the undesired piece of stone, place the newly trimmed paving slab in its place, and smooth the edges down with a piece of sandpaper. Smooth out the gaps between the stones with sand or masonry cement. Try and limit the gaps between the slabs to around three eighths of an inch, in order to keep them packed tightly enough together. If you do not cut the stones well enough, you could try chipping away flaws with a chisel or metal file.