How to lay a Stone Patio

Having a stone patio really is a great way to make the most of an outdoor space. And they are not just a summer pleasantry too, with patio heaters and covered outdoor tables there's no reason not to enjoy it all year round.

When planning your patio, the first thing to consider is location. Will it make effective use of sunlight? Will it allow adequate drainage? Will you want to walk 50 feet across your lawn to use it?

The construction of a patio requires 4 steps:

Preparation:

Get the area dug out and any retaining walls in place with adequate depth for sub base (6" or more) across the patio area. Work away from your finished flag level, or FFL. This should have been decided on during the planning of your patio, and allow water to drain off properly.

Sub Base and Surround:

Get your hardcore/blinding/crusher (it changes name depending whereabouts you are) in and compacted, preferably using a wacker plate to make sure it is consolidated. Also get any stone faced walls built up to height. This isn't necessary, but makes putting any overhanging edges on easier when you get to that stage.

Laying the Stone:

Plan your patio. If using mixed sizes of stone, make sure you have an equal mix to avoid one size being the dominant theme. If possible use feature stones ( I've used 1m square flags before, and my god are they heavy, but well worth it) to highlight any areas of interest.

Pointing up:

Its a boring job, but it makes all the difference. So do it properly the first time or else you'll have to go over it again!


There are so many options when it comes to what type of stone to use I won't even try to cover them. Every stone has its place, just as every client has their own tastes.

Personally, I'm quite familiar and fond of Indian limestone. Mainly because of its ready availability around my area, not to mention good price. As I said, its down to what the client wants, and what is available locally and complimentary to the surroundings.

So, location and stone chosen. Now a design must be decided upon.

Once again, a totally organic process which is down to you or you and your client to decide upon what works and what is practical. If a wall has to be put in place, make sure it is:

A) Complimentary with the type of patio you will be laying, e.g. stone types and colours must not clash but also not stick out like sore thumbs.

B) Designed to work with the wall - either have the flags covering the top of the wall as an edge, or have the wall finish at the patio height. Don't go hiding your patio from yourself!

Now then Lets get down to some nitty gritty stuff...

SUB BASE
This truly is the most important part of the job. And usually the most painful part. Any large patio requires at least 6" of compacted hard standing material, although if you are on solid bedrock then you can get away with less. The joy of using such a material is that you can put any slopes the patio may have into the base, and if you are careful you will use less mortar when it comes to bedding the flags.

Get it all carted in, one way or another. Wheelbarrow or bucket, there will always be a lot. Spread it out as best you can with a rake and, using a spirit level, put any contours in keeping a set distance below your finished flag level - usually around 4 inches.

A part wacked surface. This could do with at least 3 or 4 more passes.

Now you can fire up the wacker plate, and get deafened while following it around your sub base. You may find some areas consolidate more than others, so double check your levels. *If you need to top up with more sub base, rough up the area first with a rake before adding the fresh stuff*. If you don't, it won't bind together properly and may kick off or peel away when walked on to lay the patio.

If you find that mud/water is showing in some areas, dig them out. Dig out as much of the muddy soil as you can, and use lots more sub base in that area.

Now, after losing the majority of your hearing, you should have a lovely smooth surface to your sub base, ready to cover up with mortar and stone.

LAYING THE STONE
Start your cement mixer and get your mix on. I tend to use rendering sand, as I find it makes a nicer mortar than building sand. I also recommend using a plasticiser to help get a "fluffy" texture to the mix. It literally just puts bubbles in the mixture, but also makes a smoother more workable mix.

With the mix on, work out your starting point. Don't flag yourself into a corner! Start at a point far away from you, and always leave a path out. I usually go for around a 2 inch bed of mortar under each flag which hammers down to 1 1/2, and - get this - I DON'T DOT AND DAB.

 

You heard me, I put a full bed of mortar under each flag. That way I know there aren't any hollows and there's less risk of the stone coming loose in the future. (Also, after one job, there were damp patches "staining" the flags on each dot and dab point. The area that wasn't contacting the mortar dried much quicker and left 5 dark damp dots on each flag. Ahh well, you live, you learn right!)

If you have to make any cuts, do it from the bottom of the stone - the side which points downward. cut on an angle so the edge of the flag leans inward toward the bottom. To give a rough finish to the edge, use a hammer (stone hammer, lump hammer etc) to put a few chinks along the edge then run the head of the hammer along the corner a few times to rough it up.

POINTING UP
You knew this was going to happen. You had a whale of a time laying 40 square meters of stone, and now you feel sick looking at the miles of gaps which need filling in between each of them.

Well, invest in a pointing gun. Just like a giant syringe, you fill it with mortar, squeeze the copper nozzle to the width you require and point away. This saves A LOT of time. Believe me. You also realise how important it was to get the sub base at the correct height, so you have less depth underneath the flags. Yep, you find these things out the hard way. And even after reading this I bet you do it again anyway!

Once the pointing is in, leave it to go part-set. Once it has stiffened up, you can use your pointing trowel/tool, whatever you want to call it,(I've used the handle off an old land rover boot once - perfect width!) and finish off. Make sure you wipe up any spills with a damp cloth, as if you leave any to set on the flags you will have to acid etch it off which can leave horrible marks on some stone.


Congratulations! you have a patio! and if you used all the methods above you can probably park a tractor on it and she won't budge an inch. I do stress the probably part....