How To Landscaping - Regular Paving





  1. Prepare your site (see SITE PREP guide)
  2. Mark out the shape of your patio on the ground with surveyors paint, pegs and string, or a simple sand line.
  3. Run a set of pegs along the outside edges of your patio, these pegs will mark the level and fall of your patio (see SETTING OUT), the fall of the patio may vary according to the slabs you are using, the ground conditions around the patio and nearby buildings a good general guide is to aim for a 1:50 fall this equates to a drop of 2cm every metre.
  4. You can now begin digging out your patio to 17.5cm (7") below the level you want your finished patio, check the levels within your patio area regularly, if necessary you can add additional pegs to this area to help you check.
  5. Once the patio has been dug out and your levels are all correct you can put down a geotextile stabilisation membrane, this will reduce the risk of rutting or sinkage.
  6. On top of the membrane add 10cm (4") of mot type 1.
  7. The mot type 1 must now be thoroughly consolidated (wackered) with a vibrating plate (wacker plate).
  8. The base is now complete, mix up your first batch of mortar (see the MIXING guide) and lay the first slab (see laying guide in the notes below), the first slab will normally be laid in the furthest point from your access route. You may like to run string lines out from the first slab to set an accurate edge and fall for the laying of subsequent slabs.
  9. You can now begin to lay the rest of the slabs, pay close attention to any layout patterns you are following as well as the level of the slabs according to your pegs and their relation to each other. You must also pay attention to the joints between the slabs, if you are laying them butt jointed (pushed up against each other), make sure they are tight. If you are going to have a pointed joint you should check that the joints are even (usually 10mm thick).
  10. As you lay check that no excessive quantities of mortar are sticking up between the gaps you'll need to leave them at least 1.5cm deep to ensure an adequately strong joint can be made and smooth of all visible edges of the patio, filling voids in the edges as you go round. 
  11. When you've finished laying, have a last look at your work, then leave the patio overnight to firm up.
  12. Now that the patio has firmed up you can begin pointing (take care with the slabs, the mortar will not yet have fully hardened and until you have pointed the joints they are at risk of being knock out of position). Mix up another batch of mortar, if you are using a pointing gun follow the manufacturers instructions, otherwise you can mix it by hand, using a suitable vessel such as a measuring jug to gauge the quantities. Pour 4 soft (building) sand and 1 cement into a bucket and mix them thoroughly with a trowel. Pour in a small amount of water to make the mix slightly damp and binding, but not wet and sticky. It is important to ensure you mix the same proportions each time, otherwise the colour won't match. It is also important not to mix too much, or it will begin to set before you have used it up.
  13. Kneeling next to a joint (it is usually best to begin furthest from your access route), take some of the mix on your trowel and tip it carefully into the joint, the correct amount of mortar for each joint will vary according to how deep, long and wide the joints are, but as a rule of thumb the joint should be slightly heaped (if your mix is too wet at this point it may stain the paving). Now pack down the mortar with a jointing tool (bucket handle), you must make sure that you have pushed the mortar right down into the joint, if you find this difficult, use a small piece of wood with an edge no more than the width of your joint to tamp down the joint before you strike it with your pointing tool. Finish the surface (striking) of the joint with a firm but gentle and smooth stroke of the pointing tool (if your mortar is too dry this may take a few passes).




Laying guide

 

  • FULL BED The bed of a slab is the mortar upon which it is laid. A full bed is complete 100% coverage of the area below the slab, the mortar is placed down onto the foundation in an area no smaller than the size of the slab and a fraction higher than the bedding needs to be, the slab is then laid on top and knocked down into position with a rubber mallet to the correct height, excess mortar will squeeze out from the edges and so 100% coverage of the slab base is made, this method produces the highest standard, but takes a lot of practise to get used to placing the right quantity of mortar, if you find you have too much mortar under the slab, DON'T try to bash the slab down to the right level, you may well break it. Lift the slab up and remove some of the mortar, then try again.
  • 5 SPOT It is a common error to understand that the 5 spot technique is a method whereby you place 5 spots (1 at each corner and 1 in the centre), then lay the slab to leave gaps between the spots. This is incorrect and may lead to a hollow thudding sound when the slabs are walked on and leaves weak, unsupported areas under the slabs. The correct way to lay using the five spot technique is to put enough mortar under the slab so that when the slab is tamped down the mortar spreads out and fills aprrox 90 - 100 % of the bed below. This method makes it easier to tamp down the slabs and you are less likely to place too much mortar, however you do have to be extra careful not to place too little mortar, small gaps are fine but large ones may lead to problems.



Mortar

 

  • Either Sharp sand or Soft (building sand) can be used for the mortar bedding of the slabs, Sharp sand is stronger than soft sand, but it's harder to work with, if the paving is only for pedestrian use and not for vehicles, then soft sand will be adequately strong.
  • PLASTICISER and ad mixtures - a range of products (ad mixtures) can be added to your mixing to make it more pliable, slow drying, speed up drying, resist frost etc, talk to your supplier about a suitable product, we would certainly recomend the use of plasticiser which slows drying time (allowing you more time to work) and improves the plasticity which makes mortar easier to work with and reduces the amount of water required in the mix.
  • JOINTS - Three typical types of joints are commonly used in paving
  • POINTED A mortar filled joint, struck with a convex pointing tool to leave a concave finish to the joint, strong, weed proof, decorative.
  • BUTT Slabs are laid pushed up against each other (not suitable for all slabs), best for utility areas where a decorative finish is not so important, strong, fast, cheap, not weed proof.
  • GRAVEL Gravel can be used to fill gaps between the joints, decorative but can be messy if the gravel gets knocked out, not weed proof, weak, better drainage - best for paving designed for decorative use eg as pot standing or to grow creeping plants between the slabs, not very good for frequently used surfaces especially when tables or chairs are required.



Pointing notes

 

  • Avoid hot sunny days and damp wet days and freezing temperatures - they can all be disastrous for pointing.
  • Allow plenty of time for pointing, it is a long job - but will add a fantastic finish to your patio, so worth taking time to do it right.
  • A top tip to speed up pointing is to ensure that you leave no excessively deep joints between the slabs when laying, ideally each joint should be partially filled leaving around 1.5 - 2cm depth
  • If your pointed joints are cracking after being filled it means that the mix is drying too fast, quickly dampen the joints with a very gentle mist spray from a hose, ensure you dampen both the slab and joint and don't put so much water that it is running or you may wash out the joints, after dampening re-strike the joints to bind the cracks you may need to repeat this process, covering the joints will help to slow the drying process.
  • Granular pointing products are available that can be swept into the joints of the patio and struck, these products are faster to use than traditional hand pointing because they are pre mixed, but they are relatively expensive.



Tool List

 

  • Wheel Barrow
  • Mixer
  • Vibrating Plate
  • Spade
  • Measuring jug or old mug
  • Rubber mallet
  • Spirit level
  • Tape measure
  • Bucket
  • Trowel
  • Jointing tool (bucket handle)
  • Pegs
  • Marking tools (e.g. string, paint, sand)



Material List

 

  • Paving
  • Sand
  • Cement
  • Plasticiser
  • Water
  • Mot type 1
  • Waste disposal for the diggings (e.g. a skip)