How To Landscaping - Mixing Mortar





Mortar can be mixed to many specifications for varied applications



Sharp Sand mortar

 

  • Strong compressive strength.
  • Not very sticky or pliable making it harder to work with.
  • Generally used for high weight carrying paved areas.
 

Soft (building) sand mortar

 

  • Has a good workable texture and sticks to the working material well.
  • Can be struck to give a smooth finish for pointing.
  • Generally used for brick laying, pedestrian paving and for pointing.
 

Sharp & Soft sand mixture

 
  • Combining the qualities of both sands, this mixture is often used for screeds and rendering.



Ingredients

 

  • Cement is added to sand to bind the grains together, it doesn't make the mix stronger, it is simply a binding agent. the quantity of cement required varies depending on the use of the mortar.
  • Water should be added to all mixes to aid the chemical processes and to achieve workability in the texture of the sand. The Quantity of water added will vary depending on the type of mix, its intended purpose and the dryness of the sand being used.
  • Additives - There are many additives available on the market, they are added to the mixture to provide special properties to the drying mortar such as frost protection, fast drying, slow drying, Colour. The most commonly used additive is plasticiser.
  • Plasticiser is a very common (and recommended) additive which reduces the amount of water required in a mix, increases drying times (allowing for a longer working period with each mix), and increases pliability (workability) of a mortar.
 

Rough guide to Cement in Mortar mixing

 

- check the manufacturers guide to be certain.

  • Mortar for brick laying - 1 cement to 6 sand (1:6)
  • Mortar for paving - 1 cement to 5 sand (1:5)
  • Mortar for pointing - 1 cement to 4 sand (1:4)
 
 

Rough guide to Water in Mortar

 

- check the manufacturers guide to be certain.
  • Sharp sand mortar - Sharp sand is not very absorbent and so uses relatively less water than a soft sand mix, add water to make the mix "wet" but not runny, if the mix is runny, add more sand and cement, the mortar should be able to hold its own weight without slumping when placed on the ground .
  • Soft sand mortar - Soft sand has a higher water holding capacity than sharp sand and so requires more water to reach workability, aim for a mix that can hold its own weight, Soft sand mixes will look creamy in texture when they are just right for slab and brick laying.
  • Pointing Mix - Hand applied pointing mixes only require a small amount of water, they should have enough moisture to begin binding in small clumps but still retain a slightly crumbly texture.



Mixing Methods

 

By hand 

 

  • Mixing by hand is hard work, but a good option if you'll only be using a small amount of mortar.
  • You can mix in either a wheel barrow or on a board / smooth concrete etc (the mix will stain so keep away from anything that mustn't be spoiled).
  1. Start by adding half your sand, if you are making a 1:4 mix then add 2 sand (half of 4).
  2. Now add all the cement required, in this case 1.
  3. Next add the remainder of the sand (2).
  4. Using a clean spade mix the dry ingredients together.
  5. Once the ingredients have a consistent colour use your spade to form a central hole (reservoir).
  6. Pour some water (mixed with additives if required) into this central hole, too little water is better than too much, once you've had some practice you'll be able to add most of the water you need in one go, but for now just pour in a small amount.
  7. Mix the ingredients with the water.
  8. If you have a nice smooth texture then your all done and ready to go.
  9. If the mix is still dry you'll need to repeat the reservoir / adding water step.
  10. If the mix is very sloppy, you'll need to add more sand & cement in the correct proportions to find the correct consistency.

 

By mixer

 

  • Mixing with a mixer is quicker and easier, but it can be messy, make sure you're protecting any areas you don't want spoiled with a mixing sheet, tarpaulin etc.
  1. Start with water (mixed with additives if required), once you're practised at mixing you can add all the required water at this stage, however for now just add around a quarter of a bucket to the mixer, keep an eye on the wetness of the mix at every stage and keep adding water to keep the mix wet but not sloppy.
  2. Now turn on the mixer.
  3. Using a spade scoop half your sand into the mixer (be careful not to put your spade inside, if it catches the mixer you may hurt yourself).
  4. Now add all the cement for the mix.
  5. Add the remaining sand.
  6. Adjust water, sand, cement quantities to the desired consistency.
  7. Pour the mix from the mixer into a wheel barrow.
  8. You should now have a good idea of how much water you need for a mix, add this amount to the mixer.
  9. Add all the sand for a mix to the mixer.
  10. You now have a mixer full of water and sand, this is called an empty mix and will help to keep your mixer clean, leave the mixer running (unless you're leaving it for a long time) and you'll simply need to add cement to finish the next mix.
  11. Repeat the empty mix every time you mix up.

 

Cleaning the mixer

 

  • When you come to the last mix of the day, use just half the sand & water you'd normally use, once this has spun for a minute or so, pour out the mix and either save it for the next days mix or discard it.
  • Now pour half a bucket of water into the mixer and allow this to mix for a minute or two, turn off the mixer and pour the water back into a bucket and either save it for the next days mix or discard it.
  • Leaving the mixer turned off you can scoop out the remaining sand, mortar to clean the inside of the drum.
  • WARNING - hire companies don't like their mixers returned covered in dry mortar or concrete, it is difficult to remove and may damage the mixer, they'll probably charge you a cleaning fee.