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Five Rules for Perfectly Clean Results

Five (5) rules for Bricklayers, “IN ORDER OF IMPORTANCE”, that will help prevent mortar and brick damage when cleaning

ALL BRICKS MUST BE LAID CLEAN. Especially concrete blocks, concrete & dry pressed bricks.

  • Pointing must be cut and then dry brushed when the mortar is crisp so that all four edges of the bricks are clearly visible and clean.

These edges must be sharp & clearly visible without any traces of mortar on them.

  • Remove all mortar from the brick face (especially the Perpend) by cutting and dry brushing.

​​               – N.B. Only milky mortar smear should be left on the brick or block face.

Then use a damp sponge for a perfect finish. DO NOT USE A WET SPONGE.

Use the 9:2:1 AS 3700 M2 mix. 9 Sand : 2 Lime: 1 Cement

  • This is the M2 mix recommended for houses by AS 3700
  • ​Fatty sands may require slightly less lime to remain workable. Adjust as required.
  • Make sure the mix is consistent – use buckets or calibrate with buckets.

Buckets are best. The standard practice of using a number of shovels of sand to one bag of cement makes –                     inconsistent mixes. Melbourne mortars are mixed too hard and they can vary from being too hard through    to being too soft on the same house.

No plasticiser chemicals – Use lime instead!

  • Lime is the traditional plasticiser of choice. It is a carbonate and is readily cleanable with acids.
  • All Brick Cleaners have problems with plasticized mortars – for many reasons – see below.
  • If plasticisers must be used then lay the bricks EXTREMELY clean (see 1 above) and tests should be done to prove that the mortar will be cleanable without damaging it or the bricks.

Remove all scaffold splatter from the bricks and all mortar droppings on the wall & the slab.

Always cover top course in wet weather to stop bricks from staining.

​N.B. Plasticisers and lime replacements change mortar and make it harder to clean as they : ​

Make mortar lighter, harder and more brittle by making small bubbles​ in the mortar and this reduces the water content up to 30-40%

They coat the mortar with a waterproof layer that prevents acids from working.

They contract, tighten and harden mortar much faster making it impervious to acid cleaning

They have a glue that makes mortar stick much tighter to the bricks which acids cannot clean.

Chemical plasticisers do not react with acid and make sticky extremely hard mortar.

Our field tests and experience have proved even if you only use 1/4 of the recommended amount of Plasticizer  it will make bricks (and tools) uncleanable.

Plasticized mortars with Lime added seem to react and become far too hard

Plasticisers added to the premix water will conflict with lime and the combination will make a sticky unworkable and unusable mix in the mixer.

We recommend considering the following points if you want to use plasticizers:

  • ​Only use them if there is no alternative
  • Plasticisers and Lime seem to conflict in the mixer and become too hard when curing
  • Plasticizers when added first compete and inhibit lime from mixing and working as it should.

Consider adding plasticised water at the end if you have to add them at all.

Final Caution. You may fail the mortar tests if you use plasticizers or lime replacement chemicals:

Plasticizers and Lime replacements are chemicals that are used to replace or reduce lime, and they will reduce the amount of calcium oxide (CaO) in the mortar which is a measure of limestone or (CaCO3). This may lead to mortar test failures as Builders test for CaO to check if the mortar passes the mortar test. If it fails they may back charge the brick layer for the repointing costs.