What Materials Do I Need?
When plastering walls and laying bricks, there are a number of products needed that make up the raw materials vital to the success of your project. These are:
- PPC SUREBUILD Cement 42,5 N which is ideal for mortar and plaster and complies with SANS 50197. PPC SUREBUILD Cement 42,5 N with extra strength which makes more concrete than regular 32,5 general purpose cements*
- Plaster Sand - ask your supplier for clean plaster sand. The sand should be free of twigs roots or other foreign matter
- Building Sand (for bricklaying) - remove any twigs, roots or foreign matter
- Clean water - if you can drink it, it is suitable for building
*For more details on comparative mixes, see the PPC Affordable Housing page.
How to Mix Mortar & Plaster
- Remove any lumps, stones or foreign objects from the sand.
- Measure out the sand and place it in a long thin heap on a flat, clean, hard surface (or mix in a wheelbarrow if making a small batch).
- Pour PPC SUREBUILD Cement 42,5 N on top of the sand.
- Mix PPC SUREBUILD Cement 42,5 N and sand together until uniform in colour.
- Create a hollow in the centre and slowly add clean water while mixing. The mix is correct when it has the consistency of a thick paste, able to stand by itself without collapsing, yet wet enough to be spread easily with a trowel.
IMPORTANT: Mix only as much mortar or plaster as you can use in 2 hours. Should your mix stiffen slightly in this period, some water may be added to regain workability. After 2 hours the unused mortar or plaster should be discarded.
How to Lay Bricks
- Bricks must be laid on a concrete slab or foundation.
- Start by building the corners. To lay the first course of bricks, use your trowel to spread mortar onto the concrete surface. Use a fishing line stretched tight between the corners to lay the first row of bricks. The back top edge of every brick laid must be exactly in line with the fishing line.
- Place enough mortar to lay 2-3 bricks at a time.
- 'Butter' each new brick by applying mortar onto the end of the brick before placing it hard up against the preceding brick and into the mortar bed.
- Tap it into place until the top edge of the brick lines up exactly with the fishing line guide.
- Scrape away any excess mortar that has been squeezed from between the bricks as you go before it dries and hardens. Ensure that you remove the mortar before it hardens.
- Use a spirit level to check that the row is level and to ensure that the corners are vertical (i.e. straight up and not leaning in or out).
- Once the corners are built, simply move the fishing line up, row by row, and fill in the spaces between the corners. Because your bottom row is level and your corners are vertical, your whole wall is sure to be level and vertical.
How to Plaster
- When plastering walls, try to avoid working in the direct sun or drying winds. Plaster needs to retain its moisture for as long as possible.
- Load your hawk with plaster mix and scoop it onto the steel trowel. Apply to the wall with pressure.
- Plaster small areas at a time. A whole wall should be completed in one operation.
- Once the plaster starts to stiffen, level the surface by pulling a straight edge over the plaster with a sawing motion.
- Wet the levelled plaster with water (flicked lightly with a brush), then use a float to smooth the surface.
- Cover the plaster area with plastic or use a fine spray of water to keep it damp for as long as possible (up to 7 days).
Tips for Using Concrete in an Environmentally Responsible Manner:
- Use the recommended mix design proportions on the bag to mix the concrete
- Use the correct strength mix to minimise waste
- Do not add too much water – this will reduce the concrete strength
- Mix just enough concrete (mortar or plaster) for your project
- If you are building a house, make sure you design for optimal energy efficiency
- Use good quality aggregates and potable water
- Cure the concrete properly to get maximum durability
- Do not waste water when cleaning
- Dispose of your paper bags in a responsible manner
- Use local raw materials - this reduces the carbon footprint of the transport component
- Recycle building rubble where possible
For more advice on cement, plastering walls and how to lay bricks, ask your PPC Cement stockist or call the PPC toll-free help line: 0800 CEMENT (236 368)
Click here for this information in downloadable PDF format.