Concrete: same name but different

Concrete is a core material in building and forms the bare bones of structures in modern cities. Not a lot of people give it thought until the time comes to use it, whether it be for renovating or starting a new project. There’s more to concrete than what you see on the surface.

But isn’t concrete the same anywhere?

Absolutely not. While concrete can withstand massive amounts of pressure (especially when poured over mesh) there are different types for different jobs. To start with, concrete mixes come with different load bearing capacities.

What load bearing capacities?

The amount of pressure put on concrete slabs varies by what area it’s used in. 2500 to 3000 psi types are favoured for interiors and pathways. But for more durability, builders favour 3500 psi concrete mixes. Using up to 5000 psi blends in a home is rare. This type is reserved for industrial areas like warehouses and places where there’s heavy foot and vehicle traffic.

Concrete in general, when combined with steel mesh, is resistant to cracks and high pressure when the right type is used. When you meet with the contractor, they’ll know what material is better suited for the job you want to do.

What if I want something different, like colours?

Concrete doesn’t have to be boring! The concept of colour with concrete is nothing new. Clients can special order the product through their contractor so that it will suit the tone of their home.

The building industry has been making steps to project a “high class” image. One example is Austral teaming up with Camilla Franks, the kaftan designer. They introduced a line of vividly coloured bricks to use for interior spaces.

When someone says “concrete” a boring, grey slab of stone comes to mind. However, there’s much more to it than appearances. Concrete is formulated to take on different amounts of pressure and clients can order it coloured if they want something that will add character to their project.

What to know about reinforcement mesh

Steel mesh is an essential component of a sturdy build and few people besides those working in trades knows what is does. That is, unless you watch one of the dozens of renovation shows on television. Here are some basics about this material you should know if you’re looking to renovate or get into the building industry.

What is it?
An image associated with “mesh” is typically a fly screen or sliding door leading to a patio. Reinforcement mesh is different. The mesh is made of steel bars welded together to make a square or rectangular pattern.

What does it do?
Reinforcement mesh is an extra measure used to strengthen foundations. It’s laid out before the concrete is poured. The bars of the mesh are never smooth; there are grooves to “catch” the concrete. These two together make a near-unbreakable slab that’s resistant to cracks.

Is there only one type?
Absolutely not. Materials are custom ordered from major suppliers every day and there are many varieties on top of that. For simplicity’s sake, we have listed the three most common here.

  • Square mesh
    The all-rounder material. This type is used for flat concrete projects, like pathways, floor slabs and driveways.
  • Rectangular mesh
    This mesh is used for project where strength is needed in a certain direction. Like square mesh, it’s also used for footpaths and concrete slabs. However, rectangular mesh is required for walls and some foundation lays.
  • Trench mesh
    When you’re building from the ground up, you put the trench mesh in. This type is used for foundation support in homes and industrial spaces.

Steel mesh makes up the bones of any concrete structure. There are different types for different projects, whether it be square of custom made. This material reinforces concrete so that it can take hundreds of thousands of kilograms of pressure before cracks appear.

Photo credit: Rob de Vries, via / CC BY

How to Lay Concrete Like A Pro

Looking to do some DIY concreting? Creating a good concrete slab is not that difficult to do. Once you know how, you’ll be able to create great floors for your garden, patio or shed.

But first things first – materials. Get hold of some pre-mixed concrete, steel pegs, reinforced mesh and formwork (the mold into which your concrete will be poured). Talk to us for advice on materials and your project.

You’ll also need measuring tape, a spirit level, shovel, concrete edger and rake, float, levelling screed and stringline.

Once you have everything ready, these are the steps to follow to create a pro-looking concrete floor.

  1. Dig out a level to match your formwork. It should be at least 100mm deep. Dig the area that you wish to place the formwork in and add an extra 50mm in thickness for the formwork. Make sure all of your measurements are square and that your ground is even by using a spirit level.
  2. Secure your formwork using steel pegs. Make sure they’re firmly hammered into the ground.
  3. Lay down some reinforced steel meshing. This stops your concrete from cracking over time. Make sure you have at least 25mm of concrete covering the mesh.
  4. Even out your concrete. Use a rake and screed to spread the concrete evenly and flatly. Tap the outside of the boxing with a hammer or use a concrete vibrator inside the boxing to eliminate porous finish once boxing is removed.
  5. Smooth the surface. Use a steel trowel and wooden float to create a smooth surface and your concrete edger to add a nice finish.
  6. Take away your formwork. Remove the formwork after 3 days to reveal a perfectly constructed concrete slab.

For more information and advice, contact us today.

How to Stop Your Concrete From Cracking

From faces or floors, one thing most humans can’t stand is cracking. So what can you do to keep a clear, youthful looking footpath?

Avoid gaps

Wood, rubbish, tree roots, ants and other subterranean creatures can create gaps in the soil which cause cracking as your concrete expands and contracts. Carefully prepare your ground with compactors and the appropriate use of water.

Reinforce. Reinforce. Reinforce.

Reinforce your concrete. This strengthens it and prevents small cracks from widening. Also use expansion filler in between walls and other areas where your concrete won’t have the space to expand into.

Make the first move.

Don’t wait for nature to crack your concrete arbitrarily. Place control joints using saw cutting to create a weak point for your concrete to crack. These joints should be up to 3 meters apart and placed on corners.

While cracking can be unsightly and difficult to avoid, following the above steps will help you greatly reduce it.

Is All Concrete The Same?

If you’re new to concrete, it’s tempting to think of it as being all pretty much the same. However, this is not the case.

Much like wine, there’s a concrete type for every occasion.

Old school concrete

Concrete has an ancient history. The Romans made it from hydrated lime and volcanic ash and clay (in the case of hydraulic concrete). This helped them create some of their most enduring monuments and their concrete was the envy of the ancient world.

Regular concrete

Modern concrete is usually a combination of cement, sand, stone and water. The sand is often mortar or brick and materials such as leaves and twigs are washed and filtered out to ensure it is as strong as possible. The exact mix varies depending on how the concrete is to be used. Regular concrete can withstand pressure from 1450psi to 5800 psi and concrete that is to be used for structural purposes will be made to withstand higher pressures than that used for more cosmetic purposes or as a barrier, such as blinding concrete (used on the floor of a building to prevent dirt and mud entering the structure).

High strength concrete

High strength concrete can withstand over 5800psi and uses less water in its mix than regular concrete. It also uses a carefully selected aggregate to ensure it can withstand high loads. Some types of high strength concrete are also designed to be elastic.

Stamped concrete

Stamped concrete is used by architects and is created so that it can be textured and coloured to resemble stone, bricks, wood or other attractive designs. You’ll often find it in car parks and on walkways as it’s very resistant to wear.

High performance concrete

High performance concrete is built to excel in a range of specific areas (not necessarily strength, as in the case of high strength concrete). These other areas include durability in severe conditions, environmental quality, ease of application, permeability and density.
Research into concrete is uncovering many new forms, which we’ll look at in a future article. The above types however are the standard forms of concrete in use today.