How Does concrete and formwork Work?

The cornerstone of any successful construction project, concrete formwork ensures structural, safety and security at almost every stage of the operation.

Whatever the size or scope of your Perth building project, investing in solid formwork is important for many reasons—and we’re going to tell you why.

But first, here’s a practical explanation of concrete formwork.

If you want to learn more about concreting options, check out our resources:

1. What Are The Most Common Concrete Types?

2. How to Find the Best Concrete Contractor in Melbourne

3. Top Benefits of Hiring Professional Concrete Services

4. 5 Ways You Can Use Concrete in Your Garden

5. What Concrete Extension Types Can You Add To Your Home?

6. How To Remove Stains From Concrete

Concrete formwork explained

Formwork is structural and is the term used for specialised concrete construction moulds. Wet concrete is poured into these supportive moulds, which are usually temporary, to set and take form until it can support itself.

The concrete formwork process is often referred to as shuttering, which is typically made from timber—although some contractors use reinforced plastic, steel or fiberglass.

Often, once the concrete structure has set and deemed safe, the formwork is safely removed from site.

The importance of formwork

Any aspect of a construction project that offers support and structural safety is essential—formwork is no exception.

Not only does the right kind of formwork improve site safety and provide vital support to certain elements of a building’s design in those vital early stages, but these ancillary structures also ensure the smooth running of a construction project while increasing the overall quality of the finished structure.

Here are the key qualities of good formwork:

• Can withstand both live and dead tools.

• Will help to achieve your preferred concrete shape and finish.

• Sets complete accurately in along your desired line.

• Is easy to remove without damage and is as lightweight as possible.

• Won’t warp or lose form when exposed to extreme external elements like heat and can reset, with ease, on a firm base.

• Is constructed to meet your specific project needs and requirements.

As we said, the formwork can make the difference between building success and failure. Without formwork, you run the risk of running into no end of struggles or calamities during the concreting phase of your construction project.

At Concept Concrete, we’re experts in formwork and we can create structures in timber & plywood as well as steel and specialised plastic.

With years of specialist formwork experience and a longstanding local track record of success, we can provide formwork that’s tailored to your specific needs or goals, down to the very last detail.

So, if you’re looking for a robust, reliable formwork expert for your next Perth construction project, we can help. We’ll be happy to guide you through the process and advise you on the type of shuttering that will work best for your needs.

Once you’re happy with the specs and quote, our formwork experts will come on-site and take care of everything for you.

Interested? Contact us and we’ll be happy to help you with all of your Perth formwork or concreting requirements. We look forward to working with you.

And How They Help In Concrete Construction

Whether you’re building a concrete patio or a skyscraper, you’re going to need concrete forms to get the job done. Without concrete forms, your concrete won’t hold its shape and will be at risk of cracking and losing its strength. Concrete forms go hand-in-hand with other concrete placing techniques to ensure your concrete remains strong and durable. So to guarantee your concrete construction projects go smoothly, order enough concrete products for the job and make sure you use concrete forms.

Keep on reading and learn how to use formwork, the principles behind it, and why it is so helpful on the job site.

What Is Concrete Formwork?

Formwork, also known as concrete forms, is a temporary or permanent mould used to create concrete slabs and structures. It’s a barrier that holds the fresh concrete in place and helps with shaping the concrete until the concrete is strong enough to hold its own weight and shape.

To work effectively at supporting the concrete’s weight and shape, concrete forms must:

• Have tight joints so the wet concrete cannot leak through;
• Be rigid enough to prevent bowing under the weight of the concrete;
• Be strong enough to hold the concrete in place;
• Have proper horizontal and vertical support and bracing, such as with poles and stabilizers (also known as falsework);
• Be completely level; and,
• Be able to withstand the elements without warping.

How Is Formwork Made?

Formwork is usually made from timber and plywood. But it can also be made from other materials, such as metals, ceramic, or glass fibre reinforced plastics.

Plywood formwork is also called shuttering. Shuttering is the most popular type of formwork and is created on-site using water-resistant plywood and timber.

When on the job site, concrete contractors will erect plywood, steel, or aluminium formwork to create the moulds of concrete slabs, walls, and other structures.

Concrete formwork includes the following components:

Formwork Sheeting

The formwork that comes in direct contact with concrete is called the formwork sheeting, or the formwork shell. This sheeting will mould the shape of the concrete and have the most influence on the finished concrete surface.

Formwork Bearers

The formwork bearers, which are usually made of timber or steel beams and clamps, support the formwork sheeting. These distribute the concrete forces through the falsework, supporting structures, formwork ties, and soil.

Formwork Ties

Formwork ties are usually made of steel wire and are used to tie two formwork faces together to support horizontal pressure from vertical formwork.

The steel wire is slung around the formwork bearers, guided through boreholes in the formwork sheeting, and tightened by twisting the wire.

Once the formwork is constructed, concrete contractors will place rebar inside the formwork to reinforce the concrete.

Next, contractors will pour concrete inside the forms. Once the concrete hardens, they will remove (strip) the forms from the concrete structure if using temporary formwork.

To prevent damage to the concrete and difficulties when removing formwork, it’s important to consider the placement of formwork and the sequence in which the framework will be stripped.

Avoid using too many nails and supports (falsework) when building formwork, as this will be too difficult to strip later on. Only use as much as necessary to maintain the support of the formwork.

How Long Do You Leave Forms On Concrete?

Temporary concrete forms should be left to support the concrete until the concrete has thoroughly dried and reached an ideal strength to support its shape. This usually takes about two days after pouring the concrete.

If you remove the formwork too soon, the concrete might begin to sag, crack, and collapse. Remember to be patient and let your concrete thoroughly dry before removing formwork.

What Is Formwork Used For?

Formwork is used for holding the shape of concrete while it dries. It is commonly used for building concrete for:

• Foundations
• Walls
• Ceilings
• Beams
• Columns
• Paths
• Walkways
• Sidewalks
• Driveways
• Patios

The type of formwork you use will depend on your project needs. A simple temporary plywood formwork, such as plank shuttering, is suitable for moulding concrete paths and driveways.

But if you’re building a concrete foundation for a home, you will want to use more sophisticated formwork, such as permanent insulated concrete forms.

What Are Insulated Concrete Forms (ICF)?

Unlike traditional concrete forms, insulating concrete forms (ICF) are not removed once the concrete hardens. Instead, ICFs remain as permanent parts of the concrete structure.

While concrete creates the structure, the ICFs insulate the structure. Homes and buildings with ICF foundations are soundproof, airtight, and comfortable in all seasons. This insulation helps homeowners save on energy costs for heating and cooling throughout the year.

ICFs are often made from a combination of insulating materials, such as plastic foam beads and cement, or wood fibre and cement.

Another popular material for ICFs is expanded or extruded polystyrene. Expanded polystyrene is made by expanding plastic beads in a mould, similar to Styrofoam coffee cups.

Extruded polystyrene is made by expanding plastic resin and extruding through a die, similar to meat trays from grocery stores.

ICFs typically come in blocks or planks. ICF block systems are pre-formed with foam and metal or plastic ties. They are ready to stack and interlock when they arrive on site.

Plank ICFs are individual panels or planks of foam requiring assembly on site with ties.

Block ICFs save you time and labour costs, while plank ICFs save on shipping costs since they are more compact to ship.

These concrete forms usually provide at least two inches of insulation on both sides of a concrete wall.

ICFs are not only faster to place, but they also provide significantly better insulation compared to wood or steel frames. So if you’re planning to build a new home, consider using ICFs for a well-insulated foundation.

When to Use Formwork

Formwork is necessary when there is no soil or other structural components to support freshly poured concrete and hold it in the desired shape.

Formwork is necessary for the construction of concrete and reinforced concrete structures, such as:

• Solid structures—e.g. foundations and columns
• Reconstruction of structures
• Structures with special functions—e.g. chimneys and containers
• Bridges and towers
• Public buildings
• Structures with an irregular arrangement

Formwork

Vertical formwork is necessary for building concrete foundations, walls, and columns. Tie wires or tie rods are also used with this formwork to support the lateral pressure of concrete.

Vertical formwork must also be anchored to the subsoil to prevent lifting from buoyant forces in the concrete.

Horizontal Formwork

Horizontal formwork is necessary for constructing concrete ceilings and beams. This formwork must be supported against vertical and horizontal loads, using formwork load-bearers and columns, braces and struts, or a rigid connection to existing structures, such as walls and columns.

Concrete forms are an essential part of building sound concrete structures. When constructed correctly, formwork moulds concrete into the desired shape and supports the weight of concrete while it’s drying.

And most importantly, concrete forms allow concrete to reach its optimal strength and durability without sagging or cracking.

Engineered Formwork System

Unlike traditional formwork, engineered formwork is made of metal. They are prefabricated, not built on-site as the conventional ones. Engineered formwork consists of steel or aluminium, and since it is prefabricated using a more durable material, this option is often more cost-efficient and can be reused – up to 3 000 times! It is also more durable and reliable since a change in environment or temperature will not change its performance. Since you don’t have to spend time on setting up like the conventional ones, it makes the whole process faster, too.

Conclusion

It is clear that concrete forms are necessary for ensuring the concrete setting properly during a construction project, whatever the size of it. Even though timber is usually used for maintaining the form of concrete, there are different materials and types of formwork that can be used. However, prefabricated formwork is more useful for contractors, but you can easily sell them after finishing the project. A.L. Blair can help you with any project you have in mind, so don’t hesitate to reach out.