Concrete forming basics

Concrete forming basics


Are you planning on pouring but need to learn more about building forms? Or maybe you want to know more about the subject?

Concrete forms are essential when doing pours; you’re left with nothing without them. The formwork is the mold for concrete and creates the shape of the concrete using a series of wood, composites, or steel forms.

Formwork not only holds the shape of the concrete as it dries; it also bears the weight of the pressing concrete. That’s why it must be built strong to resist the weight of supporting structures. The weak form will result in tears and curses, so it had better be done well.

The basics of formwork begin with the blueprints. A simple sidewalk requires the least of drawings and thus the least of formwork and materials. A complex two-story stem wall requires multiple pours and deep footers. That’s why it requires a complex blueprint and a complex set of forms with various materials.

Know your limits when doing concrete work basics. Remember, you can only pour concrete once, as it has its own working time. Once it starts the curing process and hardens, it will be tough to remake it.

With that disclaimer in mind, essential footings that adjoin the house are best left to the professionals. Any slab that bears weight or is on sloping land will have a footer.

How to build wood concrete forms

Slabs like a detached or abutting patio, sidewalks, and driveways all need no footer. The average homeowner can do them. Simple sidewalks and driveways need no excavation (except for grass and surface roots). Learning how to build wood concrete forms will help you in many home projects, such as making concrete countertops.

Concrete forming supplies

Forms made from pressure-treated 1x4s, or plywood, are placed on the ground’s surface and held with stakes. Making your stakes is easy and can be done by ripping a 2×4 precut stud in half with a circular saw.

Cut four 45 (or 52 if your saw has it) degree angles using a miter saw one end of each half of the ripped boards. Then, cut the other end square to length as needed into thirds or halves.

Long runs of 1×4 stock are easy to bend and curve to the landscape as needed for driveways and sidewalks. At the same time, they are using 2x4s, which work best for rigid straight lines on rectangular and square slabs. Tighter curves require different materials. 1×4 pieces of a hardy plank or other cementitious siding boards flex quite a bit when bent at radiuses and arcs. Scoring the back of the form with vertical lines will help increase the bend into an even tighter radius.

How to easily transport concrete

Estimating the concrete amount needed

Concrete work, from a hobbyist perspective, can be a complex process, even if it’s just a small amount to pour. That’s why the average homeowner needs to learn the basics of each concrete process from beginning to end. This will ensure that everything comes out right the first time. You don’t want to be short of concrete on your big day.

The first step is to use the blueprint or drawing of the actual dimensions of the slab. These dimensions are the slab’s length, width, and height or thickness (add ¼” for waste). Now multiply these dimensions, and you get the square footage amounts. To get the concrete yardage, divide the answer by 27, and you get the correct amount of concrete needed for your slab.

Odd shapes can sometimes throw a loop into the mix when estimating concrete. Where diagonal lines meet perpendicular lines, confusion can ensue. A driveway apron where it meets the road is a prime example. Calculate the average distance between the sloping area’s most significant and minor measurements.

For example, if a driveway measured 20 feet wide at the road and 16 feet the rest of the way up the driveway, the mean measurement would be 18 feet wide for the diagonal section that abutted the roadway and 16 feet for the remaining driveway.

They best break concrete slabs into square and rectangular sections when estimating complex-shaped slabs. This is especially true for footers. Footers will also need to have rebar calculated into the picture.

Add the width and length of the slab to find the area and multiply it by two. The sum is the number of square feet you need for rebar. It must be divided by 20 since rebar comes in 20-foot-long sections.

Depending upon the size of your concrete pour, you should use bags or a ready-mix delivery service. The basic rule of thumb is that a ready-mix will only bring out a truck if the delivery size is within 50 miles of their yard. Also, it needs more than three yards, and adequate access is available for the car to deliver the mix. A concrete pump can be rented for hard-to-access areas.

Getting bags will be your best bet if you have less than three yards of concrete. When your pour is close to three yards, rent a concrete mixer to mix all the bags. It will help in completing the pour in a fluid motion. Bag amounts come in 40, 60, and 80-pound sizes.

The best way to work with the mixer is to have a dedicated mixing spot with the mixer, water, and bags available. That way, you can leave the mixer rolling with water and ready to mix concrete in it while you empty your bucket/wheelbarrow in the forms.


Understanding the basic principles of concrete forming is essential to ensure that your project achieves optimal results. While small-scale wooden concrete forms are relatively easy to construct, larger projects require more advanced mathematical calculations.

For those looking for alternative options, Insulated Concrete Forms may be a viable solution. These forms are made using insulation material and are designed to remain in place after the concrete sets, although they are more expensive than traditional wooden forms.

One of the key benefits of using Insulated Concrete Forms is that they can improve the heating efficiency of the building. This guide provides a comprehensive overview of the process and is particularly useful for those looking to construct small concrete slabs.