Concrete forms are useful when it comes to construction projects, but they are unsightly. It is easy to see why many people want to remove them as soon as possible.
However, if you want your concrete project to last a long time, it needs to be correctly mixed, poured, and left to cure for the appropriate length of time. Typically, forms can be removed after 24-48 hours, although it depends on the grade, type, and temperature of the concrete.
Concrete must be mixed and poured properly, or it may not cure correctly. Unfortunately, many find this out the hard way by making one of the following mistakes:
- The mixture is too dry – when concrete is too dry after mixing, it may crumble easily, and the final product will be weaker.
- The mixture is too wet – concrete shrinks as it dries, and when it is too wet it shrinks more than it should. This can cause cracking and makes for less durable concrete.
- Concrete poured too thin – Concrete needs to be 4–6 inches thick, or it will be at risk of cracking or breaking.
- Rely too much on reinforcing mesh – don’t depend on reinforcing mesh to pick up the slack if the concrete is not mixed correctly.
- Using cement that is too old – expired concrete will make a finished product that is too weak.
- Smoothing concrete too soon/too late – concrete needs to be smoothed, or troweled, at just the right time. If the concrete is too wet or too dry, it will be too difficult to trowel.
- Getting concrete on your skin – concrete-to-skin contact is not recommended and can cause bleeding and blistering.
- Removing the molds too soon – the concrete will not be able to hold its shape.
When Should You Remove Concrete Forms?
Concrete forms can be removed as soon as the concrete is cured. Removing the forms should only be done if the concrete has finished drying and is strong enough.
How long the curing process will take depends on several things, including the kind of concrete being used as well as the kind of form you are using. See the tables below for more information.
When to Remove Framework Based on Type
|Item #||Concrete Type||Time for Removal|
|1||Type 1||After 7 days|
|2||Type 2||After 10 days|
|3||Type 3||After 3 days|
|4||Type 4||After 14 days|
|5||Type 5||After 14 days|
|6||ATSM C 595, C 845, and C 1157||Times will vary|
Another thing to consider is what kind of support forms you are using. Different forms require different removal times.
When To Remove Framework Based on Forms Used
|Item #||Form Type||Time for Removal|
|1||Vertical forms (such as for walls, etc.)||24 hours|
|2||Soffit forms (slabs)||3-4 days|
|3||Soffit forms (beams)||1 week|
|4||Propping forms (slabs)||1 week|
|5||Propping forms (beams/walls)||2 weeks|
|6||Propping forms (arches)||3 weeks|
Common Form Removal Techniques
Form work removal must be done carefully, or it risks the integrity of the structure as well as the safety of everyone involved. Once you are sure the concrete is ready, it is time to strike off the forms. Here are some common techniques and for removing concrete forms:
- Make sure concrete is ready – check if the concrete is adequately hard and dry or use a wireless sensor. Slabs and beams particularly must be strong enough to take on loads.
- Starting from the top, begin removing the form carefully. A hammer can be used to remove nails holding the form together.
- Work on each side – it is best to alternate sides as you remove pieces of the form.
- Clean work forms for reuse or responsibly discard.
Voyaging into the world of concrete may have you asking some questions, especially if this is your first project. Read on to find answers to some of the most frequently asked questions.
What Is the Difference Between Concrete and Cement?
The terms cement and concrete are often used interchangeably, but they are different things. Cement is a binding mixture made from limestone and other things, and it is an ingredient of concrete. Concrete is made when cement is mixed with water and aggregate.
What Are Concrete Forms?
Concrete forms are solid objects, usually made from wood, that help concrete stay in place before as it dries.
What Is Curing?
Curing is the process where concrete is given enough air, moisture, and time to set and become stronger. Curing must be allowed to happen correctly if the concrete is going to last a long time.
How Long Does Curing Take?
For concrete to be cured to its full strength, it takes anywhere from 2 to 4 weeks.
When Can Most Forms Be Removed?
Times vary, but most concrete forms can be removed after 24–48 hours.
What Can Happen If Forms Are Removed Too Early?
There are several things that can happen if forms are removed too early. This can cause the concrete to slump, form cracks, or collapse.
Can the Forms Be Left Indefinitely?
Concrete work forms can be left up indefinitely. Most people do not like the way they look, and they can get in the way if you want to do further construction projects. However, it really comes down to personal preference.
Can the Weather Make a Difference?
Weather can cause a profound difference in how long it takes concrete to dry. If conditions are too cold, concrete can freeze. If it starts raining soon after pouring, it’s best to cover the concrete as it may not cure properly if it gets too wet.
How Do I Stay Safe While Working with Concrete?
It is important to take safety precautions while working with concrete. Wear proper personal protective equipment such as goggles and good quality water-proof gloves.
If any wet concrete gets on your skin, wash immediately with water and mild soap.
Concrete forms are used to make concrete stay in place while it is drying. Once the concrete has dried enough, the forms may be removed. It is important to allow enough time for the concrete to dry based on the concrete type and the forms being used.