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Sonotubes - Concrete Forming Tubes


What is Concrete Forming Tube ?

Concrete forming tube also called Sonotube is a structure made from a preformed casing with waxed paper or lamination. It is used to form cylindrical columns. These round structures are used for entryways, light posts, buildings, structural columns and many other applications. There are different types of sonotubes to fit each application. The choice will depend on design of the structure, building codes, soil characteristics and other job specifications. Your building contractor or supplier will be able to help in the selection of the right materials and design for the support system.

The only area where the use of these concrete forming tubes is limited is in standing water. The structures can only withstand water for about 24 hours. There are special forms that come with maximum strength that allows them to withstand wet conditions for 72 hours. In wet areas, the top should be covered so that the structure does not fill with water.

Two pieces of sonotube can be used together provided they have the same diameter. You just have to slit them vertically to fit together and then strap them above and below. You can either strap them or use sheet metal screws. Note that sonotubes are not fire rated since they are for temporary use only. They should be removed from the jobsite before the project is completed.

By using sonotube, you lessen the amount of concrete you use. And depending on the soil, you may not have to use any concrete. Sonotubes are readily available in the market from the local sonotube distributers.

What is a Sonotube used for?

Sonotubes are top quality, heavy-duty cardboard structures that hold concrete to create a column with a smooth surface. The tube must be sturdy enough to stand the pressure of concrete. It must have a smooth interior surface to ensure excellent column wall finish.

Generally, concrete columns can be used in a variety of applications. Sonotubes offer an affordable and efficient method of producing different sizes of concrete columns in terms of length and column diameter. Short and wide columns are often used as sturdy bases for parking lot lamps, street signals, streetlights, and deck posts. On the other hand, tall concrete columns are majorly used for external decoration, foundational support in basements, roof support around buildings, warehouses, and more.

Sonotubes are associated with incredible cost-efficiency and strength-to-weight ratio. Sound hobbyists and sound technicians use Sonotubes cut in half vertically to enhance acoustics in sanctuaries and auditoriums. They can also be used in the construction of sound cabinets because cardboard walls don’t absorb sound waves. That makes them an ideal material. The versatility of Sonotubes is among one of their many benefits. Though they’re not reusable, they don’t require extra exterior support as it is the case with steel and fiberglass.

Choosing the right sonotubes

The choice of the right material and design to support a given system for any structure depends on the overall design of the structure, local building codes, the soil characteristics of the project site, and other details. All these are highly technical aspects that must be analyzed by a licensed, experienced architect or engineer familiar with your construction project. Such an expert can offer precise answers and insights.

The maximum rate of pour

A standard wall sonotube (about 12 foot long) and a 20-foot long heavy wall commercial sonotube are designed to be filled in one lift with no restrictions on pour rate. However, to achieve the best results, it’s recommended to use multiple short lifts to equate vibration. Hire a technical assistant for concrete columns in excess of 20′.

Fire rating for sonotubes

Generally, Sonotubes are not fire rated. This is because their intended use is temporary, and single-use concrete forms should be removed from the job site upon successful project completion.

The Sonotube’s crush value

According to building professionals, Sonotubes aren’t created to carry structural loads. It is not recommended to use them for any application or reason other than their intended purpose unless you already understand the risks of doing so.

Can Sonotubes be used in water?

Though Sonotubes are created with patented water-resistant tech, they are not supposed to be exposed to stagnant water for a long period. Under these conditions, their performance isn’t guaranteed, but sometimes you can’t avoid placing them in water. In case groundwater seeps into the specific hole you plan to install a Sonotube or the soil appears to be saturated, it’s recommended to use Sonotube Commercial form, seal the bottom edge of the sonotube with duct tape, and complete the concrete pour no more than 4 hours after the Sonotube has been exposed to water.