Formwork in concrete construction, also called shuttering, is a structural mold in which fresh concrete is poured and hardened. Here are some things you should know about concrete formwork:
The construction of concrete formwork is no small undertaking; it takes time and can cost up to 25 percent of the total price of the structure. Luckily, stripped concrete formwork can be reused to reduce time and cost. Reusable forms are known as “panel forms,” while non-reusable concrete forms are called “stationary forms.”
Across the different construction sectors, timber is the most common material used for concrete formwork. The timber should be well-seasoned, lightweight, easily workable, and free from loose knots. The downside of using timber concrete formwork is that it will warp, but the application of water-based treatments to the surface of the wood can help reduce this effect.
In addition to timber, concrete formwork can be made out of steel, plywood, and fiberglass. These materials can be used separately or together.
The most common type of concrete formwork used in heavy civil construction is steel! Steel formwork consists of panels created from thin steel plates that are stiffened along the edges by small steel angles. The panel units are held together with clamps or bolts and nuts, and can be produced in large quantities in any shape or size. Steel formwork is stronger, more durable and has a longer life than timber formwork, and it will not shrink or warp.
Formwork can also be crafted from resin-bonded plywood sheets. The sheets are attached to timber frames to make up the formwork’s panels. The cost of plywood formwork is comparable to that of timber formwork, and can sometime be cheaper.
Fiberglass made of precast concrete and aluminium is used in cast-in-situ construction such as slabs or projects involving curved surfaces.
A good formwork should be strong enough to withstand all types of loads, but it should also be as light as possible. The formwork should be constructed rigidly and braced both horizontally and vertically, so as to retain its shape. Similarly, the joints in the formwork should be tight against leakage and should rest on a firm base.
Though formwork constitutes a large portion of the cost of a structure, these costs can be reduced. In order to reduce the cost of formwork:
The plan of the building should include a minimum number of variations to the sizes of the rooms so that the formwork can be reused
The design of a building should use as few slender sections as possible
Minimum sawing and cutting of wooden pieces should be made so that the material can be reused multiple times
Formwork Can Sometimes Be Removed Early
Quickly hardening cement, warm weather and light loading conditions can allow for the early removal of formwork. Formwork should not be removed until all the concrete is able to withstand at least twice the amount of stress and pressure that the structure is expected to undergo. No matter when the formwork is removed, it should always be eased away gradually so that the load is slowly transferred to the concrete.
Because of its strength and long working life, there is a great used market for concrete formwork made of steel. Reselling concrete formwork after a project is a great way for contractors to make money. In addition, purchasing used and surplus formwork for a project is an equally great way for contractors to save money.
In addition to concrete formwork, Eiffel Trading’s online marketplace hosts a wide variety of concrete equipment, including overhang brackets and concrete placing booms. Furthermore, our used material inventory ranges from used barrier wall to used and surplus sheet pile, and everything in between.
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When I do overlays in 1 pour, I have never screwed anything to the floor.
On pours to the walls I purchase fur veneer (I live close to several plywood plants).
I put veneer strips at the Sheetrock so it won’t suck up the water from the pour. the thin strips can be pulled or cut off and the base boards will hide them.
I use a bull float to flatten it out if I need screed boards I hang them up on the wall(s) and will have one set loose in the middle pour both sides and the center last and float it out
I see no reason to screw to the slab if I only do a section. I would use the wall for support with horizontal bracing, I don’t like drilling basement slabs because of leaks that can be caused.