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Formwork (shuttering) in concrete construction is used as a mold for a structure in which fresh concrete is poured only to harden subsequently. Types of concrete formwork construction depends on formwork material and type of structural element.

Formworks can also be named based on the type of structural member construction, such as slab formwork for use in a slab, beam formwork, column formwork for use in beams and columns, respectively, etc.

The construction of formwork takes time and involves expenditure up to 20 to 25% of the cost of the structure or even more. The design of these temporary structures are made to economic expenditure. The operation of removing the formwork is known as stripping. Stripped formwork can be reused. Reusable forms are known as panel forms and non-usable are called stationary forms.

Timber is the most common material used for formwork. The disadvantage with timber formwork is that it will warp, swell, and shrink. The application of water-impermeable cost to the surface of wood mitigates these defects.

Requirements of Good Formwork

  1. It should be strong enough to withstand all types of dead and live loads.
  2. It should be rigidly constructed and efficiently propped and braced both horizontally and vertically, to retain its shape.
  3. The joints in the formwork should be tight against leakage of cement grout.
  4. Construction of formwork should permit removal of various parts in desired sequences without damage to the concrete.
  5. The material of the formwork should be cheap, readily available, and should be suitable for reuse.
  6. The formwork should be set accurately to the desired line, and levels should have a plane surface.
  7. It should be as light as possible.
  8. The material of the formwork should not warp or get distorted when exposed to the elements.
  9. It should rest on a firm base.

Economy in Formwork

The following points are to be kept in view to effect economy in the cost of formwork:

  1. The plan of the building should imply a minimum number of variations in the size of rooms, floor area, etc. to permit reuse of the formwork repeatedly.
  2. Design should be perfect to use slender sections only in the most economical way.
  3. Minimum sawing and cutting of wooden pieces should be made to enable reuse of the material many times. The quantity of surface finish depends on the quality of the formwork.

Formwork can be made out of timber, plywood, steel, precast concrete, or fiberglass used separately or in combination. Steel forms are used in a situation where large numbers of re-use of the same forms are necessary. For small works, timber formwork proves useful. Fiberglass made of precast concrete and aluminium are used in cast-in-situ construction such as slabs or members involving curved surfaces.

Types of Formwork (Shuttering)

1. Timber Formwork

Timber for formwork should satisfy the following requirement:

It should be:

  1. Well-seasoned
  2. Light in weight
  3. Easily workable with nails without splitting
  4. Free from loose knots

Timber used for shuttering for exposed concrete work should have smooth and even surface on all faces which come in contact with concrete.

Table 1: Normal sizes of members for timber formwork

Sheeting for slabs, beam, column side, and beam bottom25 mm to 40 mm thick
Joints, ledges50 x 70 mm to 50 x 150 mm
Posts75 x 100mm to 100 x 100 mm

2. Plywood Formwork

Resin-bonded plywood sheets are attached to timber frames to make up panels of the required sizes. The cost of plywood formwork compares favorably with that of timber shuttering, and it may even prove cheaper in some instances given the following considerations:

  1. It is possible to have a smooth finish in which case on cost in surface finishing is there.
  2. By the use of large-size panels, it is possible to affect saving in the labor cost of fixing and dismantling.
  3. The number of reuses are more as compared with timber shuttering. For estimation purposes, the number of reuses can be taken as 20 to 25.

3. Steel Formwork

This consists of panels fabricated out of thin steel plates stiffened along the edges by small steel angles. The panel units can be held together through the use of suitable clamps or bolts and nuts.

The panels can be fabricated in large numbers in any desired modular shape or size. Steel forms are largely used in large projects or in a situation where large number reuses of the shuttering is possible. This type of shutter is considered most suitable for circular or curved structures.

Comparison between Steel and Timber Formwork

  1. Steel forms are stronger, durable, and have a longer life than timber formwork and their reuses are more in number.
  2. Steel forms can be installed and dismantled with greater ease and speed.
  3. The quality of exposed concrete surface by using steel forms is good and such surfaces need no further treatment.
  4. Steel formwork does not absorb moisture from concrete.
  5. Steel formwork does not shrink or warp.

Construction of Concrete Formwork

This normally involves the following operations:

  1. Propping and centering
  2. Shuttering
  3. Provision of camber
  4. Cleaning and surface treatment

Order and Method of Formwork Removal

The sequence of orders and method of removal of formwork are as follows:

  1. Shuttering forming the vertical faces of walls, beams, and column sides should be removed first as they bear no load but only retain the concrete.
  2. Shuttering forming soffit of slabs should be removed next.
  3. Shuttering forming soffit of beams, girders, or other heavily loaded shuttering should be removed in the end.

Rapid hardening cement, warm weather and light loading conditions allow early removal of formwork.

The formwork should under no circumstances be allowed to be removed until all the concrete reaches a strength of at least twice the stresses to which the concrete may be subjected at the time of removal of formwork.

All formworks should be eased gradually and carefully in order to prevent the load from being suddenly transferred to concrete.

Figure 1 to 6 shows formwork for different types of members in civil engineering construction.

Types of formwork - Details of timber formwork for RCC beam and slab floor
Figure 1(a): Details of Timber Formwork for RCC Beam and Slab Floor
Details of timber formwork for RCC beam and slab floor
Figure 1(b): Details at Section (A) Shown in Above Figure
Details of timber formwork for circular RCC column
Figure 2(a): Elevation
Details of timber formwork for circular RCC column
Figure 2(b): Details of Timber Formwork for Circular RCC Column
Details of timber formwork for square or rectangular RCC column
Figure 3(a): 150 3D View
Details of timber formwork for square or rectangular RCC column
Figure 3(b): Details of Timber Formwork for Square or Rectangular RCC Column
Sectional plan showing details of timber formwork for an octagonal column
Figure 4: Sectional Plan Showing Details of Timber Formwork for an Octagonal Column
Details of formwork for stair
Figure 5: Details of Formwork for Stair
Timber formwork for RCC wall
Figure 6: Timber Formwork for RCC Wall

Table 2: Period of Removal of Formwork

S. No.Description of structural memberTime Period
1Walls, columns and vertical sides of beams1 to 2 days
2Slabs (props left under)3 days
3Beam soffits (props left under)7 days
4Removal of props to slabs
(a) For slabs spanning upto 4.5 m7 days
(b) For slabs spanning over 4.5 m14 days
5Removal of props to beams and arches
(a) Spanning upto 6 m14 days
(b) spanning over 6 m21 days

FAQs on types of formworks and their properties

?What are the types of formworks?

1. Timber formwork
2. Plywood formwork
3. Steel formwork

?What is formwork in building constructions?

Formwork is used to describe the process of building temporary molds in to which fresh concrete is poured to construct designated structural concrete elements and achieve its shape.

?What are the requirements of formworks?


1. Adequately strong to withstand all types of loads.
2. Rigid enough to retain its shape.
3. Joints in the formwork tight against leakage of cement grout.
4. Formwork construction should permit the removal of various parts in desired sequences without damage to the concrete.
5. The formwork material should be cheap, readily available, and reusable.
6. The formwork should be set accurately to the desired line, and levels should have a plane surface.
7. It should be as light as possible.
8. It should rest on a firm base.

?How much does a formwork cost in comparison to the total cost of the structure?

The construction of formwork takes time and involves expenditure up to 20 to 25% of the cost of the structure or even more.

?What are the requirements of timber formwork?

1. Well-seasoned
2. Light in weight
3. Easily workable with nails without splitting
4. Free from loose knots

Read More:

Plastic Formworks for Concrete – Applications and Advantages in Construction

Wooden Concrete Formwork Design Criteria with Calculation Formulas

Concrete Formwork Loads and Pressure Calculations

Formwork Removal Time & Specifications

Measurement of Formworks

Formwork (Shuttering) for Different Structural Members -Beams, Slabs etc

Formwork Safe Practices Checklist

Gopal Mishra

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106 Comments

  1. thanks for that information this is very useful to us

  2. The above information is very good but valuable to the beginners. If you can take the details to the depth, our community will take the benefit.
    If you can discuss the details of Plastic and Aluminum form work, the economy in the number of turns would benefit the construction field as a whole.

  3. Arianne,

    If you want to take an innovative study, please consider the following fields.
    1. Foundations – Our foundation cost on any structure is very high. Take a study and compare with one another and deliver a paper that the one which is economical.

    2. We are spending more on Form works. Take a study on different form works being used. Aluminum and Plastic form works are out in the market for commercial use. I understand from my experience, the plastic forms are efficient in handling, increase the out put and the number of turns is from 40 to 50 times, whereas wood is very costly. Your technical paper will get appreciation.

    Many more are there on the list.

    Try these two first and see your out put.

    Regards,
    Janardhanan
    Qatar

  4. I am into a Timber Formwork with encapsulated High Density Thermocol – the Thermocol is not removed and stays in place to provide Thermal Insulation

  5. Thanks for the useful information, we are manufacturing plasticformwork, if someone wants to have more information. plz sendcur enqry to info@sisconformwork.com

  6. Er Niraj Kumar after 7 days v shld get 70% of the strength.

  7. Prince Jacob is there any way to check the supports? that what i meant

  8. can u plz tell what all tests are there to check the quality of formwork.

  9. I would be grateful if your technical study took into account the possibility of use of: stone (basalt), raw land and insulating materials entirely organic. Thanks

  10. Attn! Attn! attn! everyone………
    we r the manufractures of steel scaffolding & formworks products. we r JVR FORGINGS LTD.Everyone who have required pls contct me. Rishi Singh or rishisingh@jvrforgings.com.

  11. Thank you for this info – maybe you can compile an article on moladi plastic formwork – http://www.moladi.net.

  12. Er Niraj Kumar . Steel is the heart of the construction. so, learn how the steel is designed for the building as per S.B.C.(soil capacity) and give quantities of steel in columns, beams and slabs water tanks and checking .

  13. dear can u innovate leveling machine for slab checking without needing leveling just install it and ready to use

  14. Dear Mr.Gopal, I am Rajesh from Sri Raam Traders,Tamil Nadu.I am one of the leading Building Construction MatConterial supplier in my city.And also young growing builder.Basically i have a 3 years experience in Construction field.Last May i was started a New Residance contract work.i have a lot of suggestion in this work.

    I wil send my plan to ur mail.so plsend me email id to my mail.i will send all the details to u.

    Thanks & Regards,

    Rajesh.

  15. hello, Arianne Punzalan
    the main thing is in the field of construction is CONCRETE TECHNOLOGY.

  16. Hi Gopal Mishra.I'm Benjamin Kardel from VietNam.I'm interested in Construction field.your blog containt many posting which are interested.May I copy these post and Links to my Blog? Tks you.
    My blog at: http://www.construction-site-vn.blogspot.com.
    Nice to meet you.

  17. I would like to learn all types of form work methods and designs kindly provide the information about the new methods & demos to improve my knowledge in my construction proffession.Regards,Rajendra.

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