In this article today I am gonna show you a safe time period to remove formwork from concrete. There are different de-shuttering times for different structures like a beam, column, slab, stair, etc.
The formwork for concrete structure should be rigid enough during the placing, compacting to prevent the loss of slurry from the concrete.
Types of shuttering (Form work)
- Shuttering for Column
- Shuttering for Beam
- Shuttering for Slab
All rubbish, dust particles, irregularity, chippiness, shavings should be removed from the interior of the formwork before placing concrete in it. Formwork materials should be cleaned and treated with cleaning materials.
Shuttering (Formwork) should not be removed with sudden load or impact on the concrete structure with a hammer or nail extractor.
In normal circumstances where the temperature does not fall below 15-degree Celcius and where OPC has accrued sufficient curing time, the following guidelines have given by IS 456:200 clause 11.3 as the removal time of shuttering or formwork.
When to remove concrete forms in construction?
The removal time of vertical formwork to column, walls, the beam should not be less than 15 hours to 24 hours.
The removal time of Soffit formwork to slabs (Props to be refixed immediately after removal of formwork) should not be less than 3 Days.
The removal time of Soffit formwork to beams (Props to be refixed immediately after removal of formwork) should not be less than 7 days.
The removal time of Props to slabs:
1) Spanning up to 4.5 m should not be less than 7 days.
2) Spanning over4.5 m should not be less than 14 days.
The removal time of Props to beams and arches:
1) Spanning up to 6 m should not be less than 14 days.
2) Spanning over6 m should not be less than 21 days.
Checklist before Shuttering
1) Check weather the materials of shuttering is new or old.
2) Check the shuttering repairs is necessary or nor.
3) Check the cleanness and straightness of shuttering properly.
4) Check weather the shuttering contains oil. If it contains oil, then remove it.
Checklist during fixing of shuttering
- Check the design of shuttering properly
- Check the rigidity, levveling and alignment of shuttering.
- Check the props properly.
- Check the span of shuttering properly.
- Check the brace.
- Check the holes, sealing joints of shuttering.
Checklist after removal of shuttering
1) Check the concrete surface is good or not.
2) Check if any repairment is required for structure or not.
I hope this article on “When to remove concrete forms from Concrete” remains helpful for you.
Happy Learning – Civil Concept
Civil Engineer – Ranjeet Sahani