what is the allowable limit for vdf concrete and is code for that

Dnyan Deshmukh

Staff member
VDF is the process of removing excess water from the concrete.

VDF stands for Vacuum de-watered floor

this process take out the excess water (Less voids due to the de-watering) and reduce the porosity of the concrete and get waterproof quality of concrete..

excess water removal may help in faster hydration process.

It improves the shrinkage cracks resistance.

Can you please write in details, what do you mean by limits.

There is as such no special IS Code for it.
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Dnyan Deshmukh

Staff member
There are as such no limits for flatness of concrete top not given in any IS code which speaks about concrete.

In General tolerance for flatness of surface is + / - 5mm or as per the your company tolerance limit.

For slope in the flooring - there may be a sum pits in the surface, which are not acceptable as no one will like the stagnant water on the way or in their car park.

It is must to check the over all slope of flooring you want to give befor starting the casting of panel.

VDF is generally done by casting panels.

so it is important to fix the guide channels in level as per the requirement of slope (in case where PCC not done in slope or on undulated base)

Problem occurs for slope even though the slope is maintained during fixing profiles.

Main cause of it is the floater action
the person operating floater is not experienced.

the blades of floater damaged / not moving correctly.

floating is done either too early or too late.

to ensure the correct slope we can check the undulation on surface immediately after floating by using line thread and get it corrected before moving to next panel.

Only tolerance for level variation after completion of VDF floor - Water should not get stagnant at any place in the panel and it should move towards the slope.

Variation only get observed later if water do not move. (we can not make surface exactly in plane which is required, but we can make it to solve the purpose of it i.e. - slope is given to facilitate rain water or any other spilled water on surface to move into drain and keep surface dry)

Hope this has answered your question, if its not you were looking for then please reply.


There is no as such IS code. But for industrial floors following codes shall be used;
IS 4971:-Selection of Industrial Floor Finishes.
TR 34: Concrete Industrial Floors - The Concrete Society.
ACI 360: Guide to Design of Slabs.
EFNARC: European Specification For Sprayed Concrete & SCC.
FeRFA UK (Federation of Resin Formulators and Applicators).

Harikiran N

Junior Member
I asking after completion of Vdf floor checking of slope what is the tolerance for level variation in concrete top surface.
Laser Screeding is the modern way to do the concrete flooring. This technique allows us to lay concrete floors in wider bays of any size. It drastically reduces Time, Labor, number of Construction Joints and eventually improves the flatness of floors. With this technique it is possible to lay concrete floors up to 3,000 Sqm per day. It eliminates the need of fixing guide rails to every 4 meters. Laser screed simultaneously cuts, vibrates and levels the concrete in a single pass. All these operations are controlled by laser transmitter, receivers and computer. So, manual errors are eliminated thereby giving us Zero Level Difference floor (Super Flat).