Power float
A power float is a hand-operated machine used to produce a smooth, dense and level surface finish to insitu concrete beds. Power floating eliminates the time and materials needed to apply a finishing screed and is quicker and less labour-intensive process than hand trowelling.
Power floats have an electric motor or petrol engine fixed over a circular pan or skimmer which smooths concrete before hardened steel reversible metal blades rotate at up to 150 rpm over the surface to create a hardened finish.
Before power floating the concrete must be left to partially set, having been leveled and tamped. The amount of setting time necessary before power floating will depend on variables such as; air temperature, humidity, the specification of the mix and so on. A rough guide for considering when to begin power floating is when walking on the surface leaves indentations of 3-4 mm. If the concrete is too wet the machine will tear up the surface, and if it is too dry, it will not be possible to trim high spots or fill low spots effectively.
Floating usually starts at one end of the slab and moves to the other. The operator holds the float at waist-height and moves backwards so that the float removes their footprints. The speed should be slow and consistent.
Once the surface has been floated, the blades are angled to suit the concrete and achieve the specified finish. Blade angles of around 5-10 degrees are usual, but these may need to be increased after each pass over the surface.
[edit] Find out more
[edit] Related articles on Designing Buildings Wiki
- Bituminous mixing and laying plant.
- Breaker.
- Cement.
- Cherry pickers.
- Compressed air plant.
- Concrete.
- Concrete vs. steel.
- Concreting plant.
- Construction plant.
- Construction tools.
- Crane supports.
- Earth-moving plant.
- Equipment in buildings.
- Excavating plant.
- Screed.
[edit] External references
- Speedcrete - Power floating tips
- ‘Building Construction Handbook’ (6th ed.), CHUDLEY, R., GREENO, R., Butterworth-Heinemann (2007)
Featured articles and news
It was the tallest structure in the world for 3,800 years, but to this day the exact construction techniques are a mystery.
Shortlist for the industry's most coveted award announced.
Government responds to Mark Farmer's review of industry, rejecting the call for a levy on clients.
Peter Hansford to examine what wider lessons can be learned from the fire.
Every project is subject to uncertainty. How can construction better understand uncertainty for performance improvement?
MAD Architects reveal their designs for a futuristic campus for electric car manufacturer.
Homebuyers could borrow more with better forecasting of energy bills, according to industry consortium's new report.
Read our introductory article on carbon capture and storage.
Have a look at Frank Gehry's Binoculars Building in Los Angeles.
BRE publish new Loss Prevention Standard seeking to minimise fire risk from ducting.
Beneficial infrastructure projects
How do we tell which infrastructure projects will work?
CIAT announce the establishment of a Working Group in light of Grenfell and call for contributions.
In 1900, 15% of global population lived in cities. Now it’s over 50%. Which is why we need ‘hydroinformatics’ to consume smarter.
Have a look at these competition-winning designs for a new residential development in Eindhoven.
Grenfell Tower articles updated daily