Concrete Placement, getting it right

Getting a perfect polish, starts before you actually arrive on site. Concrete finishing and placement can play a big role in a lot of defects in the final polish.

These defects or imperfections are usually brought back on the polisher as something they haven’t done right.

Understanding finishing and placement can help you to educate your concreters on how you want the slab placed or finished in order to give your client the perfect floor.

Make your floor be the picture that everyone is envious of.

THESE DAYS THERE ARE 3 DIFFERENT TYPES OF METHODS THAT 99% OF CONCRETERS WILL USE TO FINISH EVERY SLAB.

• TRADITIONAL SCREED
• POWER TROWEL
• LASER SCREEDING

2 COMMON TYPES OF REINFORCEMENT USED IN MOST CONCRETE SLABS

Rebar is the most common type of Reinforced used.

Wire mesh is commonly used for non-structural slabs.

TRADITIONAL SCREED

Lowest Level

This has widely been regarded as the most common method in concrete finishing yet the least effective. Typically a screed bar is used or a piece of wood, meaning floor flatness is not as accurate as other methods.

As you can see in the picture there are screed marks visible in this floor which cannot be removed and is due to the concreter resting his screed which pushes down the aggregate underneath.

VIBRATORY SCREEDING

Middle Level

Vibratory screeding uses power to better level the concrete surface.

• Reduced muscle power required, a finisher can work standing up and the vibration of the motor on the screed helps to smooth the concrete.
• Often used on smaller residential or commercial projects. Larger projects often will make use of the larger equipment to get in where space permits.
• Screed bars are easy to attach, remove, and replace, and they come in different sized lengths. The longer the screed often the more awkward and heavy it is to work.

LASER SCREEDING

Highest Level

• Laser Screeds set the standard for large concrete pours and ensure your

concrete is finished flat.

• Most precise levelling method
• Commonly used for polished concrete floor projects
• Mechanically powerful and faster than alternative methods
• Laser screeds ensure a faster installation time of the concrete

CONCRETE FINISHING BEST PRACTICES

There are several types of attachments used under screed machines. Where a concrete floor is being poured to polish we have identified the best attachment to be the PAN to get the best and flattest possible finish.

PAN’s help to ensure 15-20% flatter finish than Screed finish.

Float pans move material and flatten the floor more because of the weight but they do not tighten the slab.

POWER TROWEL BLADES

When finishing with a PAN blade to move a lot of concrete, filling in the lows and taking off high sections – we recommend your concretor uses either Plastic or Teflon blades to finish off.

Finish Blades help to ensure the hardest possible finish. These blades help to get he

concrete to it’s hardest point before being blackened or burnt.

COMMON PROBLEMS WITH EDGING

• If the edges of the floor are not finished properly, they become more challenging to polish and make consistent with the rest of the floor
• Hand trowelling does not work well for polishing, as the colour and texture difference will show
• Our recommendation is to use a Power Trowel over the edges across a form, or adjacent slab, to give a tight finish to the edges a power trowel used in an anti-clock wise direction will compact the slab more than a hand trowel will. It will eliminate problems that occur, as seen in the picture. Because this was done with a hand trowel you can see the floor is not as tight and will polish up differently.
• By making the finishing and placement right you will eliminate a lot of problems in the higher polishing steps
• A l ittle care and patience during the floor pour will help make easy polishing!