Last step – get rid of all the marks left by the edging process and create the finished surface of the concrete. You'll want to either float your surface with a wooden float or trowel it for a smoother finish. You can get a rougher feel with just floating the concrete.
This is critical in eliminating small defects or holes and ensuring the end product has a smooth, uniform appearance. Concrete bull floating is a significant part of achieving a professional quality finish on a concrete slab.
No one wants an uneven, rough concrete surface, and that's why it's so important to trowel finish concrete. Troweling ensures a smooth, sleek appearance on your concrete slab that's free from imperfections. It can also prevent the likelihood of needing to sand concrete surfaces or otherwise repair them down the road.
Water will appear on the surface. Wait until this “bleed” water and sheen disappear entirely before edging, jointing or floating the concrete. Screeding levels the concrete with the top of the forms and begins the process of forcing the larger aggregate below the surface.
It's better not to pour concrete directly onto the dirt. Instead, use a layer of gravel underneath your concrete slab. Because concrete is porous, it absorbs water. If you place concrete directly onto dirt, water will collect under the concrete and slowly erode the bottom of the pad.
Skipping the gravel layer under a concrete project might seem like a way to save time or money, but it can lead to significant problems in the long run, including: Cracks and Surface Damage: Due to poor drainage or uneven settling, cracks can develop, which weaken the structure and lead to costly repairs.
You're excited to pour concrete over soil, but hold on! It's not as simple as it seems. Proper preparation is key to avoiding cracks, settling, and moisture issues. Start by compacting the soil and adding a stable base of crushed stone or gravel.
More often, premature finishing or improper first (bull floating) or second floating results in trapping rising bleed water and air below the top surface of the concrete (Image 2). When this occurs, the resulting weak or soft zone below the surface causes the top surface of the concrete to flake or scale off.
Because the action of power floating essentially recompacts the concrete floor, plastic-shrinkage and cracking potentially caused by the concrete drying too quickly is closed together again. The smooth finish also means that the concrete floor is less susceptible to cracking in the future.
GENERAL PRINCIPLES OF FLOATING AND TROWELING
Floating embeds coarse aggregate, removes humps and valleys and compacts the concrete surface. The concrete surface must be sufficiently hard and free of bleed water before power floating begins. Troweling is done after floating to produce a dense, smooth, hard surface.
Magnesium float: You will use a Magnesium float (Lexan float advised on white concrete) about 30-60 minutes after the concrete is placed, when it starts to have a dull, dry look. Again, this timing will vary depending on several factors.
First of all, wet concrete will not bond to dry concrete, hence the need for a bonding agent. It also doesn't adhere to paint, as paint is another material that is often made without any bonding agents. It also won't adhere to mortar and glue has absolutely no effect on it.
If it loses too much moisture through evaporation, it will not cure properly and will become prone to cracks. Many construction specialists recommend watering it down five to ten times per day, for the first week, starting 2-4 hours after it has been poured.
Trowel or Float Finish
This is great to apply on exteriors and can provide non-slip features. This is also your option if you want a solid, durable surface to withstand heavy traffic or intense weather. On the other hand, a float finish is more suitable if you aim for a smoother and more polished look.
Concrete troweling is an important step in ensuring a smooth, level surface on concrete slabs. By repeatedly rolling the surface with a hand trowel or power trowel, it allows the top layer of concrete to set before the final set. This gives the concrete time to level out and harden, resulting in a smoother surface.
Finally – Floating or Troweling
Last step – get rid of all the marks left by the edging process and create the finished surface of the concrete. You'll want to either float your surface with a wooden float or trowel it for a smoother finish. You can get a rougher feel with just floating the concrete.
Floating concrete structures allow the use of marine spaces with important developments for urban areas, industrial plants, infrastructures and energy production.
Because of the danger of scaling or blistering, troweling of air-entrained exterior flatwork is not recommended. Don't hard trowel air-entrained concrete surfaces that will be exposed to freezing and thawing, deicing agents or both.
You can pour concrete on top of an existing slab as long as it's still in reasonably good condition and structurally sound. This means the concrete should be free of cracks, buckling, and breaks. If you notice any small cracks or minor issues, it's in your best interest to repair them before you pour the new concrete.
To get the strongest finish out of your new concrete slab for years to come we suggest taking the time to properly cure your new slab for at least 7 days after installation (28 days is ideal). Curing is the process of controlling the rate and extent of moisture loss from concrete during cement hydration.
If you don't put gravel under concrete, the concrete can crack, sink, bow, or crumble. Even the concrete forming process will not go as smoothly if you are working directly on the soil or bare bedrock.
Watering: If the soil is too dry, lightly water the area a day before pouring the concrete. This allows the soil to absorb the water and reach the desired moisture level without becoming too wet. Drying: For overly wet soil, allow time for the area to dry out naturally.
A sub-base is a layer of aggregate material, such as gravel, crushed stone, or sand, which is placed on the sub-grade (the ground soil) before the concrete base is installed. It is a critical part of any paving or concreting project as it provides support and stability to the concrete base.