There are many different ways to finish concrete and many different types of finishes you can achieve. Some of the ways include exposed aggregates, broom finish, trowelled smooth, or stamped concrete. Keep on reading to learn how the finishing process works!
Pouring & Leveling Concrete Before Finishing
Before we get to the finishing part, you must first pour the concrete in place. Once it’s poured in place and spread out, the next step would to be level it off or screed it; This is an important step because it removes all the excess concrete and brings the surface to the proper grade. Next is floating the surface! This smooths out the concrete and brings all the bleed water to the surface for the finishing process.
How to Finish Concrete
To get a trowelled finished look, you should have a power trowel for larger jobs. For a smaller job you can wipe it smooth with just a finishing hand trowel, Fresno, or a big "D". Make sure the perimeter of your concrete has been edged using a hand edger if this is required. If you are wiping it by hand, you can begin troweling once the concrete is strong enough to hold your body weight and will leave a footprint no deeper then 1/8".
There is no time frame for this as it strictly depends on the temperature and weather conditions. Knee boards or sliders will be helpful while trowel finishing the far end and middle of the pad. If you are using a power trowel, you can also begin at this time. Again, you can start at the back end and work your way back. You will need to wipe any tight corners with a hand trowel; The power trowels are round and cannot fit into tight areas.
There are three types of blades that can be applied to a power trowel - Finish, Float, and Combo Blades. Most commonly the finish blades are ideal for a very smooth finish. The float blades simply fit overtop of the finish blades like a shoe (They are often referred to as a shoe). The combination blades would need to be switched over with the finish blades. They are great because they are larger than the finish blade, but smaller than a float blade. Combination Blades can be run flat for float finishing or pitched to finish concrete. They are equipped with an angled side to prevent digging.
Now you can start the power trowel! The blades will start to spin, and you can begin moving it back and forth across the pad 2-3 times, allowing the concrete to harden a bit between each pass. When finishing exposed aggregate, there is a retarder that is sprayed on the surface to retard (slow) the set of the surface cement to achieve an exposed aggregate surface.
When ordering your concrete, you will need to order it with more stones. We recommend ordering it with approximately 20% more stones then just your standard redi-mix concrete. R20 surface retarder can be sprayed on as soon as the bleed water disappears. If you have areas that are sloped, the retarder will need to be re-applied in case of any runoff. The Retarder will need to be washed off in about 12-24 hours; This will leave you with a nice washed off exposed finish.
Broom Concrete Finishing
Broom finish is similar to finishing as trowelled, however, prior to the trowelling part you would run a broom across the surface, which leaves an imprint. There is no need to trowel finish broomed concrete, just finish it with a float, and once that’s done, press the broom print across the slab. Make sure the edges are done afterwards and then you can put your groover cut lines in.
Stamped Concrete Finishing
For finishing Stamped concrete, the surface should be hard enough to support your weight, but soft enough to leave an imprint about 3/16"-1/4". You need to apply a release agent over the area; This can be broadcasted with a brush or sprayed on if it’s a liquid. This allows the stamps to peel off the surface with ease and highlights the surface if you add colour to the clear liquid release. All powder releases are coloured.
Depending on the pattern of the stamp you choose, it will depend how many stamps you have to work with. Stamps come in seamless texture skins or patterns. Most patterns come in sets of three (a red, blue, yellow, and then a floppy). They are all the same pattern, but the textures are slightly different to give you a more random appearance.
Starting from one corner, lay one stamp down. They will go together similar to puzzle pieces! Continue by walking in each stamp one at a time. You can even rent hand tampers to help get a good imprint. The floppies are for really tight corners and can be bent in half to ensure you can get the pattern right close up to the house (or anything else that may be in the way). The release agent is washed off about 24 hours after the pour. Make sure you wash it off well to ensure your sealer will stick.
Sealing Your Concrete
Now that the finishing techniques are complete, you will want to make sure you seal your concrete project(s). It’s important to protect your investment! Topical sealers can be used on all of the finishes we covered above, however, the floor that was power trowelled will need to be etched to open the pores up and allow the sealer to stick.
Cure and seal can be applied next day, and high gloss can be applied after 28 days. For the floors that have a broom finish or trowel finish, you can apply a penetrating sealer. It’s recommended to wait until the concrete is partially cured (about 14 days) before applying these.
Products we recommend, available at unicon.ca:
- Retarder for Exposed Aggregate https://unicon.ca/retarders-for-exposed-aggregate...
- Various Release Agents https://unicon.ca/search.php?search_query=release...
- Uniseal – Matte (Unicon Concrete Sealers) https://unicon.ca/search.php?search_query=release...
- Unisheen – High Gloss (Unicon Concrete Sealers) https://unicon.ca/search.php?search_query=release...
- Master Protect H1000 https://unicon.ca/search.php?search_query=release...
- Power Trowels + Hand Trowels + Blades https://unicon.ca/search.php?search_query=release...