Stamping concrete is challenging. You may be able to manage pouring and placing the concrete with minimal issues, but if you don’t get the imprinting process just right, you’ll be left with a permanent slab that can be difficult and expensive to repair. The outcome of stamped-concrete-gone-wrong cannot be easily undone. The stamps need to align, the pattern needs to be laid properly, and the texture needs to take right. Add to the mix that the whole process is constrained by time–concrete dries quickly enough to give you only a small window to stamp in.
If you’re not contemplating DIY stamped concrete, then you can be relieved to know you’re leaving all these variables in the hands of an experienced contractor for your project. In that case, take a look at this overview of the stamped concrete process. It’s not comprehensive enough for the DIY-er, but it will give you, as the homeowner or business owner, a basic idea of what will be done when your projects is stamped.
The subgrade makes a big difference in the overall performance and structural integrity of the slab. It must be well-compacted which will help prevent drainage and can prevent soil erosion under the concrete.
Placing the Forms
Forms, made from wood, metal or plastic, are attached to stakes to contain the concrete in the area desired. It is important that forms are in good condition, be set to provide the proper slope or grade for drainage, and are erected to create clean corners where they abut each other or structures.
Using steel reinforcing bars or welded wire mesh are critical to providing structural function and support in the slab. The main reasons to include reinforcement in the slab is to help control cracking, provide structural capacity, increase impact resistance, and reduce joint maintenance.
Placing the Concrete
The most common method for placing concrete is to have the ready-mix truck pull up to the placement area and deposit the concrete from the chute. The concrete should be placed as close to its final destination as possible because moving it around too much (with shovels or other tools) can lead to segregation. Also be sure plastic sheeting is used to protect adjacent buildings, landscaping, or other existing slabs from concrete splatter. The type of concrete used is also crucial to successful placement. Make sure to discuss with your contractor how he plans to avoid issues that can arise without the proper slump, or mix design.
Screeding and Finishing the Concrete
The work done immediately following concrete placement is critical, since this is when you must create the perfect canvas for decorative stamping. The two most important factors are that the surface is leveled to prevent any low or high spots, and that cement paste is brought to the surface to permit a well-defined imprint.
The Stamping Process
The window of time in which to stamp is generally short, especially in warm weather. The stamp layout should be diagrammed ahead of time, and there should be enough labor on hand for the volume of work to be done. Typically, the edges are pre-textured first because later when the larger stamps are used, they may overlap the forms and won’t be able to be fully depressed into the concrete. The concrete should then be stamped in the same sequence it was placed. Stamping alignment should be checked regularly, along with verifying that the correct random patterning is being followed to ensure a realistic-looking outcome.
Curing Stamped Concrete
The goal when curing (or allowing your concrete to dry) is to retain sufficient moisture content for a long enough time to allow the necessary properties of the concrete to develop. With proper curing, concrete becomes denser and less permeable, resulting in an overall increase in strength and durability.
Cutting contraction joints (also called control joints) can help to prevent conspicuous cracks. Although not all cracking can be prevented due to the stress caused by temperature changes and drying shrinkage. Providing stress relief at planned locations can help control random cracking.
Sealing Stamped Concrete
No decorative stamped concrete installation is complete without the application of a sealer. This is the final step and one of the most important. A sealer will help enrich the color of concrete, will add a sheen to the surface (ranging from satin to high gloss), reduces the chance that efflorescence will discolor the surface, and blocks penetration of stains from dirt, chemicals, leaves, etc.
Gegra Equipment has a large inventory of concrete stamps. Give us a call or stop by our shop for more information:
5971 Beresford St, Burnaby, BC V5J 1K4
Email: [email protected]
Hours: Monday to Friday – 7am to 4:30pm