How to use Walttools Stampable Overlayment.
Overlays are a great, but underutilized, segment of decorative concrete. They allow you to take an old, plain, ugly slab or floor and transform it into a textured decorative surface, just like stamped concrete, without starting over. The following is an overview of the process.
It is important that the concrete you are going to use the overlayment on is structurally sound, clean, unsealed, or unpainted. Make sure it also free of curing compounds if this is a newer slab. The existing concrete should be at least 30 days old. The slab will need to have a good profile so that the Over Eze has a good surface to bond to long term. Typically that is done with shot or sand blasting, grinding or acid etching.
Clean & Degrease, Prep-
- Degrease the concrete surface with C Cleaner. Mix according to the instructions, scrub it into the surface and clean thoroughly with water when finished. Make sure any latent oil or grease is not beading water in spots.
- If shot blasting or grinding is your prep, proceed and completely rinse off any dust and residue. If you are not able to do either of those surface treatments, then etch the concrete surface with C Etch, a concrete etcher and remover. Mix according to instructions, work it into the surface and rinse and clean thoroughly when complete. Repeat if needed. The surface should feel soft like sandpaper.
- Protect all adjoining areas with plastic sheeting ir similar material to protect from the application of the overlayment system.
- Apply Colloidal Tru Hard. Colloidal Tru Hard is a very economical concrete treatment that will reduce the transmission of moisture up thru the slab. Most overlayment failure comes from a failure to bond issue. This products is a specialized concrete densifier that will improve the integrity of the slab and serve as a prebonder, improving bond strength overall. Apply in two treatments allowing the first to dry before the second. Saturate and use a broom to eliminate puddling. Allow to dry for 24 hrs.
- Applying the bonder. Mix Flexy Bo bonder 1:1 with water and apply to the surface with a 3/8 nap roller. Roll thoroughly to avoid any puddling or obvious excess material bands from the roller. Allow to dry 1 to 12 hours before beginning the overlayment. Do not exceed 24 hrs.
- If you have any major low points(more than 3/8 inch) from spalling, delamination, etc, you may want to apply a “bond coat”, filling those depressions. This is done by mixing up a batch of the overlay and filling those areas. You may use a broom to apply some profile to that surface before it cures out.
- If you plan to use stencils, you will often color a few batches a contrasting color that will show when the stencil is removed, this layer is applied very thin, just as described in the following section. You will then place your stencils on this initial surface before applying your second coat.
Apply the Over Eze-
- Mix each bag of Walttools OverEze with one gallon of water to achieve a thick batter consistency. If you scoop up a handful of mix with an open finger palm, some of the material should run out between your fingers. You can use up to another 16 ounces to loosen the mix if needed. If you are adding integral color now is the time to do so and blend fully.
- Use a gauge rake set at 1/4” to 5/8” spread the material over the surface, setting your depth. You can then immediately use a hand mag float, darby or concrete squeegee to smooth out the gauge marks, preparing the surface for the trowel. You will typically do those process one or two bags at a time. Do not just dump several bags of wet material on the ground in piles and expect to spread it out evenly later.
- Pay attention to existing control joints. They will likely crack thru if you bury them. Mark the locations of the joints. You will use a saw to cut thru when the material cures.
- For cleaner impressions, do this step. Wait until the material stiffens up and much of the surface sheen will disappear. The material will not be very stick at this point. You can then take a clean steel trowel and trowel smooth the surface. Wait a few more minutes and the material should be ready to stamp. Place your finger into the material. It should be stiff but pliable and not stick to your finger.
- If stencils are being used, you will proceed with light texturing with skins or texture rollers. Pull your stencils once the material stiffens up a bit more.
Apply Release Agent – Liquid Release or Powder
- Apply Walttools Liquid Release with a pump sprayer to the stamping tool and the immediate area that will be textured. You will apply release on both the tools and surface as you go. Avoid troweling the release into the surface. If you have a major correction, do the minimal troweling of the surface to make the correction.
- Do not apply too much release. This can actually create suction between the surface and the tool resulting in a non-crisp impression.
Release Agent – Powder Release
- Broadcast a thin application of Walttools concrete accent powdered release agent to the surface. You only want enough to “dust the surface” and you will easily see where it covers the overlayment. Dust your tools lightly with the release as well. Never trowel release into the surface. If you have a correction, use a texture skin and grout tool, DO NOT SMOOTH OUT AND RESTART. Dust your tools lightly with the release as well.
- Make sure you are familiar with your stamps before you pour. Time is more critical with overlay than concrete and you do not have room for errors. Make sure your stamps are suitable for overlayment. Some stamps r too aggressive for a thin applied overlayment and will “bottom out”, leaving almost no material unde the groutlines. This leads to cracks and failures. Walttools has a category of stamps more suitable for typical overlay jobs.
- You should have enough stamps to create a full row and one or two to start the next row. Make sure you have both a floppy and touch up skin for working around walls and other obstacles.
- As you lay out the stamps on the surface, carefully walk and/or tamp them into the surface. Be very carefully as you walk from one stamp to another as overlayment can have a tendency to slide. Lift the corner of a stamp to be sure you are getting proper texture.
- If interior, keep a matching Walttools 9” texture roller with you and as you approach walls apply texture along the edge and near other obstacles that are difficult to stamp cleanly.
- Use a Walttools grout tool or touch up roller to correct joint lines as you go. If some are missed, they are easily removed the next day with a grout saw.
Next Day-12 to 24 hrs
- Clean the surface of the release agent. This is even more important if you use powder release. If interior, shop vac the excess release using little soap and water with a broom to agitate and loosen the release. You should only leave about 20 percent of the release, highlight the grout lines and texture. Keep cleaning until the surface is clean of any non-adhered release.
- Using the grout saw, touch up any grout lines that were missed. For any rough surface areas you can use a rub stone or hand diamond pad to knock down.
- Overlayment can be colored with a number of stain systems. Tru tint Acid Stains, Reax stains, or Water Base stains. If you used liquid release, you can also add easy contrast by using Tru Tique color wash-an antiquing agent.
- If you are using stains, remember that stain systems may work differently on overlayment then they do on concrete. It is a good idea to have made a couple of sample boards (use cement board)when you installed the overlayment just for testing purposes. It is always better to have a good idea about what is about to happen than just assuming.
- Apply two thin and even coats of a chosen sealer using the proper application tools. Spraying or rolling on are most common. There are many sealers to choose from depending on the protection needs, environment and aesthetics desired. Make sure the sealer you are using is designed for the environment at hand. Generally solvent based sealers are used outdoors and low solvent or water based sealers are used inside.
There you have it. A good overview and scope of an overlayment install using Walttools Over Eze and related products. Do not hesitate to call Walttools for support on a particular project or to get more information regarding the products discussed here.
Bear in mind, that Over Eze is a very versatile, user freindly product. Though designed for stamping, it can easily be used to simple resurfacing, knock down finishes, and hard trowel looks. Available in gray or white, it can help transform many tired concrete suraces into something grand.