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Fill Voids, Sand, and Seal

8:22
11:06
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At 8:22 in

DIY Concrete Countertops For DUMMIES

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What happens here

Upon demolding, you may notice small voids or air bubbles on the surface. To address these, mix Portland cement with water to a 'pudding' consistency, similar to wood grain filler. Apply a thin layer of this cement paste over the entire surface of the slab, pushing it into all the small holes and voids with a trowel. Allow it to dry. Once dry, use a 6-inch drywall knife or scraper to scrape off the excess dried cement, ensuring the filler remains only in the voids. Repeat this process a few times if necessary until most voids are filled. Next, wet sand the surface using a sanding block with 1500-grit wet-sanding sandpaper and a spray bottle filled with water (HDX sprayer). Continuously spray water onto the surface while sanding to create a slurry that helps achieve a smooth finish and prevents dust. Finally, once the slab is completely dry, apply a concrete sealer (e.g., Sealer's Choice Gold). Pour the sealer onto the surface and spread it evenly with a cloth, allowing the concrete to absorb as much as possible, much like a sponge. Leave a generous amount on top for maximum protection and a long-lasting finish.

Goal: Refine the concrete surface, fill imperfections, and protect it with a sealer

Tools and materials

  • Cloth — Wiping on concrete sealer
  • Drywall Knife — Scraping off excess dried cement paste
  • Gloves — Protecting hands during filling, sanding, and sealing
  • Sanding Block — Holding sandpaper for wet sanding
  • Spray Bottle HDX — Applying water for wet sanding
  • Trowel — Applying Portland cement paste to fill voids
  • Portland Cement — Mixing a paste to fill voids in the concrete surface
  • Sealer's Choice Gold Sealer Aqua Mix — Protecting and sealing the concrete surface
  • Water Tap water — Mixing cement paste and wet sanding
  • Wet-Sanding Sandpaper — Smoothing the concrete surface

What they say

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oh yes at this point you probably notice not all voids were filled but don't worry don't freak out there's a way to fix this pick up a bag of Portland cement from the hardware store it's like five or ten bucks mix it up into the consistency of pudding and start applying like you would wood grain filler a slim thin amount on top pushing it into all the little holes all the little voids do that a few layers I found that just doing the entire slab just helps you speed up the process once it's dry then scrape it off then apply another amount and spray it off then take like a six inch finer finishing drywall knife and scrape all the dry stuff off the top this will really help ensure that you don't pull any of the stuff out of its pores you know first I'm not a fan of wet polishing countertops simply because I feel like it opens up far more pores and creates these voids you got to go back and patch instead the simple solution that for me was to get a sanding block with some wet sanding sandpaper 1500 grit and then a spray bottle and do my own manual version of the wet sanding on the countertop keep in mind it's now gonna create it to be that glass slippery smooth granite feel but this is concrete it's supposed to have some of the rough textures and the voids and with the sealer it comes out really well so I guess it's a perfect segue for the sealer the sealer uses the sealers gold choice from Home Depot it worked just fine I didn't have any issues with it I haven't had too many experiences using sealer so I don't really have much to compare to but it applies very well once the granite is dry just pour it on top leave as much on top as you can for the granite to actually absorb it it works like a sponge the more pours that are absorbed and soaked then the more sealant is there and protected [Music]

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