How Are Concrete Block Interior Walls Finished?
When building or remodeling homes with concrete block interior walls in basements, or other areas of their homes, homeowners are sometimes left with interior walls of exposed concrete blocks.

Published: by SEMCO FL
3 Proven Methods: How Concrete Block Interior Walls Can Be Finished
When building or remodeling homes with concrete block interior walls in basements, or other areas of their homes, homeowners are sometimes left with interior walls of exposed concrete blocks. One of the reasons the walls might not be finished yet is because you’ve recently been installing all the plumbing and electrical workings, and so finishing the wall is obviously not possible until all that is done — otherwise you’d have to break into it and destroy all your hard work!
There are 3 main ways that people generally use to finish these concrete walls: painting, pargeting, and wood paneling/drywall, all of which we will describe below. Some may believe that these are the only 3 viable options, but that isn’t the case. In today’s blog, we want to explain how each conventional method can be improved using different Semco applications to create a faster, more efficient, more waterproof and more convenient way to finish concrete block interior walls.
1. Finishing Concrete Block Interior Walls: Painting
Painting is the simplest method of finishing a concrete block interior wall. It’s ideal for those who perhaps aren’t worried about the exposed concrete itself or the visible joints between each block, but perhaps just don’t like the drab color. Painting simply applies a nice colorful coat to the concrete. In a small space like the basement, light and bright colors can help lend a sense of space to the room.
The only slightly complex step required in the painting process is priming, for which it’s best to use a water-based latex primer, followed by your finishing paint. Once the wall is primed and ready, you can treat it like a blank canvas.
Semco Alternative to Painting Concrete Block:
Liquid Membrane
In many cases painting concrete block will do the job. If you have concerns about water or moisture passing through the block, or if you have cracks in the block you may need to up your coating game.
Available in a variety of different colors the Semco Liquid Membrane Waterproofing creates an incredible bond to the concrete. There is no need for a primer and it blocks moisture coming in from outside of the block.
It is also impervious to water damage from the inside and it is highly abrasion resistant.
Here are the application steps:
- Simply roll or spray it on in a two coat thickness.
A yield at two coats (2 coats is standard) is:
- 160 sq ft per gallon or 800 sq ft per 5 gallon bucket. Click here to view a detailed diagram.

2. Finishing Concrete Block Interior Walls: Wood Paneling Or Drywall
Finally, another common practice for finishing concrete block interior walls is placing wood paneling on the walls to create a solid (and hopefully stylish) covering for the concrete blocks and their unsightly joints. Paneling is installed by first attaching horizontal furring strips to the wall with a hammer drill and screws, and then placing tongue and groove pine boards vertically against them.
If you don’t want to use pine boards, you could use something a bit more budget-friendly like drywall. If you use drywall you will have to tape and mud the joints and then apply a coat of paint which adds substantially to labor and material costs. Once the wood is all in place, you can then treat it with linseed oil or similar wood oil to provide protection.
Semco Alternative to Drywall: Semco Liquid Membrane with Joint Compound and Standard Paint Finish
While drywall creates a great finish on walls it is costly, time intensive and dusty! First you have to get ¾” furring strips on the wall by drilling into the wall with a hammer drill. Then you have to put up the heavy sheets of drywall, tape them, apply joint compound and then do multiple sanding and reapplication steps before priming and painting. Using liquid membrane will save a lot of those steps.
Here are the benefits:
- Faster installation
- Less dust
- Totally blocks moisture transfer through the wall
- Reduces the wall thickness
- Costs less
Here are the application steps:
- Clean wall, make sure it is free of dust and debris. If the wall is painted the paint should be removed because the paint will always be a weak link.
- Apply your first coat of Semco Liquid Membrane with a roller or sprayer. Apply at approximately 15 mil thickness (.015 inches). Thicker is not better!
- Once the first coat dries apply your second coat of Semco Liquid Membrane at approximately 15 mil thickness (both coats will be ~30 mil thickness). Yield including the two coats is 160 sq ft per gallon, or, 800 sq ft per 5 gallon bucket.
- Once this is dry you can apply joint compound directly over it. Here are a couple links to this product: a. Lowes joint compound, b. Home Depot joint compound
- Finally, prime and paint your wall.
3. A Better Way To Finish Concrete Block Interior Walls: SEMCO Microcement
These ways are tried-and-tested, but they seem to come with the same underlying caveat: the more you want to cover and finish a concrete block interior wall, the more materials you need to invest in and the more physical labor needs to be done. Semco is a product that breaks this rule, offering a very simple way to retain a stylish, textured concrete finish and the benefits that come from that, but also removing any semblance of unsightly block joints.

How Does Semco Work? Concrete Block Interior Walls
The Semco system is a kind of micro-topping that can be placed over virtually any substrate – including your concrete wall. Once the wall is primed and ready, you can simply trowel on the Semco in layers and then leave it to cure. Once it does, it creates a non-porous, hard concrete-like outer protective shell that simultaneously hides the wall joints and creates a pleasing finish.
If you’re applying Semco in a basement where you have real concerns about water intrusion, then you can double up on Semco’s natural non-porous state by applying the Semco Liquid Membrane full waterproofing solution. It’s actually a far superior solution for basements, where keeping moisture out is an absolute necessity. Plus, if you get a flood in your basement the Semco system will be unaffected unlike with paint, drywall, or paneling.
Semco Microcement Option One 1
Semco Microcement Skim Coat Kit – with your own paint finish
If you want to have a single material that will do all of the following:
- Fill the joints to make a smooth wall
- Provide a waterproof surface from inside or outside that is still breathable
- Ultra-hard material approximately 3500 PSI
Then these are the installation steps:
- Ensure wall is free from dust and remove paint. If you apply over paint it will always be a week point if there is moisture later on.
- Prime wall with X-Bond Liquid
- While primer is still wet apply Scratch coat 1:2 X-Bond Liquid to X-bond Stone, spray with a hopper gun or apply with a concrete broom
- Mix 1:1:2 X-bond Liquid to X-bond additive to X-bond Stone, trowel over wall to smooth out mortar joints, allow to dry
- Apply skim coat of 1:2.5 X-Bond Liquid to X-Bond Stone to create a final smooth finish
- Sand if needed to smooth surface
- Prime and paint (your own choice paint of, a non SEMCO product)
Semco Microcement Option 2
Microcement Decorative Finish Kit – no paint required!
If you want to have a complete kit with all material that will do all of the following:
- Fill the joints to make a smooth wall
- Provide a waterproof surface from inside or outside that is still breathable
- Ultra-hard material approximately 3500 PSI
- Finished Decorative SEMCO Sealer with your choice of Texture/Colorant (no paint required)
Then these are the installation steps:
- Ensure wall is free from dust and remove paint. If you apply over paint it will always be a week point if there is moisture later on.
- Prime wall with X-Bond Liquid
- While primer is still wet apply Scratch coat 1:2 X-Bond Liquid to X-bond Stone, spray with a hopper gun or apply with a concrete broom
- Mix 1:1:2 X-bond Liquid to X-bond additive to X-bond Stone, trowel over wall to smooth out mortar joints, allow to dry
- Apply skim coat of 1:2.5 X-Bond Liquid to X-Bond Stone to create a smoother finish
- Apply second skim coat of 1:2.5 X-Bond Liquid to X-Bond Stone to create a final smooth finish – burnish for decorative Venetian Plaster effect
- Apply Semco sealer Titan or Satin Stone
Benefits Of Semco
1. Semco is a Vapor Barrier
Even without additional waterproofing, Semco provides a non-porous vapor barrier that prevents moisture from getting into your concrete. Where concrete is naturally porous and thus needs to be sealed, Semco creates a protective barrier that will actively protect against any moisture intrusion. At the same time, it provides physical protection for the wall beneath, even though it’s only ⅛ of an inch thick as a layer on the surface of your concrete block wall.
2. It Can be Further Waterproofed
As we mentioned above, when you need to maximize protection against water, as you might in a basement, for example, then Semco’s natural protection can be augmented with Semco’s own Liquid Membrane which goes beneath the micro cement layers. The level of protection is such that you could turn your basement into a giant bathtub if you really wanted!
3. It Has an Integral Color and Finish
Finally, once Semco is applied, it adds its own integral color and finishes to the wall so you needn’t take any further action if you don’t want to. This finish is used in the homes of movie directors, fashion designers, athletes, and more. If you did want to paint on top of Semco, you can easily paint the surface and color without losing any of Semco’s inherent benefits. Semco can be pigmented in any color in either solid or variegated colors. The Semco will still be as durable as ever.

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Since 1991
Concrete & Tile Resurfacing Solutions
SEMCO Florida, Innovation driven surface engineering company that specializes in developing surfacing products for floors, walls, pool decks and waterproofing.