Not everybody wants a "house of concrete walls," but modern architects increasingly embrace exposed concrete feature walls, both as part of the architectural and interior design of the building.
Board-formed concrete walls are almost exclusively the domain of new construction and high-end remodel projects, mainly due to their complexity and impact on the construction schedule. An excellent alternative, with broad design and functional varieties, is microcement. From a design standpoint, you will get a concrete-like look on a standard wood-framed wall, so it is a perfectly viable option for ambitious homeowners embarking on a significant home renovation. From a functional perspective, you'll have a standard wall that can hide electrical and mechanical runs, something nearly impossible with exposed concrete walls.
Microcement's increasing popularity in high-end residential and commercial projects is unsurprising. With an extensive color range and finish appearance, microcement lets designers, architects, and homeowners give any interior space a sleek, minimalist, and contemporary look. With proper application, which we will cover later in this article, a wall finished in microcement resists abrasions and scratches, making it perfect for high-traffic areas such as hallways without compromising aesthetics.
In our interior design projects here at Angelbau, we increasingly see conditions where our Fortius concealed doors get coated with a layer of concrete micro-topping and blend in with a microcement-clad wall.
Several manufacturers offer microcement in North America, with many of the latest product iterations being marketed as environmentally friendly and VOC-free. Consult your contractor to see which brand they prefer and why.
Microcement, frequently called micro concrete, microtopping, micro-screed, or micro-overlay, is a versatile cementitious coating that creates a concrete wall or concrete-style surface effect.
You can apply microcement as a thin material layer (usually 2-3 mm, equivalent to ~3/32" to 4/32") on almost any substrate, such as tiles, parquet, natural stone, drywall, OSB panels, metal, marble, ceramics, and even MDF solid core frameless doors.
Microcement primarily consists of cement, fine sand, water-based liquid polymers or powdered resin polymers, and pigments. These ingredients are blended to produce a consistent paste, which the installer applies in a 2-4 layer process. The basic microcement layering schema consists of a primer, two microcement layers, and a varnish/sealer layer.
Even though micro-topping layers are relatively thin, for flush-with-the-wall concealed doors, flush baseboards, and similar modern filomuro details, as a designer you should always specify the use of microcement in the Construction Documents to ensure that the thin layer aligns with other finishes perfectly once the project reaches the Construction Administration phase.
Depending on how you apply microcement with stainless steel and plastic trowels, you can achieve either a textured or a smooth wall finish, a desirable value proposition for interior designers.
To achieve a long-lasting quality finish, you should be familiar with the steps required for the microcement application process, even if you outsource the work to others. The steps will vary based on the manufacturer (Topcret, Epodex, Surecrete), specific microcement composition (standard, eco-friendly), and the application (indoor walls, outdoor walls, floors, wet areas).
Let's review our microcement step-by-step guide for a typical indoor wall and Dorsis Fortius door panel application.
Before applying microcement on the wall, repair any visible damage or imperfections:
The wall must be clean, dry, and free of contaminants such as oil stains, grease, or solvent paint that prevent primer adhesion.
A bonding primer will create a strong base for microcement and prevent imperfections from bleeding through. There are primers for absorbent surfaces, primers for non-absorbent surfaces, and fillers — all designed as adhesion promoters.
Standard drywall/sheetrock boards, concrete, masonry, or wood substrates are porous, so in a typical construction with sheetrock walls and Fortius concealed door panels, use primers for absorbent surfaces.
Depending on your brand, some primers can be colored to match the color of the final microcement layer.
You will apply the bonding primer not just on the door slab itself but also on the flush side of the Dorsis Fortius hidden door frame.
Mix the microcement with water and, if available, any desired pigments to achieve the preferred color or shade.
Apply the microcement to the surface in a thin layer, leaving it to dry before you apply the second layer. Microcement dries slowly: for example, Epodex recommends an 8-24 hour waiting time between layers.
Ensure the first microcement layer is dry. Apply a second layer of microcement to the wall and Dorsis Fortius door surfaces. The second microcement layer should be slightly thicker than the first, creating the desired texture and finish.
Seal the surface with a sealer to protect the surface from stains and water damage. Apply the sealer (often a mix of matte PU resin and hardener) thinly in a crosswise motion and allow it to cure. Check the microtopping manufacturer's instructions to see if they recommend one or two coats. Most microcement compounds need about 3-4 weeks to achieve full hardness at room temperature and humidity (68ºF/20ºC and 40-60% of relative humidity).
