Preparing Surfaces For Microcement

The following guidelines are for the attention of main contractors, builders, architects and clients who are responsible for preparing/specifying surfaces for microcement.  Please read them carefully as early in the build as possible. To see more background see our Microcement guide.

Well Consolidated

The surface should be well consolidated, so that no further settlement or movement is anticipated.  As with tiling, movement in the sub floor will cause cracks to appear in the surface.

Cracks in the microcement due to unconsolidated surfaces are the responsibility of the contractor who laid the sub floor not the applicator of the microcement.

Whilst microcement is very hard, it should be considered as a topping compound only.  It is the responsibility contractor who laid the substrate that the materials used are fit for purpose.

We can fill cracks and gaps that have appeared in the surface during settlement of less that 5mm wide.  Cracks that are larger than 5mm must be filled by the contractor who laid the floor in advance of microcement installations taking place.

Subfloors must be dried in accordance with manufacturers recommendations and underfloor heating should have completed a full cycle in advance of installation.

Cold Joints & Expansion Joints

Wherever 2 separate subfloors meet, whether they have been laid at different times or have intentional expansion joints in them, movement is most likely to occur along the join. Whilst we take every care to fill and mesh the joints, if there is movement in the subfloors, this may cause the microcement to crack.

In order to prevent cracks in the microcement caused by cold joints, concrete & screed subfloors should be poured in one complete pour wherever possible. Or we can insert a bead or threshold to separate the 2 surfaces and microcement up to the bead on either side.

Level Surfaces

Floors must be level to within 3mm tolerance maximum.  Floors that are not level will need to be levelled off with a self-leveller and appropriate acrylic primer. Please leave 4mm to finished floor height for microcement.

Microcement can be laid onto a wide range of surfaces, including concrete, screeds, cement board, ceramic, plasterboard, ply board, chip board & mdf.  It cannot be applied directly onto timber which is at risk of warping.  And it cannot be applied over voids between adjoining surfaces.

Timber floor boards will need to be covered with a suitable cement board. These should be sufficiently fixed to the joists so that no further movement is possible.  They should also be butted up against one another with silicone squeezed between the joints leaving excess to dry so that it can be cut cleanly off.

Construction boards should be glued and screwed in place to create a stable base for the microcement.

Less than 5% Moisture Content

All surfaces will need to have less than 5% moisture content when we come to install.  We can test the moisture content on arrival, but please work to the manufacturer’s recommended drying times for freshly laid surfaces.  If surfaces are not dry when we arrive on site, extra costs and/or delays to the build will be incurred.

Water Tight

The area must be completely water tight and free from risk of rain water, spills or leaks.

Until sealed, the microcement will be very porous so any water that makes contact with the surface will stain. Anyone who spills water on the surface must take responsibility for the cost of repairs.

Access

The area will need to be completely clear, with no access to other trades for the time it takes the installer to complete the work (usually 6 days).

Skirting Boards & Perimeters

We would prefer that skirting boards & kick boards are removed/left off prior to work commencing.

We will tape up the perimeter of the areas to be microcemented to ensure a clean finish but we cannot guarantee that paint won't be lifted off surfaces when we remove the tape at the end of the job.  We take no responsibility for repainting walls or skirting boards, so would advise that painting is completed after microcement work has taken place.

Curing Times

The microcement will not be fully cured until 4 weeks after it has been laid.  Please take care not to scratch, cut, drop or drag items on the floor during this time.  The cost of repairing any damage caused will need to be paid by those responsible.

Once cured, microcement is strong, anti-slip and has a good resistance to stains.  You can treat it as you would a hard wood floor.

Underfloor Heating

Underfloor heating must have completed a full cycle prior to microcement being applied. This will force cracks to appear in advance, reducing the likelihood of them appearing post-installation.

Please ensure underfloor heating is turned off 48 hours before work is due to start & keep it off for the duration of the work.

After applying the microcement, at least 48 hours should pass before the heating is gradually turned on (+5°C each day).

Maintain the water entering the circuits at 25°C throughout 2 or 3 days. Then gradually increase the water temperature to 45°C and keep it on for several days.

Always change the temperature gradually, both at the beginning and at the end of the heating period.

Ensure the heating is turned on within 4 weeks of us laying the floor.

Make sure that the relative air humidity in the rooms is not too low.

Always avoid an accumulation of heat caused by rugs and carpets, or the lack of space between the furniture and the floor.

Showers & Wet Rooms

Prior to microcementing, shower areas and wet room floors must be covered in fit for purpose shower trays & flooring which will not be susceptible to movement.  These should be fitted as per the manufacturer’s recommendations.  Please ensure that they are sufficiently fixed to ensure no further movement can occur.

Wherever possible, please use Marmox Showerstone Trays for Vinyl floors as these are resistant to movement and have 3mm sides unlike those made for tiles.

Water resistant plaster boards should be fixed to walls and run right down to the floor.  Please firmly fix the boards to the floor at joints with the floors or shower tray. We ask that the walls are plastered to ensure the surface is level.

Microcement will create a completely waterproof surface but it can only be applied to existing surfaces.  We will only microcement onto what is there, gaps or voids cannot be seamlessly filled after installation has taken place.  It is the client's responsibility to ensure that cut outs for fixtures and fittings are accurately cut so that there are no gaps between the fittings an the wall or in any other area intended for microcement.

Gaps & Voids in Substrates

Because microcement is a seamless product, it cannot be patched in.  If areas are missed because there are gaps or voids in the substrate, or if fixtures are moved post-install; the entire wall / floor will need to be recoated & resealed.  And we will charge the client for both materials and labour time to rectify.

We ask that clients take there time to clearly communicate the areas that they want covering in detail during site visits.

Fixing to Surfaces after Microcement is Installed

Microcement can be drilled and screw into using drill bits that are suitable for the substrate.

Because it is the sealers that make microcement waterproof, any holes or cuts will need protecting from moisture penetration by either putting silicone into screw holes or by surrounding fixtures & fitting entirely with silicone.  Care must also be taken not to scratch the sealers whilst installing fixtures & fittings.

Caring for Microcement Surfaces

First 7 Days

Like all concrete, microcement takes 28 days to full harden.  It’s at it’s softest for the first 7 days after laying.  During this time it should only be subjected to light use and light foot traffic.

Any heavy work is not recommended, but if it does take place then we recommend that you cover the floor with a breathable material or only cover down whilst working & lift the protection off for the majority of the time.  The surface needs to dry out and harden.  If not enough air gets to it, it will stain & not cure correctly.

Hardness

Despite its lack of thickness, one of this material’s most significant properties is its high resistance and hardness; Microdeck and Microstone can even be used in areas of high traffic.

Several factors influence the resistance and hardness of microcement, such as the support on which it is applied, the type of microcement chosen, as well as the sealant used on the finished microcement.

We can differentiate between two types of resistance:

Mechanical Resistance

To blows: Microcement, due to its limited thickness, will deform in the event of a strong blow if the support beneath deforms. An example would be the microcement applied to plaster. If the base deforms because it has poor resistance, the microcement will deform as well. While on a support like terrazzo, the resistance will be greater.

To abrasion and wear: This resistance depends on both the microcement type and the sealant. Topciment has two seamless floor coverings: Microdeck and Microstone. Both are coatings with selected aggregates of a larger particle size than that of Microfino, which makes them more resistant to compression and abrasion. Microfino, due to its lower strength, is used exclusively for wall covering. As for sealants, although the resistance is the same, the higher the gloss, the more visible the marks of wear. Matte finishes do not reflect the light, or do so only minimally.

Chemical Resistance

To stains and liquids: The chemical resistance will depend on the sealant used to protect the product. The sealant is the final layer, which is what gives the product protection and impermeability against stains. Our Topsealer sealants have a high chemical resistance, confirmed by the various tests conducted: Oil, cola, red wine and similar. Do not leave stains to soak in.

Both vinegar or lemon juice leave slight marks on microcement. These acids affect the surface as they would on marble, but if cleaning is done quickly, there will be no stains.

The spots of Salfuman / hydrochloric acid, pure bleach, acetone and ammonia will mark after a half hour of exposure, but if cleaning is done quickly, no stains will remain. It is important to consider microcement’s texture and the difficulty of cleaning.

Cleaning 

To ensure the long and durable life of our microcements, we recommend the use of water and neutral soaps.

The care of microcement is similar to that of natural wood parquet. We advise to avoid permanent wetness, or prolonged contact with moisture. Leaving wet carpets and towels on the floor is ill-advised, as are pots that leak. The surfaces should also be kept free of stones or grit which can scratch the coating. Avoid any blows and rubbing with hard objects.

Although microcement offers a high resistance to chemicals, cleaning should be done with neutral soaps, never with aggressive or descaling products. Additionally, avoid products such as chlorine, bleach, ammonia, soaps and detergents in general, as they can damage the protective film.

Initial Care

Microcement reaches its desired values of hardness and chemical resistance one month after applying the sealer. Therefore, being very careful during the first weeks is very important, because it is when microcement it is more likely to suffer some damages. It is gently accessible two days after applying the sealer. After one week, it can be accessed normally. Do not cover the surface during the first weeks. For example: do not hang paintings or put carpets.

Dragging heavy objects over the surface is not recommended, as damage could occur. To move furniture: it is advisable to lift and support, never to drag. It is necessary to protect flooring, with lids or felts, from the pressure points of furniture (metal feet, sharp surfaces), or objects with abrasive or heavy contact surfaces.

Special Care

With the aim of not damaging the surface it is very important avoiding shock and friction with hard objects, as well as moving furniture (remember lift and drop, never drag). It is necessary to protect the floor from furniture which can damage the surface, like for example metal legs or sharp surfaces. Furniture legs must be of soft rubber which are less aggressive.

Daily Maintenance

For cleaning the microcement, the most recommendable is using the products specially created for it: Ecoclean and Ecoclean Pro. Ecoclean: Ecological household cleaner. It’s a very concentrated product and suitable for the cleaning of microcement. Dilute in water for its application.

Important: wait at least two weeks after applying the varnish to ensure its correct curing and thus avoid damaging it.

Ecoclean Pro: Professional and eco-friendly cleaner, especially suitable for cleaning difficult and persistent dirt. This cleaner is not diluted in water, it is sprayed and needs a few minutes to start acting.

Other possibility is using PH neutral soaps, never harsh products.

Ammonia, chlorine, bleach and non PH neutral soaps and detergents must be avoided. Never let the soap too long on the microcement to avoid damaging its protective layer.

Do not leave liquids including water, oil, coffee spills on the surface for over 4 hours or wine, vinegar & bleach for over 2 hours.  Avoid all contact with acetone as it will breakdown the sealers almost immediately.

Periodic Maintenance 

We recommend to do a periodic maintenance of microcement with an acrylic wax that leaves a protective layer. Ceraciment is a composite that provides persistent hardness and natural brightness. The frequency of maintenance depends on the daily use and characteristics of the floor.

Instructions for Ceraciment Wax

Add a small dose in water: 20-25 mL per every 7 litres of water (hand application with sponge, mop) 25-100 mL per every 10 litres of water (application with machine)

Apply one coat of CERACIMENT on the microcement surface already sealed, cured and completely clean. Keep in mind that the wax treatment is not permanent, it is necessary to repeat the process from time to time.

Important: before applying the wax treatment, wait at least two weeks after installation is complete, to ensure its correct curing and thus avoid damaging it.

Contains: 1,2-benzisothiazol-(2H)-one,1,2-benzisothiazolin-3-one.

Waterproof

Microcement in itself is not impermeable. The use of a sealer as a final coating, which will ensure a water-proof capability is absolutely essential. Therefore microcement may be applied to sinks, bathtubs or wet areas, but the surface must always be sealed by our installers to ensure it is impermeable.

Please contact us if water begins to stain surfaces, even temporarily as this may mean that a re-seal is required.

Any Questions?

Please feel free to get in touch. 07487 247 388 | info@relentlessinteriors.com