How to properly make imprinted concrete
Imprinted concrete, also called stamped concrete, is a decorative technique thanks to which any surface can be customised in an unlimited way. With it, you can quickly and easily mimic the appearance of noble materials such as cobblestones, brick, stone, tiles, slate or wood, among many others.
A most versatile material that we frequently find in public areas such as sidewalks, roads, squares, parks or shopping centres. But it is also very common to find it in porches, terraces and entrances to residential areas. Generally outdoors, but lately the use of imprinted concrete indoors is gaining strength. Especially in imprinted pavements of large warehouses and spaces such as car parks, sports centres, hotels, shopping centres and restaurants.
But, how is imprinted concrete made? The first thing you need to know is that the application method varies depending on the surface where you want to apply this coating. In this sense, the treatment on floors and walls is not the same, although the final results are equally spectacular.
Next, we explain how to make imprinted concrete on floors and pavements and, also, how to apply vertical imprinted concrete on walls, facades and walls.
How to make imprinted concrete on floors: step by step application
The use of imprinted concrete on floors, both indoors and outdoors, is the most common use of this coating. Some of the most striking imprinted pavements can be found in parks, terraces, squares, outdoor car parks, exteriors of shopping centres or entrances to residential areas.
In this section we explain how imprinted concrete is made on floors and pavements, step by step, to ensure success in the work. Making a mistake in any of the steps can be fatal.
1. Prepare the pavement before pouring concrete
It is essential that the ground on which the fresh concrete is to be poured is in perfect condition, as it directly affects both the behaviour and durability of the future imprinted pavement. To do this, the surface must be cleared of any element that could be an obstacle such as leaves or stones. Only in this way will a clean and quality surface be guaranteed.
To ensure the planimetry of the imprinted concrete pavement, the levels and slopes of the ground must be prepared. A film of 400 gauge policret sheet will be applied to the base to prevent the dehydration of the concrete and a perimeter joint will be placed to delimit the areas to be filled with the concrete by placing a formwork box.
Before applying the concrete on the pavement, it is essential to pour the gravel (15 cm) and the sand (2 cm) and compact the support.
2. Pour the concrete on the ground
Once the support is prepared, it's time to pour the concrete evenly to prevent future problems. The layer of concrete must be perfectly levelled and compacted. Add polypropylene fibres to the concrete to improve its strength. A steel mesh and joint should also be used on all perimeters and encounters with fixed elements.
If any of the following cases occur, the pouring of concrete on the floor or pavement must be interrupted:
If a possible drop in temperatures, below 0ºC, is forecasted during the first 48 hours.
If the temperature of the concrete is below 10ºC or if the ambient temperature exceeds 30ºC.
If there is excessive wind. A condition that can cause the surface to dry out.
3. Levelling and screeding of the concrete applied on the ground
Use a roller to compact and bleed the concrete. For the smoothing or levelling of the concrete floor, a trowel or leveller must be used. To make imprinted concrete correctly, it is essential that there is no mechanical vibration in the screeding.
4. Trowelling of the concrete
With the concrete still fresh, carry out the trowelling to obtain a uniform, compact, resistant, smooth and durable pavement. Skipping this step could cause the appearance of blisters and lamination due to excess moisture.
5A . Sprinkle the coloured hardener or imprinted mortar on the pavement
Once the exudation water has evaporated from the concrete, sprinkle the corresponding colour hardener or imprinted mortar on the pavement. In our case, Stonecem® Floor with a proportion from 4 Kg/m² for dark colours up to 6 Kg/m² for light colours.
To make imprinted concrete on floors, it is very important to sprinkle the right amount of product. Otherwise, the result of the imprinted concrete floor will not be as desired.
5B. Colouring of bulk concrete
In addition to dusting, which is the traditional technique for pigmenting concrete pavement, another system is to use a pigment in powder form as Arcocem® Fast. This method consists of introducing two bags into the concrete mixer for each cubic meter of surface to cover. We leave it for five minutes for the product to mix with the concrete until a homogeneous and uniform mass is achieved. Once it's ready, the concrete would be poured onto the support.
6. Trowel the colour hardener or imprinted mortar applied on the floor
Apply 2/3 of the specified amount of colour hardener or imprinted mortar Stonecem® Floor and introduce the material into the concrete using a standardised trowel. Then, apply the rest of the product and proceed to trowel again until the desired finish is achieved.
7. Smooth the future imprinted pavement
The surface must be completely smoothed and without irregularities. To do this, use a steel trowel until it is guaranteed that the surface has no porosity and is totally homogeneous. Go over the edges of the concrete pavement with an edging trowel, to avoid chipping.
8. Apply the release agent for imprinted concrete on the pavement
Once the mortar has set, ensure that the future imprinted pavement has a firm but not hard appearance. And, above all, that the surface is free of water. Once checked, apply the chosen release agent for imprinted concrete.
Within the Desmocem® family, we have powder release agents (Desmocem® Powder) and release agents for liquid imprinted concrete (Desmocem® Liquid). We advise using the first one, except in interior spaces.
It should be noted that the release agent for imprinted concrete in powder Desmocem® Powder it carries colour that, can be of the same shade as the colour hardener, or different if an aged effect is sought. Both favour the extraction of the imprinted concrete mould once stamped on the pavement. The proportions are: 100 gr/m² and 125 mL/m² respectively.
9. Prime the stamped concrete mould on the floor
To execute the imprinted concrete on the ground it is essential to choose a mould and stamp it on the surface. Without this element, we would be talking about a different decorative technique. In Imacem, we have over 150 types to impregnate the ground in a certain way.
Once the imprinted concrete mould has been selected, stamp it onto the surface to imprint it. The placement of the mould on the ground must be consecutive and follow the continuity of the pieces. Use a tamper to more easily achieve the engraving of it.
Once done, we will proceed to carefully remove the mould from the pavement and place it on the rest of the untreated surface of the imprinted concrete floor. It is very important to respect the created design for the result to be optimal.
10. Remove the release agent for imprinted concrete from the pavement
If the expansion joints have not been initially planned, make the cuts according to the project and before 24 hours from its implementation. At least 48 hours later, proceed to remove the release agent for imprinted concrete from the pavement.
11. Clean the imprinted pavement
72 hours later, rinse the treated surface with water to remove any product residue and let it dry. To clean the imprinted pavement, a pressure washer can be used with an approximate pressure of 90 bars, applying the water gun at a prudent distance of 50 centimetres and nozzle in fan position.
Never, under any circumstances, apply a direct jet of water on the surface. In case the release agent for imprinted concrete used is Desmocem® Liquid, clean the imprinted pavement by sweeping.
We recommend using our cleaners Ecoclean Pro or Ecoclean Construction. This last one is very useful to prevent efflorescence after use of Desmocem® Powder. A detergent that removes lime, saltpetre, grouts, cement residues, etc. After its application, let the product act between 5 and 15 minutes. Once the time has passed, rinse the imprinted pavement with water and let it dry.
12. Apply the varnish to protect the imprinted pavement
The last step to make imprinted concrete on floors is without a doubt one of the most important. As only good protection can ensure the durability and good condition of the pavement. At Topciment we have developed the family of varnishes Sealcem®, where there are water-based varnishes and solvent-based varnishes. The choice of one type or another depends on the shine and finish that is sought.
Once the imprinted pavement has dried, apply two coats of any of our varnishes from the family Sealcem® . Do it by airless, brush or roller and let it dry. Although our varnishes have excellent resistance to weather, and therefore, to different weather conditions such as water, wind and sun; we recommend renewing the varnish.