Stamped concrete: What it is, molds, colors, cost. How to do It?

Pavement and stamped concrete

Within the wide range of construction possibilities in which concrete and its different applications come into play, there is stamped concrete (also commonly called imprited pavement and erroneously assigned with the name of “imprinted cement” when they are different concepts).

To understand printed concrete; what it is, what it is used for, types, colors, where it is placed or why it is used. First we have to review what concrete is.

The printed pavement, is a construction material where different elements are combined; a binder (which is usually Portland cement), aggregates (sand, gravel, gravel, etc), water and some specific additives (See examples of houses with concrete).

When combining them, according to proportions and properties, we have a constructive material with certain benefits, which, in addition, in general, is malleable, has adherent characteristics and is of great hardness.

From here, an aesthetic alternative to the traditional decorative architectural materials used in exterior flooring such as wood, ceramic, terrazzo, etc., appears. New techniques and construction systems that represent imitations of noble materials.

The use of fair-faced concrete for exterior paving has its particularities and this is what we are going to discover in detail…

What is stamped concrete?

Printed concrete pavement is defined as the decorative technique that results from applying a continuous hardening mortar made in situ, usually with color, on a fresh concrete surface. The subsequent texturing, embossing, stamping, are with molds of different shapes and designs, and the application of the final product and protection (which is a resin).

Some examples of stamped concrete with different finishes:

The resulting hardened mortar will give us similar appearance to noble materials such as slate, stone, slate, cobblestone, ceramic tiles, wood or, practically, any other with varied geometric shapes (See also types of laminate flooring and which is better).

To understand the stamping in particular from a schematic perspective, we leave the two most general cases with their main layers; when we have no base and with base – screed on consolidated soil.

It is not a new covering mortar, it already has years of baggage, and it is a material par excellence in floors of many public places; in walkways, sidewalks, roads, streets, squares, urbanizations, etc.

Its usefulness has also been transferred to the exterior of buildings, in their common areas, or especially in single-family homes (villas) as a coating for terraces, porches, paths, in short, outdoor areas or the edges of swimming pools (in the latter, care must be taken because of the ph – chlorine in the pool).

Although it has some advantages, it must be said that it will never bring us the true aesthetics of a noble material such as stone or wood, or the possible perfectionist finishes of a good ceramic tile or prefabricated terrazzo, it must be taken into account!

Printed concrete, although it has favorable aspects, will never provide us with the aesthetic beauty of a noble material or the perfectionist finishes of prefabricated slabs.

Pigmented concrete in which a grid is engraved while fresh that simulates pieces and textures of other materials. It requires quite technical specifications in cases of heavy traffic or special laying (there is a guide to this effect below).

Templates and molds

The market offers for sale a great variety of grids, flat templates with relief and molds (metallic – polyurethane) with different solutions, dimensions and thickness; small, large, rectangular, oval, arched, herringbone, etc, which are obviously symmetrical and we can replicate them to our liking. The most common types of molds for printed concrete are:

• Mold imitating paving stones
• Imitation stone molds
• Imitation tile mold
• Imitation border mold
• Imitation wood mold

Image above represents polyurethane stencils that are much less heavy and easy to use when printing a texture to look like imitations. There are also solutions with reliefs like the following image or rougher ones with a border to simulate stones on a road.

Pigmentation in cements and concretes

Some professionals call “colorant” (soluble substance) the product that colors the mortar when we practice stamped concrete, but, in fact, the technical description is pigment (insoluble substance).

There is a wide range of products for coloring cement and concrete, which in turn brings a complexity when it comes to obtaining a certain color (see article color in architecture). It is always necessary to make previous tests to see the final result or we can take a good scare and not obtain the color that the client wishes.

It is always necessary to make previous color tests to see the final result.

Pigments can be natural or artificial. They usually range in color from organic greens, blues, yellows and reds, ideal for interiors, to blacks, reds, yellows, grays, browns, greens and inorganic blues for exteriors.

Organic pigments are not stable because of their higher reactivity at times (high resistance to alkalis is needed – cement and lime are alkaline in nature), because of their small particle size, resistance to solar radiation or their low resistance to weathering.

For stamped floors in construction and construction, the artificial – inorganic ones are normally used and within this palette, the most recommended are the synthetic iron oxides.

To color the cementitious products that we will use in exterior we have limitations that mark us the different tonalities of the pigments that we can use(Technical guide here also have a calculator of the pigment to use). In the following image we have the palette of synthetic colors that we can use:

Advantages and disadvantages of printed concrete

There is no work or construction element that is perfect and in most cases, the economic investment (paying more or less, both in the work of the operators and in the materials) largely determines the useful life of the work carried out.

Advantages

• Multiple designs. The possibilities of geometric patterns in a printed floor, textures and colors in the finishes are practically infinite. There are even some companies that can create patterns according to customer needs, which obviously increases the price of execution.
• Fast execution. The laying of mortar in situ, because it is continuous, is usually faster than laid paving. An important advantage in the architectural sector and it is necessary to be careful with the geometric forms, the more complex, the longer the execution time, and, therefore, the higher the final price.
• Lower price compared to traditional materials. On average, the price per square meter is usually lower when compared to pavers of average quality.
• Prevents weed growth. Forming a larger “slab” style paving prevents weeds from growing through it. Two frustrating factors in an outdoor paved space are weeds growing through the joints and water washing away material and creating crooked, swaying slabs.

• Low maintenance requirements. No special care is required once executed, but an impeccable laying is required if we do not want to have problems throughout its useful life (if there is enough wear due to cars or for any other reason, a new sealing layer will be needed).
• Long service life. The printed concrete has a great resistance and durability to the atmospheric conditions and therefore, a longer useful life than many other materials used in exterior.
• Punctual breakage. A possible forceful blow on the floor is focused in only one point, in the pavers, in many cases we would see it broken in two.

Disadvantages

• Expert workmanship is required. Although apparently its execution is simple, if we want durability, it is necessary to follow some concrete steps respecting the time of setting – hardening, application of release agent, pigments, etc. Directly to hire a professional.
• Costly repairs. When we have a bad execution or some punctual problem, it is difficult and with high cost to patch or repair the stamped concrete. In addition, if we have a badly stamped, chipped or colored section, if we proceed to trimming, replacement – polishing, there will usually be an obvious difference to the original surface.
• Be careful with the release agent and sealer. Old and poorly preserved products can cause premature surface wear, flaking, different shades, etc.
• Cracks. As they are executed continuously and form larger slabs, it is necessary to pay special attention to the expansion joints. A lack of them, we can have problems in random cracking of the surface.

• Not suitable for extreme environments. With the expansions and contractions that concrete undergoes, it is not always the best option in places with extreme climatic changes.
• Beware of drainage. Although we have expansion joints, there may be future problems with water drainage.
• Beware of hidden elements. It is necessary to take care that there are no pipes or other elements of importance buried, it would take us a not pleasant and expensive repair.

What is the price of printed concrete?

Actually, here we can spend hours discussing. A wide market with multiple companies specialized in its placement and without taking into account the customer’s requirements or budget, surface or accessibility.

It is necessary to ask for several budgets, always with contract and well detailed with technical specifications.

What we do have clear is that the budget of the printed pavements must be per square meter executed (labor and materials) and finished (in the case of curbs, it is usually budgeted per linear meter).

In order to make a comparison within a coherent reality we have turned to the Base of Construction Prices published by the IVE for this year. The average price of printed concrete is around 41 Euros per square meter including labor, thickness of 14 centimeters, mesh and polypropylene fibers.

There are cases that will offer us with thickness of 10 cm, instead of the 14 cm indicated in the image. It is very convenient to use a mesh – reinforcement. Do not use printed concrete without reinforcement! (Further on we explain)

Remember that we wrote an article about a tool of the IVE on how to pre-calculate costs for urban works.

How is printed concrete made?

Although the execution process of the printed concrete is relatively fast, obviously, we will have to follow some steps and control the times, both for an adequate adherence and a homogeneity in the color.

From a technical perspective, concrete floors and the choice of the same requires professional knowledge and this reference guide (Free PDF download, if we register) on continuous pavements with concrete (Applies Spanish regulations) will help us to make the right choice according to road and other important technical aspects.

Given the great diversity of solutions and finishes, with joints that can respond to the same service situation, an identification code is defined that is indicative of the characteristics of the same directly related to the use to which it will be subjected.

Now, we leave an infographic from the manufacturer Sika to see step by step the in situ installation procedure in a general way:

As we want to make clear the process to make a printed concrete floor, first we leave a video of the complete process in situ, including the screed (base):

The summary for the procedure to make reinforced concrete and decorative pavement step by step with our experience is:

• Preparation of the area.

  • Delimit the area with curbs (not shown in the video).
  • Pour a cleaning layer of concrete about 5 centimeters above the ground.
• Placing the mesh
  • Lay the mesh over the cleaning layer.
• Concreting the screed
  • Pour the concrete, keeping it soft.
  • Spread the concrete with a rake to facilitate the use of the screed.
  • Compact and lightly vibrate the concrete to obtain a homogeneous surface.
• Leveling the screed
  • Pass the straightedge over the screed, using a row of stones as a reference.
  • Remove the excess concrete until the desired level is obtained.
• Application of the wearing course
  • Sprinkle the wearing course with powder, creating a film of a few millimeters.
  • Wait for the powder to absorb water from the concrete and change to a dark gray color.
  • Work the surface with a steel trowel to fuse the powder with the concrete.
• Application of the release agent and molding
  • Sprinkle release agent on the surface, using approximately 5 kilograms per square meter.
  • Place the molds on the concrete, stepping on them to shape them.
  • Continue placing and removing the molds as the surface progresses.
• Cleaning and sealing
  • Allow the concrete to dry for 24 hours.
  • Sweep and remove the release agent dust.
  • Clean the surface with a pressure washer and allow to dry.
• Resin application
  • Mix resin with solvent (8 liters of resin per 1 liter of solvent).
  • Apply two coats of resin with a roller, ensuring a uniform application.

• Final result

  • Observe the decorative finish, the impermeability and the hardness of the pavement.

And to see it from a more technical visual perspective, we leave a fairly detailed video of the system and execution process of printed concrete with some useful tips:

With the right tools the installation will not be a problem in the hands of specialists. The paving is manufactured directly on site and continuously. It is not limited to installation on sloping or uneven floors, where other materials would not be suitable (Of interest is the article on mosaic floors and hydraulic tiles).

It is necessary to calculate well the panel to execute so that plasticity is not lost, working in short sections is better.

Shrinkage joints in continuous concrete slabs are very important. Their function is to limit the stresses produced by shrinkage phenomena and by thermal gradients, with them, we will avoid many problems of cracks and breaks:

• The ratio between the lengths of the longest and shortest sides should not exceed 1.5.
• In non-rectangular or square slabs, angles < 60º should be avoided.
• If the pavement is constructed in strips, staggered joints should be avoided.

In addition, we would like to add some useful tips from Pavistamp in their material sales guide on setting colored mortar for stamped concrete, powdered release agent (Prevents the mortar from sticking to the mold) and on protective resin:

Mesh or fibers in printed pavement?

For the reinforcement and improvement of the different characteristics of the concrete pavement, it is used the mesh (grid made of metallic materials) or steel fibers (there are also other materials, for example, macrosynthetic fibers).

Although each professional has his own opinion, we provide the following diagram comparing the mesh with the fiber of the company Obralia:

We find the contribution of fibers on concrete and its advantages quite interesting. Although it must be emphasized that there is an important range of fibers and you should always consult professionals to choose the most coherent according to your needs.

In one article it is impossible to detail all the systems and technical aspects of the wide world of printed concrete, the varieties of materials and the different types of installation with different punctualities. We have only wanted to give a general overview that can provide value.

This technique has been used for a long time and therefore, there is a lot of experience in the market. The best advice is to look for different budgets and always in companies that have demonstrable projects and that we can test.

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