Screed mortar for low thickness stamped screeds

As mentioned above, a screed is used when a stamped concrete floor of less than 10 centimetres is to be made. Either because of taste and aesthetic preferences or because there is not enough height to apply a thicker stamped mortar.

It is important to underline that a screed mortar can be used both to renovate and rehabilitate an existing floor, as well as to build a new one. In the case of an old concrete substrate, if for whatever reason the screed cannot be applied, the soil must be compacted and raised to the desired height so that the product can then be applied.

In addition, Topciment® Overlay is equally suitable for indoor and outdoor use and resists freeze-thaw cycles to perfection.

The system for making traditional stamped concrete, i.e. with a stamped mortar or screed, does not differ much from the process of applying a screed.

It is essential to clean and prime the substrate properly.

Make expansion joints and the relevant cuts.

Apply the appropriate bonding bridge to the substrate.

Use a good release agent, stamp the flooring with the chosen mould and seal it with a high-performance varnish.

ImportantMix the screed mortar with a mixer or concrete mixer and mix it with water and polymer, if it is not included in the product. Topciment® Overlay already incorporates the polymer, so it is only necessary to add water to the mixture.

Depending on the formulation of the screed mortar and the manufacturer's instructions, the mixtures will be different. As a general rule, the recommended proportion of water can be between 12% and 20% of the mortar. In the summer season, in cities and countries where it is very hot, the amount of water required may be higher. In Topciment® Overlay the ratio is 5L of water to 25 Kg of mortar.

The following are the most common problems that can and do occur when applying a screed. Mistakes to avoid at all costs to avoid major mishaps over time.

1. Forgetting about expansion joints

It may seem obvious, but in more projects than you might think, something as basic as making the expansion joints is not done with the accuracy that a printed flooring requires. A mistake that is more common than we would like and which causes the printed concrete to end up cracking due to unwanted cracks caused by the pressures caused by temperature changes and/or seismic movements. Especially on surfaces that are heavily trafficked by heavy vehicles.

2. No perimeter joints

Perimeter joints represent the separation of the surfacing from structural elements of the pavement. Their main function is to ensure that the mobility of the surfacing is not compromised. Therefore, the perimeter joints must be placed in all the joints of the stamped concrete floor that is going to be made with the screed mortar. If this is not done, cracks will appear sooner or later in the screed.

3. Not respecting the mixing ratio of the screed mortar

The importance of strictly following the manufacturer's instructions on the mixing and mixing of the screed mortar has already been detailed above. If this is not the case, not only will the consistency of the product be altered, but also the drying times and, more importantly and seriously, the mechanical resistance will decrease. The lower the performance, the lower the quality and guarantee of the product.

4. Not taking into account the unevenness of the pavement

Special attention must be paid to the unevenness of the surface so that it does not exceed 15%. If this figure is exceeded, we will find more than palpable differences in the thickness of the slopes of the stamped concrete floor. An unevenness that would crack the paving.

Like any product, the cost of screed does not depend on a single element, but is subject to several factors that determine its value. The quality of the screed mortar, the labour and dimensions of the flooring to be renovated, as well as the thickness of the product itself are just some of them.

Not only can it be done, but it is also an excellent solution. Screed mortar promotes optimal heat transfer from the underfloor heating to the room or area in which it is located. But not only that, it also minimises possible heat loss to the layers below. An advantage to which we must add the lower energy costs and, therefore, the economic savings over time.

The only thing is that a protocol for switching on the underfloor heating must be followed to avoid shrinkage cracks. Therefore, the screed mortar must be applied with precision on an underfloor heating system and the temperature must be gradually increased.