Many of our customers come to us because their floor is in poor condition, due to defects or because the concrete has been badly trowelled.
There are many reasons for this: because the concrete has too much water in it, because it has dried too quickly and has not had time to trowel it, because it rained when the concrete was being poured, because the trowelling process is not good…
Let’s see the causes of a badly trowelled concrete, its consequences and what we can do to solve it.
Why can concrete be badly trowelled?
The main reasons why concrete may be poorly trowelled range from problems in the application process to unfavourable environmental conditions:
Inadequate preparation
If the base on which the concrete is to be applied is not properly prepared, levelled or compacted, it can lead to an uneven or poor trowelled finish.
Incorrect mixing
A concrete mix with the wrong ratio of water, cement, sand and aggregate can make the trowelling job difficult. Too much water will make the mix too runny and difficult to handle, while not enough will make it too dry and complicate levelling and smoothing.
Improper drying
Concrete needs to be kept moist for an adequate period of time to cure properly. Rapid or uneven drying or curing can lead to a poor quality trowelled finish, with the possibility of cracking or flaking.
Unsuitable tools
The use of unsuitable tools for trowelling (such as worn trowels, non-straight rules, etc.) can prevent a smooth and level surface from being achieved.
Lack of experience
Lack of experience or skill in trowelling can result in an uneven finish. This includes poor technique in the use of the vibratory screed, trowel, or not following the proper timing for the different trowelling stages.
Adverse weather conditions
Wind, rain, high temperature and humidity can affect the quality of trowelling. For example, trowelling on an extremely hot day can cause the concrete to dry out quickly, making it difficult to work the surface properly.
Incorrect admixtures (or in inadequate proportions)
The use of admixtures to modify the properties of the concrete (such as setting retarders or plasticisers) without following the manufacturer’s recommendations can alter the workability of the mix and adversely affect the final trowelling result.
The problems of poorly trowelled concrete
Attention to detail and correct technical execution are crucial to avoid problems in the trowelled concrete finish, thus ensuring a smooth, uniform and durable surface.
Increased porosity and low strength
Inadequate trowelling of concrete can have serious consequences for its durability and functionality. Poor compaction leads to increased porosity, which means that water and other chemicals can penetrate more easily, accelerating the deterioration process. This leads to corrosion of reinforcing steel (if your concrete has it) and increases the risk of damage from freeze-thaw cycles.
In addition, a porous surface is by default weaker: concrete is less able to withstand heavy loads and more susceptible to wear and tear from regular use (so imagine if heavy machinery traffic is intense).
This can result in the need for frequent repairs and, ultimately, a shorter service life of the concrete structure.
These problems not only compromise the structural integrity of the concrete but also significantly shorten its service life, leading to costly repairs and a reduction in the safety of the affected structures.
Concrete spalling
Spalling, caused by excessive trowelling or in excessively wet conditions, results in the separation of the top layers. This phenomenon compromises the uniformity of the surface, generating irregularities and leading to the accumulation of water, which deteriorates both the aesthetics and the functionality of the pavement. This type of damage affects not only the appearance of the surface, but also its durability and ability to handle traffic and loads, increasing the risk of accelerated deterioration.
Cracking and cracking
Inadequate trowelling leads sooner or later to uneven curing of the concrete, resulting in internal stresses, cracks and crevices. These imperfections not only deteriorate the appearance of the concrete and the image of your company, but also weaken its structure.
Adhesion problems with coatings
A poorly trowelled concrete surface faces adhesion problems when attempting to apply coatings or surface treatments (such as paints or sealants). This occurs due to the lack of proper surface preparation, which is crucial to create an effective bond with such coatings. A properly prepared surface is essential to ensure the durability and effectiveness of these subsequently applied treatments.
Poor aesthetic finish
Poor trowelling not only affects the functionality of the concrete, but also impairs its aesthetic appearance, resulting in a surface with inconsistencies in texture and colour. This can be especially problematic in contexts where the visual finish is critical (e.g. showrooms), compromising not only the structural integrity but also the aesthetic value of the project.
What can be done to correct poorly trowelled concrete?
To correct problems caused by poor concrete trowelling, it is crucial to adopt an approach that not only addresses the visible symptoms, but also tackles the underlying causes.
Here are some effective solutions:
Surface repair
The first step is to fill cracks and fissures, using repair mortars specifically designed for filling and sealing. The aim is to restore the integrity of the surface and reduce the penetration of water and chemicals. Concrete coatings or overlays can then be applied to renew worn or aesthetically damaged parts. This improves uniformity and wear resistance.
Improving the trowelling and curing process
It is important to ensure that trowelling is carried out at the optimum time, i.e. when the concrete has lost its surface gloss but is still workable. In order to employ proper techniques and tools that will prevent over-handling, it is essential to call in a specialist company. It is recommended to implement effective curing practices, such as the use of curing membranes, constant watering or protective covers, to ensure uniform hydration and reduce the risk of cracking.
Surface preparation and treatment
Thorough cleaning and good surface preparation (sandblasting, milling or scarifying) should be carried out before applying coatings or sealants to improve adhesion. The use of specific primers improves the adhesion between the concrete and subsequent coatings.
Use of repair materials
It is crucial to use modified repair mortars, which offer better adhesion, strength and durability compared to conventional mortars. Reinforcement fibres can also be incorporated into repair mixes to improve mechanical strength and control crack formation. Preventive maintenance It is recommended to establish a regular maintenance programme to identify and repair small problems before they become major damage. Ideally, organise regular assessments by specialists to determine the structural health of the concrete and anticipate maintenance or repair needs.
By applying these solutions, it is possible not only to correct problems caused by poor trowelling but also to improve the durability, functionality and aesthetics of the concrete, thus ensuring that structures meet their long-term performance requirements. If you have noticed any of these problems with your industrial floor, contact us now.
