Advantages of plastering
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Want to be absolutely sure about the exact moisture problem you are struggling with? Our moisture experts will visit you free of charge and without obligation.Contact our specialists today for more info and advice.
How can I tell from my plasterwork that I am suffering from a moisture problem?
There are several ways you can recognise a moisture problem. In fact, there are a number of situations:
Although the symptoms vary, you will quickly notice that there is a problem with that wall.
What should I do if my plaster is coming loose?
First and foremost, what you should not do is simply repaint, re-paint or re-plaster the wall without addressing the problem at the root cause. By re-plastering the wall, the problem may be out of sight, but not out of mind. In other words, it does not solve the problem. It is important to have a expert address to know exactly what the problem is and what needs to be done to solve that problem.
What are the causes of loose plaster?
When the plaster of your wall starts to come loose, it often indicates a moisture problem. Several moisture problems can be responsible for this, and the most common are:
These problems are all solved in completely different ways. For example, in the case of penetrating damp, the façade is treated to make it water-repellent. This is done by means of facade impregnation or hydrofuge. In contrast, in the case of rising damp injected the walls with a damp-proof gel to block the path of moisture. Condensation, in turn, needs a mechanical or non-mechanical ventilation system. These problems must be solved before we start plastering. Otherwise, the problem will quickly resurface, forcing you to start plastering all over again, with all the attendant disadvantages.
Fixing loose plaster once and for all with AquaConsult
Typically, AquaConsult's moisture experts proceed as follows:
Our technical advisers have many years of experience in diagnosing damp problems and know best what exactly is needed to combat damp.
What are the benefits of plastering as a moisture solution?
Plastering as a moisture solution has many advantages:
With this plaster, AquaConsult provides a paint-ready finish so you can repaint your wall without worry. Are you suffering from loose plaster? Contact AquaConsult now and a moisture expert will visit you as soon as possible to make the right diagnosis. We come everywhere in Flanders with you. Together, we will find the perfect solution.
Does plastering cause condensation?
Plaster in itself does not cause condensation, but it can contribute to its visibility. Fresh plaster brings gallons of moisture into the house during the drying process. If this moisture cannot escape due to a lack of ventilation, then it precipitates on the cold surfaces. Then condensation is caused resulting in condensation moisture. In older homes, which we see a lot in regions such as East Flanders or Flemish Brabant, a new and dense plaster layer can reduce the natural infiltration of air, causing condensation problems to surface more quickly.
Moreover, plaster contaminated with hygroscopic salts can start to attract moisture from the air. This gives the appearance of condensation, when in fact the wall is actually ‘sweating’ due to the salts present in the substrate. A correct free expert diagnosis by AquaConsult is essential to determine whether the problem lies with the finishing or structural damp proofing.
Can you fix moisture problems without removing the stucco?
In most cases, it is technically impossible to identify the source of the moisture, such as rising damp, to be tackled without immediately removing all the plaster. Thus, walls can be injected from the outside or through targeted drill holes. Although the cause is then stopped, the moisture present and the hygroscopic salts dissolved in it remain in the old plaster. These salts attract moisture from the ambient air even after treatment, so moisture spots or salt efflorescence may still remain visible.
For a high-quality and lasting result in your home, we therefore usually recommend removing the affected plaster to at least 50 centimetres above the moisture line. This prevents you from having to deal with flaking paint or loosening plaster again after moisture control. Do you still want to keep the plaster? Then an expert should use an accurate salt analysis to determine whether the concentration of salts is low enough for the wall to simply dry out without further felling work.
How to repair plaster after moisture?
Repairing plaster can only begin after the cause of the moisture, such as rising damp or a leak, has been permanently resolved and the wall has dried out sufficiently. First remove all loose and damaged plaster down to bare stone and that sufficiently above the visible moisture limit. This is necessary because salts from the moisture remain in the wall and can immediately affect new plaster again.
For lasting results, we recommend using a salt-resistant membrane or a specific barrier plaster before applying the new finishing coat of plaster. This prevents residual moisture or residual salts from migrating from the deeper layers of the masonry to the surface. In practice, we see that in renovations in Belgium, this step is often skipped, leading to recurring stains and flaking paint.
What is the normal moisture content of plaster?
For fully cured and dry plaster, the normal moisture content is between 0.5% and 1%. In this condition, it is safe to repaint or wallpaper the wall. During the drying process, this percentage will slowly decrease. At a moisture content above 2%, the risk of paint damage or mould behind the wallpaper still too big.
Because the outside of a wall often appears drier than the core, our experts at AquaConsult use professional gauges or electrical resistance meters to determine the exact moisture content deep inside the wall. Especially in our humid climate, this is the only way to say with certainty whether your plasterwork is ready for the final finishing stage.
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Frequently asked questions about plastering
To combat moisture effectively, the choice of product depends on the type of moisture problem. At penetrating moisture through the outer wall is a hydrofuge or facade impregnation the best solution. For interior walls struggling with residual moisture after treatment, a salt-resistant membrane or a special barrier plaster can be applied before the final plaster finish. It is important to note, however, that patching agents such as damp-proof paint or coatings are often only symptomatic remedies. They trap the moisture in the wall, making the structural damage invisibly worse. For a permanent solution, it is essential to tackle the source first with, for example a wall injection before applying protective layers.
Moisture-resistant plasters, often based on cement or specific resins, are designed to withstand high humidity better than standard gypsum plasters. In areas such as basements or bathrooms, a cement-based cast is often chosen that is less porous and does not soften when in contact with vapour. Be careful, though, because moisture-resistant does not mean the same as waterproof. Even the best plasters can succumb to the constant pressure of rising groundwater or an active leakage. Moisture-resistant plastering is therefore mainly used at AquaConsult as part of a total solution, for example as a finish after a basement drainage To restore the walls aesthetically and functionally.
The most accessible way to measure humidity is with an electric moisture meter (protimeter). This measures the electrical resistance between two pins that you push into the plaster. For reliable results, the value for paintwork should ideally be below 1%. But with this method, you often only measure surface moisture and it can be affected by salts in the wall. For a science-based measurement, experts use a calcium carbide test. This involves taking a drill sample from the wall and mixing it with calcium carbide in a pressure vessel. The resulting pressure then indicates the exact moisture content in the core of the wall. AquaConsult carries out such professional measurements during a free expertise to determine exactly whether your walls are ready for finishing with plastering.
Plaster loosens because moisture breaks the bond between the plaster layer and the underlying stone. When water soaks into the wall, it dissolves the hygroscopic salts present. Once the moisture evaporates on the surface, these salts crystallise. This process of crystallisation creates a huge expansion force that literally pushes the plaster off the wall, resulting in blistering, flaking or powdery plaster. In addition, plaster is also naturally very absorbent. With prolonged exposure to moisture, it loses its structural integrity and becomes soft. If you notice that the plaster sounds hollow when you tap against it, the adhesion has been completely lost and it is necessary to remove the affected areas, treat the wall against salts and re-set it after a thorough damp proofing.
