Moisture and insulation compounds: The relationship in between.
Having discussed the sustainability of insulation materials on this page, we will now explore the inherent connections between the nature of the raw materials used to produce these materials and their performance when installed, highlighting that not all insulating materials are created equal.
In Malta, traditional methods of managing heat and humidity in buildings were closely tied to the intrinsic breathability of local construction materials: Thick, double walls, very high ceilings, small windows with wooden shutters and a very peculiar 'sandwich' roof structure composed of limestone slabs (xorok) resting on limestone arches, a filling with limestone chips mixed with stone dust and lime and an outer surface layer (deffun) of ground ceramic mixed with lime and beaten down to produce a rainproof layer. These roofs utilise evaporative cooling achieved through the intrinsic properties of porous materials to lower the surface temperature of the roof.
In consideration of our particular climate and especially when we work on traditionally built structures, a crucial aspect to keep in mind is how modern insulating materials perform when exposed to moisture. Here, the raw materials used for production play a key role. Typically, products made from petroleum derivatives lack an inherent capacity to manage moisture. They may be engineered at the particle level to to be completely impermeable or to mimic breathability, however, this pseudo-adaptation often leads to a considerable decrease in the product's insulating properties when exposed to moisture.
In contrast, materials of natural origin demonstrate superior adaptability in wet conditions.
Keeping natural is the key:
We'll delve into the top natural-based materials chosen by Attard Bros Construction Materials, aimed at enhancing the energy efficiency of our buildings while prioritizing well-being and sustainability.
Cellular Glass
Materials like cellular glass are inherently completely impermeable, making products like Glapor an ideal choice for insulating against ground surfaces providing both an insulation layer and a moisture barrier in a single solution. Foam glass panels offer lifelong insulating properties being at the same time also a particularly sustainable insulation variant for modern building envelopes. As a plastic-free and environmentally friendly insulation material, Glapor provides optimal properties for climate-neutral construction and systems that can be dismantled.
Calcium Silicate Boards
Materials like calcium silicate insulation panels react to moisture similarly to traditional masonry; they absorb excess environmental moisture allowing its passage through the insulation material without any damage or having their properties altered.
This is the case with products such as TERMOKÜP, B/Sana, B/Isola, B/Termo produced by the Italian company Bacchi and which we at Attard Bros Construction Materials import here for the Maltese market.
Mineral Wool
Rock wool and glass wool mattresses are a peculiar case. They are made from materials that are completely hydrophobic. This means they do not absorb moisture; instead, moisture passes through them without altering their technical properties.
Due to poor design, however, moisture may nestle inside the woolly structure of the product, creating pockets of imprisoned humidity that can give rise to problems such as the development of mould, micro-organisms, bacteria, for example.
In such instances, the issue does not stem from the material itself but from the inability of moisture to migrate, preventing the insulation layer from drying naturally. For this reason, this insulation type is often shielded with impermeable or monotranspiring layers to prevent dampness, especially when quick drying cannot be assured.
Insulating from the inside.
Renovation encompasses a range of interventions in a building, including modernization, retrofit, restoration, rehabilitation, maintenance, repairs, and routine upgrades. Energy renovation often plays a hidden yet crucial role in these processes, contributing varying levels of energy savings. For instance, while upgrading a gas boiler in a house has its benefits, it pales in comparison to insulating the façade, roof, and external walls, which can greatly diminish energy loss through the building's envelope and substantially enhance the home's energy efficiency.
Unfortunately, an energy upgrade is often conflicting with the possibility of insulating the building from the outside. This is the case, for example, with historic buildings or buildings in general whose original external appearance is to be respected. Likewise, work is usually conducted internally, even in a large building complex like an apartment block, where a single owner may independently decide to undertake insulation work in their flat.
Often, the solution is to apply insulating panels internally. However, if non-breathable materials are used, it can lead to the wall becoming dampproofed. Similarly, building a counter-wall, such as one made of plasterboard, with internal insulation and a vapor barrier, will also prevent moisture from entering the insulation from the rooms. A superficial design may convince people that these methods are adequate to prevent issues, but in practice, the outcome may be quite different.
Fifty years ago, building engineers thought sealing houses with membranes, cement, or enamel would mitigate moisture issues. However, this is akin to wearing a diving suit all day; it blocks external water but traps internal moisture, hindering dynamic exchange. In such cases, air vents and ventilation are insufficient to restore a healthy living environment.
In general, the placement of a vapor barrier is determined by the direction of heat flow and consequently, humidity, which naturally migrates from warmer, more humid areas towards cooler spaces or outside across the partitions. With a particular climate such as ours here in Malta, in the presence of high relative humidity it will be easy to incur in inversions of hygrometric flows, a situation which will make the presence of the non-breathable insulation or vapour barrier an obstacle to the correct functioning of the building envelope, compromising the breathability of the wall.
This type of assessment can be carried out by performing a variable regime calculation according to EN 15026.
Natural, sustainable, healthy.
The evolution of building materials has lived up to its hype. Following a period of intense dependence on innovation, chemical products, and highly industrialized production, we are now revisiting traditional building methods. This revival has led to an appreciation for the inherent qualities of various natural raw materials. Leveraged by technological advancements and a comprehensive approach to construction, these materials enable us to build the new in a more sustainable way, as well as to enhance the standards of existing buildings more seamlessly.
Products based on natural raw materials are not only the most sustainable in terms of production processes but also promote healthy and comfortable environments through their inherent ability to interact with their surroundings. These materials are devoid of harmful emissions, both at the time of installation and over the long term, offering an additional remarkable advantage from their utilization.
The materials provided by Attard Bros Construction Materials to the Maltese market are certified for environmental sustainability and are derived from sustainable raw materials. Consequently, they support the attainment of energy and environmental impact goals essential for obtaining key sustainability certifications for buildings.
