Damp, mould, stains and flaky plaster in basements are a homeowner’s worst nightmare. We’ve mentioned numerous times that weather events and groundwater, where not controlled properly, are the main cause of damp. Of course, it doesn’t just affect the walls, but the whole structure, including flooring, on the basement level or even on the ground floor.
The phenomenon that’s so often underestimated is so-called “rising damp”, which occurs when water under the ground enters walls as a result of direct contact and is pushed upwards by capillary action, allowing the moisture to rise around ten centimetres or more. The moisture can even climb metres up the wall by “latching on” to molecules of a different kind, in this case those of the actual walls. The damage caused by the abnormal increase in moisture inside walls is immediately visible on the walls of ground-floor rooms or basements.
What effects the water’s capillary action has
The effect of capillary absorption manifests in the form of:
- static damage to the building, which is weakened and becomes less safe
- worsening occupant comfort as a result of unhealthy, smelly rooms
- cosmetic damage, with the appearance of stains and peeling plaster
- higher heating costs due to the lower surface temperatures of internal walls
- a capillary action that causes water to rise through walls, bringing with it salts from the ground that, once they crystallize as a result of the evaporation process, swell and cause paint and plaster to peel: white stains forming around cracks are known as salt efflorescence.
The effects are less visible when the surface affected is flooring, with symptoms like swelling, salt efflorescence, mould or changes in the colour of grout often only appearing later on.
All these issues derive from the misguided choice of materials, or poorly designed and executed work, often compounded by the fact that the foundations’ waterproofing is damaged or even non-existent. This is not an issue linked to weather events, rather it stems from the presence of groundwater.
How TeMa Building Solutions can help
Both rising damp and efflorescence issues can be prevented with the use of suitable materials. TeMa Building Solutions offers an extensive range of studded membranes and drainage geocomposites to remove water before it comes into contact with the structure and to provide waterproofing with reliable, lasting protection.
Our engineers are here to help you choose the right specific product for your next project.
The health of walls in contact with the soil — like foundations and below-grade walls — is the primary concern of the home’s occupants, especially where underground garages or basements are involved: any sign of damp or mould is evidence of damage that can have serious financial consequences in these areas of the building. And restoring the interior to good health is not always feasible.
The risks lie both in the foundations — namely in the horizontal structures that receive and absorb the loads of the whole building — and in the below-grade walls, namely the vertical structures that have to withstand considerable loads. If we take the worsening weather patterns of recent years and add in pesky capillary rising damp, and groundwater pressure, there’s clearly a need to ensure the products used provide improved performance.
How do we best protect foundations and below-grade walls?
The way to keep underground rooms healthy is to use specific, tried-and-tested products, applied correctly as per the technical literature. TeMa Building Solutions has various solutions on offer.
Bentonite geocomposites can be used to ensure the concrete is properly waterproofed. Comprising natural sodium bentonite, they self-bond to concrete (if used as waterproofing prior to insitu casting) and are suitable for both vertical applications (below-grade walls) and horizontal applications (slab foundations).
Studded membranes are one of the most widely used products given their dual function:
- they mechanically protect waterproofing: they prevent damage to the waterproofing layer during the backfilling and compaction process at the construction phase, and protect from the subsequent micro-movements as the soil settles, and the considerable loads that the walls have to withstand
- they serve as damp-proofing: they stop moisture, which — even in the absence of hydrostatic pressure — can undermine the structure and cause patches of mould to appear on internal walls.
They reduce hydrostatic pressure exerted on vertical walls, conveying water away from the walls to the outer perimeter. They are laminated with one or two nonwovens serving as a filter layer, stopping the system becoming clogged. The TeMa Building Solutions range includes geonets, studded membranes and monofilament structure.
Need help choosing the right product? Contact us! Our experts are here to help you any way they can.
Serving multiple functions, drainage geocomposites are a perfect match for geotechnical applications, while they have a number of distinctive properties making them a popular choice in the building industry, too. TeMa drainage geocomposites are light, easy to handle both by carriers and on site, quick to apply… But let’s take a look at the full picture in detail.
What are drainage geocomposites and what different types are there?
Drainage geocomposites are, by definition, permeable geosynthetics comprising at least two elements (one synthetic element and one or more nonwovens).
TeMa offers three main types of drainage products, which all come with the benefit of its considerable experience:
- Geonets, made up of a synthetic HDPE mesh comprising two criss-crossed strands sandwiched between two PP nonwovens to which the mesh is thermally bonded, like T-Drain.
- Geomembranes like T-Kone and TMD, HDPE studded membranes with different stud heights (8, 10, 20 mm) laminated with a nonwoven.
- Monofilaments, made up of an extruded synthetic monofilament core sandwiched between two nonwovens to which the core is thermally bonded, such as T-Mix Drain.
What are their possible applications?
The drainage geocomposites from TeMa Building Solutions cover numerous applications: pitched roofs and ballasted flat roofs, flat green roofs and trafficable flat roofs, standing seam metal roofs and walls, foundations and underground structures, and damp-prone internal walls.
These are all applications that require special attention to drainage as they are exposed to different weather conditions and, in some cases, to groundwater as well: the risk of ponding increases, encouraging damp and, if the waterproofing layer becomes damaged or has too much pressure on it, water seepage and leaking can become an issue.
What purposes do drainage geocomposites serve?
Their main purpose is draining rainwater and groundwater. This is achieved by the action of separation, made possible by the nonwoven, which acts as a filter: the particles that manage to get through it are so extremely small as to have no effect on the proper functioning of the drainage system.
The studded membrane geocomposites also serve the important purpose of providing mechanical protection for waterproofing, which is valuable in roofs and simply essential in underground structures if they are to cope with backfilling and settling of the backfill without being damaged.
Which drainage geocomposite should you choose?
To choose the right product, you need to look at what performance is required. Designers know this well: it depends on the amount and “quality” of water to be drained, and hence on the morphology of the site, whether there are active aquifers, and so on. Loading is another factor to be taken into consideration, in such applications as green roofs, as well as for trafficable roofs and walkable surfaces.
Some of the most widely used works in the civil engineering field are diaphragms and berlin walls, which counteract strong thrusts of the soil and prevent landslides and structural subsidence.
Diaphragms are supporting walls consisting of pointed vertical elements (piles) or continuous elements (walls) made of steel or reinforced concrete. They are driven into the ground to a considerable depth, whereas Berlin walls are flexible retaining structures constructed with vertical micro-piles.
Both solutions are used where it’s impossible to construct excavation walls of an adequate gradient due to the presence of other nearby structures and to the morphology of the area , which imposes limited work spaces (that would make manoeuvring large machinery impossible).
Berlin walls made of micro-piles are one of the most popular applications on construction sites for implementing waterproof retaining works. The technique allows work to be carried out on almost all types of terrain, especially when it’s necessary to use on-site systems that are smaller than in the past.
Since works are in contact with the ground, the drainage aspect should not be underestimated. If rainwater and groundwater exert pressure on the vertical wall, they may damage the waterproofing. TeMa Building Solutions therefore has the right product for this application: T-Mix Drain WP, the geocomposite that not only drains but also provides the functions of filtration, separation and stay-in-place formwork.
TeMa has acquired considerable experience with geocomposites. For many years, the company has been providing this system to replace the conventional gravel drainage system. The results are long-lasting and it’s the ideal solution: compared to conventional gravel, it’s less bulky, easily transported and quick to install. This reduces the costs of transport and implementation and on-site construction time while, last but not least, resulting in considerable savings in terms of CO2.
Fields of application
As mentioned above, diaphragms and berlin walls are widely used where space is limited. More specifically, they can be used in the construction industry, for example for underground garages in homes or commercial premises, for basements. They can also be used in river works, such as quays and piers for boats, or in earth dams and wells.
Having the experience of TeMa technicians and tested effective products such as T-Mix Drain WP at your disposal is therefore a guarantee for your construction site.
City centres are overcrowded with vehicles and restricted areas, car parks are “stressed” and there are never enough spaces to go round. Alongside the more “standard” trafficable ceiling slab solutions — such as in the case of underground garages — it’s not too much of a stretch, where structurally feasible, to think about designing or making better use of spaces on elevated levels.
Over the holidays, car parks on the roofs of public buildings or buildings for use by the public could also provide refuge for the cars of passers-through. During the offices’ closing time, for example, these parking spaces can become a real asset, an ideal solution for making use of otherwise unused space and increasing the number of car parks for people travelling to tourist hot spots
Continual vehicular traffic and exposure to the elements — from freezing temperatures to sweltering heat — mean the construction materials used must be fit for purpose. Intensive use means it’s imperative all the proper layers are in place (build-up design) to serve the different specific functions. Let’s see what these layers are.
What do we need to be careful about when designing a rooftop car park?
This kind of roof is subjected to high loads, both static and dynamic, from vehicles of all kinds. This makes the mechanical protection of the waterproofing layer and the need for high compressive strength two key focus areas.
Drainage is another aspect to be factored into the design. Rainwater can seep into the underlying layers and damage them, so we need to ensure that water is drained off the roof properly.
We recommend applying studded membranes laminated with nonwovens or drainage geocomposites made from monofilaments or geonets.
Our drainage geocomposite T-Mix Drain Plus is a good candidate for the drainage layer. Alternatively, you can opt for the T-Net Drain 5 and T-Net Drain 7 geonets, which are sandwiched between nonwovens.
The job of mechanical protection, together with drainage, can instead be handled by the drainage geocomposite TMD 1011. The product consists of a filter geotextile laminated to a studded membrane, whose conformation delivers effective drainage even under the strain of high loads (up to 400 kPa).
Nowadays, certain solutions allow you to create perfectly liveable and comfortable basements.
Of course, existing little-used basements can also be renovated, but you need to take some constructive measures to ensure that the building is in good condition and the environment is healthy.
So let’s see what we need to focus on.
Damp and moisture seepage
Basements are in direct contact with the ground, both the floor and the vertical walls.
Rainwater or ground moisture can penetrate concrete, leading to marks and mould that may cause the wall to peel. The aesthetic damage is as serious as the structural damage: mould is anything but healthy!
It therefore becomes necessary to provide a separation barrier between the structure and the ground that performs the function of damp-proofing, i.e. controlling moisture in the absence of hydrostatic pressure (click here to read more).
TeMa Building Solutions suggests T-Bentostop, in the F and F XL versions, a geocomposite, which attaches to concrete and consists of natural sodium bentonite with a waterproofing function, and T-Kone, the HDPE studded membrane available in several versions.
Groundwater or dispersed water may flow in the ground, even near structures, therefore increasing the load on walls. So, it is essential to drain water and prevent it from entering by reducing the hydrostatic pressure on surfaces: T-Kone G Drain, T-Net Drain studded membranes and the drainage geocomposites in the T-Mix Drain range perform this function while keeping walls dry.
Mechanical protection of waterproofing
The vertical walls of basement rooms have to withstand heavy loads exerted by the ground. It is therefore essential to provide systems to protect the waterproof layer in order to guarantee the safety and long life of the building.
The T-Kone, T-Kone Star and TMD (also in the Plus version) range are studded membranes specifically designed for foundations and underground structures: their high load-bearing capacity makes them ideal for such applications.
To keep masonry dry and allow constant and substantial air circulation, studded membranes can be installed with the studs facing inwards. In this way, their raised shape creates aeration channels that allow the wall to literally “breathe”.
Ideas for renovating your basement
It has been estimated that the value of your property increases by about a third if you have a well-planned basement. An extra room is always very useful and its intended use may vary greatly.
You can opt for a studio for working from home, a spacious laundry room for hanging up your washing, a playroom for your children, a relaxation area, a rehearsal room for talented home musicians, or even a free space for hosting friends, a wine cellar for preserving the best bottles with a tasting area, a gym or a personal home cinema.
“A hole in the roof is enough to ruin a home.”
So the (Italian) saying goes. Of course, there may not be any holes in the roof in the strict sense of the word, but, unfortunately, in a broad sense there might be. Roofs are subject to problems such as water seepage, damp and, in the case of trafficable flat roofs or car park roofs, heavy loads.
The roof is the part of a building directly exposed to weather conditions, such as rain, snow and hail, but also to heavy loads. It’s the least visible part of the house and the most difficult to inspect. When building a roof, it’s therefore essential to consider factors that might affect its integrity and safety, as well as harm the health of occupants.
Water seepage leads to damp and peeling walls. Dampness means mould and unhealthy attic environments.
So, let’s take a look at the main problems and see what solutions can be found.
Ponding on a roof will wet and ruin the materials used. It’s therefore necessary to install a drainage system for rainwater or, in the case of trafficable flat roofs, for accidental leaks of oil or fuel from vehicles. This applies to green roofs, trafficable flat roofs and ballasted flat roofs.
Solutions need to be found that don’t increase the “load” on the roof.
TeMa Building Solutions recommends installing its drainage geocomposite , T-Mix Drain Plus and TMD 1011, ideal for trafficable flat roofs and flat green roofs; its T-Kone G Drain studded membrane, suitable for ballasted flat roofs and flat green roofs; or T-Net Drain geonet for trafficable flat roofs.
It’s also necessary to focus on vapour control. Due to temperature differences between the air and the roof material, there’s a risk of condensation forming. To prevent this, highly waterproof vapour diffusion membranes need to be laid.
The membranes in the T-Vapo range act as a barrier, retarder and vapour diffuser for pitched roofs.
Mechanical protection of waterproofing
The first step is to ensure that the waterproofing layer is intact and remains that way. Any cracks, cuts or inaccurate application in corners can cause irreparable damage to the underlying surface, requiring major intervention and considerable costs. By the time damp patches appear, the damage is often already severe.
Moreover, in the case of roofs used as parking areas or flat green roofs, the heavy weight that the materials need to withstand must be considered.
TeMa Building Solutions proposes its T-Kone G Drain studded membrane and the Tematex range of geotextiles for flat green roofs.
Supporting walls or retaining walls are vertical structures intended to support and retain accumulations of natural or artificial materials and ensure their stability.
In the part in contact with the ground, the supporting structures are naturally covered with a waterproofing membrane, which must be protected from damage during construction operations and during subsequent settlement of the ground. The mechanical protection of the waterproofing is provided by TeMa Building Solutions T-Kone studded membranes, which also act as damp proofing, slowing down the absorption of moisture.
Moreover, when placed with the studs facing inwards, these membranes create a micro-ventilation space that is beneficial in keeping the structure dry.
In some cases, a rainwater collection system is planned around the perimeter of the building. It is necessary to use drainage geocomposites bonded with a geotextile such as T-Mix Drain, which conveys water to the drainage system envisaged in the project.
Supporting walls are used in a wide variety of areas in the building industry, from residential to infrastructural and commercial contexts.
Let’s take a look at the application in specific fields.
It is essential to protect the underground rooms of homes, whether they are used as garages, cellars or basement rooms, in order to prevent the moisture seepage, which would damage the structure and make the indoor environment unhealthy.
TeMa Building Solutions products meet this need and are efficient in this respect.
TeMa Building Solutions products are also ideal for heavy loads such as underground car parks or warehouses in commercial buildings.
In such environments, TMD, the studded membrane bonded with LDPE backing foil for the mechanical protection of waterproofing membranes and the T-Mix Draindrainage geocomposite for the drainage function can also be used. In addition, the T-Comp fibreglass mat performs the subdivision function.
In major infrastructural works, membranes and geocomposites must be able to withstand and resist heavy loads from the ground and hydrostatic thrust. The effectiveness of TeMa Building products is also proven for this type of construction work.
To learn more about the mentioned products, click here.
Just imagine the face of those present when Elisha Otis, a smart American entrepreneur, presented the first elevator in 1853. It was enlightening! During an exhibition at Crystal Palace in New York, visitors were shown how the enclosure works, which was fitted with an automatic safety device for blocking it in the event of an emergency.
Today, however, we are used to using elevators and we often complain if they are out of order and we have to go back to the old-fashioned habit of using the stairs!
But what does building an elevator involve?
Elevator pits are structures located at a lower level than the internal standing area and must be able to withstand both static and dynamic loads. In short, they need to not only support the weight of your Saturday shopping but also take it up to the fifth floor!
Many problems may be encountered when an elevator is being installed. First of all, there is the danger of infiltration and all the consequences it may bring. Then we mustn’t underestimate the fact that, in the case of a hydraulic elevator, oil may leak from the system, which is why electric elevators are always recommended. TeMa has developed the T-Kone family: HDPE honeycomb membranes that provide mechanical protection, damp proofing and drainage. As far as drainage is concerned, the research and development centre that TeMa relies on has developed drainage geocomposites that filter, protect and drain the system.
Waterproofing? Yes, but how
It is not enough to install membranes that perform a drainage function, it is also necessary to make spaces waterproof. But how? By using bentonite geocomposites that self-bond to concrete, such as T-Bentostop F and T-Bentostop F XL. They are made of a non-woven fabric and a polypropylene fabric with a layer of natural sodium bentonite in between.
These are the essential aspects that should never be underestimated for excellent, high-performance implementation. We must always remember that a thorough preventive analysis of the dangers, along with accurate and responsible installation, are the best techniques for avoiding problems and inconveniences caused by infiltration in the future.
Find out more about damp proofing, drainage, mechanical protection and waterproofing systems of TeMa Building.