The Difference Between Tanking & Waterproofing
Written by Warren Muschialli
The difference between waterproofing and tanking
We are frequently asked about the difference between tanking and waterproofing. This is a common question for people who are looking to convert a basement or cellar into a dry space. Basement waterproofing typically refers to all types of waterproofing system (barrier, integral and drained waterproofing). Basement tanking, or cellar tanking, describes the application of one type of coating or membrane (barrier protection). We provide products for all types of waterproofing, and often recommend that systems are combined for optimum protection against water.
What is Basement Waterproofing?
Basement Waterproofing is the general term for all methods of waterproofing used to keep basements or cellars dry. This includes the installation of a ‘Type C’ Cavity Drain System. This system manages water seeping into the property and moves it safely away to a pump or safe drainage.
Tanking a period basement.
What is Basement Tanking?
Basement Tanking is the application of a membrane or coating to the inside or the outside of the structure. This stops water entering the habitable space of the property thus making the basement watertight. Within the waterproofing industry this is defined as ‘Type A’ waterproofing.
Does tanking stop rising damp?
Tanking and/or waterproofing are required when the structure sits below the ground, meaning the ground outside is a route for water to be delivered against the structure. This water can penetrate through the fabric of the walls and floor and requires a barrier system (tanking) or water management system (waterproofing) to deal with this occurrence.
Rising damp is generally associated with walls situated above the ground where moisture from the ground rises through the capillaries in the wall fabric, this is known as capillary action. The most common treatments for treating capillary held moisture and rising damp are chemical damp proof courses combined with renders including salt retardant or waterproof additives and cavity membranes which provide an impervious barrier to moisture and moisture vapour.
It’s important to have your property checked by a professional before undertaking any damp proofing work. They will be able to advise you on the extent of your damp problems and offer solutions for the best way to prevent any further water damage and to keep the interior of your property permanently dry.
What are the options for tanking and waterproofing an existing property?
- Option 1 – Cavity Drain System – comprising waterproof membranes, drainage, pumping, and control systems. These systems manage water entering the property and safely remove it.
- Option 2 – Tanking Membrane, Coating, or Slurry to hold back the groundwater from entering the building.
- Option 3 – A combination of the two for maximum protection. This should be considered if the structure is very porous and so at the risk of allowing too much water to enter for the Cavity Drain System to deal with. In all cases, the flow of water should be stemmed as much as possible.
A Cavity Drain System comprises waterproof membranes, drainage and/or pumps working together to safely remove water entering the building.
A Tanking Membrane or Coating provides a physical barrier to prevent water entering the building.
The safest approach
We always recommend that a Cavity Drain System is included as part of the waterproofing approach for existing structures. This solution is much less risky than relying on a tanking membrane or coating.
If the tanking is defective due to poor installation, preparation, or impact damage, water will enter the structure and compromise the internal habitable space. Because a Cavity Drain System does not resist the water ingress, it is much less susceptible to these issues and will remain effective even when the membrane is slightly damaged.
The waterproofing design should consider the possibility of the full height of water around the structure. This is true even where investigations show that the groundwater level is lower than this. Changes to watercourses, perched water tables and even burst water pipes can quickly result in full ground saturation and a full head of water pressure.
What the British Standard for Waterproofing recommends
British Standard for Waterproofing, BS 8102:2022 is used by architects and designers to ensure that basement waterproofing is carried out in the safest possible way. The British Standard recommends ‘Type C’, or Cavity Drain Membrane Waterproofing is maintainable.
Before and after: The existing timber staircase core was also protected by the CDM System.
The Newton CDM System utilises drainage channels that are placed at the weaknesses within the structure to depressurise and collect water entering the property. This drainage system includes accessible Inspection Ports which allow for the waterproofing system to be accessible and maintainable. ‘Type C’ waterproofing without these drainage channels are not maintainable and so fall foul of the recommendations within BS 8102:2022. Thus, these installations are not allowed by most major UK building insurance companies.
Newton Specialist Basement Contractors will always use a maintainable Cavity Drain Waterproofing System. They will provide the homeowner with a meaningful, underwritten guarantee for the waterproofing.
Please contact us if you require any further information about tanking and waterproofing or advice as to the best approach for your project. We work in close partnership with our Newton Specialist Basement Contractors to ensure the safest installation of our products and associated guarantees. Please contact us using the form below for technical advice and a list of Contractors in your area.
Tanking a Cellar – Basement Tanking Guide
How to Tank a Cellar
Cellars are often damp and unusable beyond storing the odd bottle of wine and old tin of paint. If you want to make full use of your cellar or basement, then you will need to keep it dry. Tanking systems provide an impermeable waterproofing coating to the walls and floor, helping keep cellars dry.
When it comes to waterproofing a basement with damp walls you have two main options:
1) Install a cavity drainage system
2) Cellar tanking
There is some confusion about exactly what constitutes cellar tanking. The term has come to refer to above ground damp proofing as well as cavity wall membranes as part of a basement drainage system. In this article, we are going to focus on cellar tanking as per the following definition.
What is Cellar Tanking?
Cellar tanking or basement tanking refers to the application of a liquid waterproof coating (tanking slurry) to the walls and floor of a cellar. It is used to treat damp walls by preventing water ingress, effectively making the walls permanently watertight.
Damp walls are common in cellars because the walls are below ground. Water from the retaining earth can make its way through the walls and into the cellar. When this moisture passes through the wall, it can also carry salts and minerals with it. Damp walls are cold which creates issues with condensation and in turn mould. Tanking slurry is designed to deal with these issues. It is applied directly to damp walls. When the tanking slurry cures, it forms an impermeable waterproof barrier, preventing water ingress and damp.
It’s important to point out that unlike a cavity drain system, tanking slurry blocks water from entering your cellar rather than allowing it in and controlling it to an evacuation point.
The most effective way of tanking your basement or cellar is with tanking slurry. You may sometimes see this referred to as cementitious tanking. Both names refer to the same product – a specially formulated mixture designed to be applied to cellar walls to stop water ingress. It either comes pre-mixed or as a powder to mixed on site with clean water.
Some people may recommend tanking a cellar with a bitumen coating, but this method is not suitable for tanking an entire cellar or basement. Bitumen coatings are more suitable for smaller above ground areas and external waterproofing.
How does tanking slurry work?
Tanking slurries are a special blend of Portland cements, aggregates and chemical modifiers that work together to block the passage of water. Our PermaSEAL tanking slurry contains an additional acrylic polymer that improves strength, bonding and abrasion resistance.
Tanking Cellar Walls
When it comes to tanking wet or damp walls, you need to prepare thoroughly before applying the tanking slurry. There are several steps you should take to minimise the risk of the tanking failing.
How to Tank Your Cellar with Tanking Slurry
You need to prepare the masonry surfaces thoroughly. In older homes, this can take a long time but preparation is key to a watertight system and well worth the effort.
The first job is to ensure that you can get to the full surface of all the walls (removing all shelves and other items) and that the floor is also clear.
You then need to hack off any plaster and render from the cellar walls along with any previous coatings (bitumen, paints etc) right back to the original masonry. Rake out any old mortar joints and any other loose material before finally making sure the walls are dust free. You will then need to carry out repairs on any existing cracks or holes with PermaSEAL Fillet Seal.
If there are (or have previously been) issues with high levels of salts, it is recommended that you apply a Salt Inhibitor to the cellar walls to prevent any salts from compromising your tanking.
Note: For tanking to work, the brickwork needs to be stable so that it can cope with the build up of water pressure. If this is in doubt, then you will need to take action to ensure the walls can resist water pressure.
Check for Seepage
Once you have removed all materials from the walls, you need to check if there is active water seeping from the wall. If there is evidence of water seepage, you will need to tap off this water pressure where necessary.
Wall floor junction or fillet joint
When tanking a cellar, we always suggest that the walls and floor are coated to create a waterproof box. The point where the wall and floor join can be a potential weak point in any system, we therefore recommend creating a reinforced joint.
How to create a wall floor junction or fillet joint
At the wall floor joint, chase out the floor to a minimum of 20mm x 20mm cutting into the wall if possible. Flush out the chase and remove any debris. Whilst this is still damp, apply one coat of tanking slurry 100mm up the wall and 100mm across the floor. Whilst the slurry is still tacky, apply PermaSEAL Fillet Seal over the tanking slurry and into the chase creating a cove from the wall to the floor.
Mixing the Tanking Slurry
Make sure you keep your skin covered and wear gloves, a facemask and goggles before mixing the tanking product. Tanking slurry is alkaline in its powder form therefore you need to avoid contact with skin or eyes and avoid inhalation of the powder.
Most tanking slurries come as a powder and require mixing on site. When mixing on site, you will need to follow the manufacturer’s instructions. Only mix enough tanking that can be used within 30 -45 minutes as the product will become unworkable and will have to be disposed of.
PermaSEAL Tanking is supplied in 20kg buckets. You should start by adding the required quantity of clean water to a suitable mixing vessel. Slowly add the powder to the water whilst continuously mixing. We recommend mechanical mixing at a slow speed with a high torque drill and a plaster mixer. Mixing should be continued for three minutes after all the powder has been added to the mixing water to obtain a batter-like consistency. Allow the material to stand for one minute before remixing and then applying.
Applying the Cellar Tanking
Cellar tanking products are designed for application onto damp substrates. If your cellar walls are relatively dry you should wet out the substrate fully with clean water, making sure it is damp but with no standing or surface water before applying the tanking.
Tanking slurry requires at least two coats. The first coat should be applied directly to the masonry, brick or concrete surface by brush in a horizontal direction. You should go down and across the wall floor joint and apply the slurry a 100mm onto the floor.
The walls should be ready for a second coat in 2 – 24 hours. Before applying the next coat, you want the slurry to be touch dry and able to support a second coat without pulling off. The second coat should be applied over the top, using vertical strokes this time. The wall floor joint should also receive a second coat.
You should always apply the second coat within 24 hours, even if the substrate still looks damp. As long as the surface can support the next coat you should get onto it.
If you are going to leave the tanking exposed for a period of time before rendering, you should apply a third splatter coat after approximately 1 hour in order to ensure an adequate key later.
Note: PermaSEAL cellar tanking comes in two colours – grey and white – so that you can use a different colour for each coat so that you can clearly see where you are painting. This ensures that when you apply a second coat you cover all areas.
Tanking a Cellar Floor
It is important to tank the floors of the cellar as well as the walls. We strongly recommend that you tank the cellar floor once you have fully tanked all of the walls.
The same method is followed when tanking a floor. You should still apply two coats, horizontally and then vertically lapping over the fillet joint.
When it comes to a finish, tanking coatings should always be protected so never left exposed. You should apply a floor screed (this can be self-leveling). You can then tile or install other floor finishes on top of the screed if you wish.
You should leave the second coat to cure thoroughly – this takes between 24 and 48 hours.The tanking on the walls will cure at different rates. Wetter parts of the walls will take longer to fully cure.
You may notice moisture as the slurry cures. This is called ‘sweating’ and is nothing to worry about. It is a natural part of the curing process that normally occurs in the early drying stages and is caused by water vapour condensing onto cold surfaces. The level of sweating will vary according to how much ventilation is available and any type of heating used.
Finishing and Decorating
After applying your cellar tanking to both the walls and floor, you can then look at finishes and decorating. You will need to add a breathable render before being able to decorate. After 24 hours, you can render over the tanking surface. Even if the tanking looks damp or darker in certain areas a render can still be put over the surface as the whole area will dry together.
As with most tanking slurries, PermaSEAL Tanking needs to be covered by at least a 10mm coat of three parts sharp washed sand to one part cement or PermaSEAL Renovating Plaster. After this render coat has been applied and allowed to dry, dot and dab plasterboard or a multi finish can be used. We do not recommend using paint directly on the tanking.
Because the substrate behind the tanking surface will never dry out, it is very important that any re-decoration doesn’t act as a vapour barrier. Only vapour permeable materials such as trade emulsions and ordinary wallpapers should be used. Gloss paints, vinyl emulsions, together with vinyl and washable wallpapers should be avoided as these will ‘trap’ moisture behind the decorated surface causing future problems. Any re-decoration within 12 months after the completion of the works should only be regarded as temporary.
Cellar Tanking Cost
In order to work out your cellar tanking costs, you need to look at all of the products required, the quantities and also factor in labour costs. As a guide to costs, we’ll take you through calculating the tanking costs using PermaSEAL grey tanking slurry. You would need to also add on the cost of fillet seal for wall/floor joints.
How much does Cellar Tanking cost?
The cost of tanking a cellar depends on the size of your cellar, the type of substrate and the extent of the damp.
Most cellar tanking costs will be calculated on a metre squared basis and be an estimated range. For example, PermaSEAL tanking slurry comes in 20kg buckets – this will cover between 6.5m² to 10m² a unit depending on the substrate.
The grey slurry is currently available at £29.50 excluding VAT. If we take the lowest coverage estimate of 6.5m² per bucket, then the cost of cellar tanking works out at roughly £9 per m² for two coats. Now, if you have four equal walls at 2 metres high and 5 metres long then this would come in at 13 buckets for £383.50 ex VAT for the wall with the floor being a further 8 buckets at £236.00 ex VAT. This would mean tanking your cellar would cost a total of £619.50.
Permagard – Stockist of Cellar Tanking Products
At Permagard we stock a wide range of cellar tanking products including grey and white tanking slurries at low trade prices.
If you have any questions about tanking a cellar or installing a basement waterproofing system then we are more than happy to provide free technical advice. Call us on 0117 982 3282.
Converting a Basement
Creating a Basement Home Cinema
Professional Tanking Brush
PermaSEAL Tanking Slurry Grey
PermaSEAL Tanking Slurry White
Basement waterproofing from inside and outside from ground water
When basement waterproofing is required
Since a basement is called a room below ground level, it is more or less exposed to moisture. It can be surface storm or groundwater, the pools of which are located on water-resistant clay layers and a certain distance underground.
Therefore, waterproofing the basement of a house is an obligatory stage of construction work and is always present during their implementation. Its use contributes to:
- Preservation and, accordingly, an increase in the service life of concrete walls, basement floors, their internal fittings.
- Reducing dampness in rooms, which causes corrosion of metals, destruction of interior items, finishing coatings, contributing to the spread of fungus and mold.
- Improving the microclimate in basements by lowering the level of humidity in them and preventing the air temperature from dropping in cold weather.
Types of basement waterproofing against groundwater
Differences in the types of waterproofing are determined by the technology of their application. On this basis, the following types of waterproofing devices in basements are distinguished.
This is a method of applying creamy waterproofing components with brushes, rollers or spatulas.
According to this method, the basement is waterproofed from the outside from groundwater using bitumen-containing mastics protected from soil damage.
From the inside, waterproofing deep-penetrating compounds on cements and mastics on a polyurethane, acrylic base are applied with a coating.
Generally, mastic waterproofing is applied to concrete surfaces with brushes in at least two mutually crossed layers.
Bitumen-based, polymer-bitumen based welded rolls are commonly used for basement waterproofing from the outside. Inside the technical premises, self-adhesive bituminous rolls are used on the floors.
Also horizontal waterproofing is done with loosely overlapped rolls before pouring the foundation slabs.
Another common area of application for bituminous rolls is the device of cut-off waterproofing between the horizontal surface of a strip foundation (grillage) and walls made of any materials based on it.
Using the spraying technology, two-component liquid rubber and polyurethane mastics are applied to the outer and inner walls of basements.
This is not such a popular option for basement waterproofing due to the low technical performance of these materials, if they are constantly in a moist state or under the mechanical influence of soil.
Special types of polyvinyl chloride and polyolefin membranes are used to waterproof basements from the outside. They are produced in the form of canvases, the joints of which are soldered using a building hair dryer. Membrane waterproofing is fastened to vertical walls from above using clamping strips or dowels with self-tapping screws.
Planter profiled membranes are widely used for waterproofing and protecting vertical walls underground. From above, the canvas is attached to planks or dowels, connecting on the sides by snapping several rows of profile cup-shaped protrusions.
Planter profile membranes are also often used in insulated slab foundations. They are placed on top of the extruded polystyrene foam insulation, then the reinforcing cage and formwork around the perimeter are mounted. After the reinforcement is poured with concrete, thus forming a waterproofed foundation slab.
The principle of operation of this type of waterproofing is their deep penetration into the porous structure of concrete. After that, the composition crystallizes and reliably closes all the smallest concrete pores.
Deep penetration waterproofing includes cement-based coatings.
Specially for concrete, clogging impregnations are produced that fill its pores after crystallization. They are used both in finished structures and when pouring, adding to the concrete mixture.
Liquid glass, which is usually used indoors for waterproofing walls or floors, can be classified as a separate category of impregnations.
Another class of waterproofing impregnations are hydrophobic liquids that create a waterproof film on the concrete surface.
The main purpose of plaster is to level walls for high-quality installation of finishing coatings. Therefore, it is more often used in situations where waterproofing of a brick basement from the inside from groundwater is required, or for walls made of concrete blocks. To increase moisture protection, non-shrink cements, sealing and water-repellent materials, and elastic polymers are added to plaster compositions.
Plaster mortars are applied by conventional manual or machine methods in a layer not exceeding 25 mm. If a greater thickness or several plaster layers of waterproofing are required, a printed metal mesh is used.
There is also a technology for applying plaster waterproofing by spraying using special cement guns.
Injection waterproofing with injection under pressure into the structure of concrete, brickwork with liquid compositions is a modern high-tech method for solving complex problems. There are also non-pressure methods for supplying injection reagents to problem areas through glued packers (guide tubes), by gravity into slots or drilled holes.
First of all, injection basement waterproofing from the inside from groundwater is used to seal cracks in concrete, brick walls, floors, through which water enters underground rooms.
With the help of injection, cut-off waterproofing is restored, the destruction of which leads to wetting and waterlogging of the walls.
Another area of application for injection waterproofing is to reinforce and create a layer of waterproof soil outside basement walls.
One of the important purposes of waterproofing is the sealing of seams, utility lines in concrete, brick and other building structures.
In this case, elastic cementitious compounds or synthetic tapes are used for joint waterproofing. The latter can have a self-adhesive base, or an elastic cement waterproofing is additionally used to fix them.
Entrances around pipes or electric cables are waterproofed with mixtures based on cements, a number of auxiliary materials (polyurethane sealants, foam rubber seals, cords that increase in volume when wet).
Materials for basement (cellar) waterproofing
The abundance of materials used for external and internal waterproofing of basements, as well as application technologies, greatly complicates the task of their correct selection for high-quality work. Therefore, it is more practical to entrust these operations to specialized firms with the necessary experience.
Modern roll waterproofing is made on the basis of bitumen, bitumen polymers and polymers.
Bitumens can be both of artificial origin from petroleum products, and oxidized (roofing) bitumen with a higher softening point.
To improve the physical characteristics of bitumen rolls, polymers are added to them: styrene-butadiene-styrene (SBS) or special polypropylene soluble in bitumen (APP).
Also, rolls with a standard width of 1 m are produced with different bases made of cardboard (Roofing felt), fiberglass (Linocre), fiberglass (Uniflex) and polyester fabric (Technoelast). Their coating for protection against physical, thermal influences, for certain areas of application, is made of coarse and fine-grained powders, a protective polymer film, self-adhesive.
Before purchasing roll waterproofing, it is useful for a consumer to know that, depending on the cost, it is conditionally divided into 5 classes from the most expensive (Premium) to budget (Economy).
Mastics presented on the construction market are conditionally divided into two main classes:
Polymeric on a polyurethane (Hyperdesmo) or acrylic (Weber) basis. They are one-component and two-component, polyurethane spraying technology usually treats surfaces of large areas.
- bitumen water emulsion with mineral, chemical additives and rubbers, mainly for interior decoration;
- solvent-based with added rubbers and minerals;
- hot oxidized bitumen with minerals;
- polymer-bitumen in an aqueous solution of an emulsifier;
- latex-bitumen or so-called liquid (two-component sprayed for large areas) rubber.
For waterproofing and protection of other moisture-proof materials, a profiled Planter membrane is attached to the outer vertical walls of basements. The material is a high-density polyethylene (HPDE) sheet with molded round protrusions 7. 5 – 8 mm high. The maximum length of Planter rolls is 20 m with a width of 1.2 or 3 m.
Also for underground waterproofing, special PVC membranes made of extruded polyvinyl chloride (Ecobase V) are used, which have low UV resistance. The length of this type of roll reaches 30 m, the width is 1 – 2.5 m.
There are two main varieties of dry cement waterborne waterproofing.
These are rigid deep penetration compounds (Ceresit, Dehydrol 5) and elastic with the addition of latex (Penecrit, Dehydrol 7). The first group of materials is used to protect large areas from moisture, and elastic compounds close up the input holes, seams, and also repair large cracks with their help.
Impregnations for concrete, depending on the chemical composition, work in two main directions. Water repellents form a water-repellent film on the concrete surface, and clogging compounds (Kontacid 3, Dehydrol 10-2) fill its pores.
It should be noted that bridging impregnations are capable of penetrating into the concrete structure at distances of up to 400 mm, while the maximum efficiency of the water-repellent properties of concrete is achieved at a bridging depth of 150 mm.
Impregnation materials can be added directly to the concrete prior to pouring or used for post-treatment of its surface.
Silicate and organosilicate compositions are currently produced, the latter having the best efficiency. The main component of bridging impregnations is silicate liquid glass, which is able to independently perform these waterproofing functions.
For injection of high pressure waterproofing mixtures into the concrete structure, materials with high fluidity are used. The main types of injection formulations:
- acrylate two- and three-component gels;
- Foaming and non-foaming silicate resins;
- microcements in aqueous and polymeric solutions;
- two-component epoxy resins;
- one-component and two-component polyurethane resins.
Conventional plaster waterproofing is a conventional cement-sand composition for leveling walls with special additives. The latter are:
- seals made of ferric chloride, sodium aluminate, liquid ceresite, bitumen;
- latex with a content by weight of not more than 5%;
- liquid glass in an amount not exceeding 2.5% by weight.
There are special plaster mixes for gunning (spraying) based on colloidal cement mortars with finely ground fillers and traditional sand.
Protection of the basement floor from inside from ground water
Waterproofing of the basement floor from ground water can be carried out at the stages of pouring the concrete foundation slab and / or before laying the floor coverings.
In the first case, it is more efficient to carry out with the help of rolled materials or profiled membranes – Planters.
Floors inside cellars, given that groundwater has a higher pressure than capillary water, should be protected with materials that have high adhesion (adhesion) to concrete. This is primarily cement-based deep penetration waterproofing, impregnation.
In particularly difficult cases with high humidity below, it is possible to use bitumen-based roll materials (PVC membranes). They are glued to the floor with a direction on the walls or using bituminous mastics. Next, the rolls are covered with a screed with a reinforcing cage, which is subsequently coated with deep penetration cement waterproofing.
Basement waterproofing technology from groundwater
The main problem faced when protecting basements from groundwater is their high pressure.
Therefore, waterproofing inside the basement against groundwater must have high adhesion to the concrete surface so that it does not peel off from the walls under external pressure.
These conditions are best met by deep penetration cement compositions, which are applied using the following technology:
If the waterproofing of the basement from the inside from groundwater must have good adhesion with concrete, then for the outside, due to the direct pressure of water masses on the walls, this requirement is not so essential. Therefore, for external waterproofing of basement walls, a wide range of materials from bitumen rolls protected from damage by mastics, liquid rubber, membranes and the same cement compositions can be used.
It is clear that if an ordinary consumer turns to specialists from specialized companies, which, for example, work for IC Stroyizolyatsiya, then the likelihood of errors during waterproofing work will be reduced to zero. Troubles in connection with waterlogging in basements are much more likely to occur if the owners trust their waterproofing to irresponsible builders or do it themselves.
Here are some examples of the most common mistakes made by non-specialists when waterproofing themselves:
- Priming of walls in case of penetrating waterproofing of the basement from the inside from groundwater. The bridging composition simply will not seep through the dried primer, which has clogged all the pores.
- Waterproofing basement walls from the inside from groundwater without sealing joints between concrete blocks, floors, walls and wide cracks according to the correct construction technology (with chasing of channels and puttying them with elastic waterproofing).
- Waterproofing of a concrete basement from the inside from groundwater with deep penetration compounds without further wetting.
- Application of bituminous, polymeric mastics on underground walls without their protection (Planter, polystyrene foam insulation).
- No priming of the walls with primers before laying the external rolled waterproofing or too high humidity of the concrete surface during the application of the compounds.
External and internal waterproofing of the basement from groundwater is carried out according to different technologies using materials, the choice of which should correspond to the tasks being solved.
At the same time, for obtaining high-quality and durable waterproofing, there is such a wide range of technical solutions that only specialists with significant experience can choose the best option. The greatest chance to meet such employees is to contact a specialized company, one of which is Stroyizolyatsiya IC.
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External waterproofing of buildings and structures, foundations and wells
Structures buried in the ground (foundations, cellars, ground floors, channels, etc.) are regularly in contact with moisture. Therefore, they need reliable waterproofing that will last a long time. If the waterproofing of the underground part of the structure is performed poorly, in violation of the technology, then quite soon a number of problems will arise, including:
- corrosion of internal elements made of metal, reinforcement
- destruction of the concrete structure and reduction in the strength of the supporting structure
- reduction in service life of communications
- the need for additional construction or unplanned repair of an existing hydro-barrier.
In the exploited underground parts of the building (basements, basement floors), waterproofing is arranged both outside, to protect against groundwater, and from the inside – against capillary moisture. By the way, a hydro-barrier inside such premises is not just the protection of construction materials, but also a matter of people’s health, because high humidity in tandem with insufficient ventilation creates ideal conditions for the appearance of fungi and mold.
The Technoprok company offers various materials for waterproofing the buried parts of the building from the outside and from the inside. Here are the most popular ones for waterproofing large areas outside:
Liquid rubber TECHNOPROK R (Russia)
Water-based bitumen-polymer emulsion
Universalna liquid rubber (Russia)
Water-based bitumen-polymer emulsion 9 0005
Liquid rubber of Light category (Russia)
Water-based bitumen-polymer emulsion
External waterproofing of foundations and wells
Bituminous polymer emulsions “Rapidflex”, “Technoprok”. Applied using an airless spraying machine, after drying, they create a seamless, elastic membrane on the treated surface with such characteristics as absolute moisture impermeability, the ability to self-repair.
- With direct water pressure
One-component mastic “Elastopaz” on a bitumen-polymer basis. A popular solution for do-it-yourself waterproofing. The mastic is ready for use, applied manually with a rubber scraper or spatula. The recommended approach is to apply in two layers (the second layer is applied only after the first has completely dried).
The use of Elastopaz mastic for external waterproofing is justified by the fact that this material is ideally suited for direct water pressure. Water from the outside (from the street) tries to penetrate into the underground part of the building, and protection from Elastopaz “gets up” on its way. With a large volume of water, its pressure can be significant and this would be enough to literally break the waterproofing.
But behind the Elastopaz mastic there is a wall that water cannot destroy. And this wall supports the membrane from behind, prevents mechanical damage to the waterproofing due to water pressure. Thus, a kind of symbiosis takes place: the Elastopaz film protects the wall from water penetration, and the wall holds the film under direct water pressure.
- With back water pressure (e.g. well)
With water back pressure, a pressure wall must be built to apply Elastopaz. This is exactly what they do when they use Elastopaz to waterproof basement walls from the inside. In this case, water penetrates through the wall and literally tears Elastopaz off the wall. To prevent this from happening, a new wall is being built behind the waterproofing, which will “support” it, hold it under the back pressure of water.
It is much easier in such a situation (for waterproofing from the inside of the underground part of the building) to use Plombizol dry waterproofing mixtures. They work great under back pressure.
The innovative expanding material “Plombizol” is also used on a small area to create a hydro-barrier from the outside, but again, in the presence of back water pressure. A classic example is a well, which is assembled from concrete rings.
Two problems are possible in this case:
- The water from the well may go out, the well will dry up.
- Water from outside (not always clean) with soil impurities can enter the well.
Obviously, the water pressure from the inside is greater than from the outside, especially if the well is deep. Therefore, Elastopaz mastic should not be used for external waterproofing of an underground structure of such a small area. The best solution would be to lay hydraulic seals (pressure Plombizol) outside in all the seams between all concrete rings, then apply strips of expanding Plombizol on top.
To summarize: for external waterproofing of small areas of underground parts of buildings and structures with direct water pressure, Elastopaz mastic is used, and with reverse fluid pressure (for example, a well), Plombizol dry waterproofing mixtures should be used: pressure and expanding.