What is waterproofing of a strip foundation and how to do it correctly, basic methods and options

The robustness and longevity of foundations are essential when using concrete in construction. Waterproofing is a crucial component of foundation construction, particularly for strip foundations. Waterproofing a strip foundation is stopping water from seeping into the building, which over time can cause problems like mold growth, dampness, and even structural damage.

What precisely does waterproofing a strip foundation entail, then? To put it simply, it’s the act of utilizing materials or methods to build an impermeable barrier against the infiltration of water. This barrier is necessary because improperly managed seepage of rainwater and groundwater into the foundation can cause issues.

Strip foundations can be waterproofed using a variety of techniques. Liquid waterproofing membrane application is one popular technique. Usually, these are put straight onto the foundation’s outer surface prior to backfilling. Liquid membranes offer a seamless water barrier that sticks to concrete well.

Using paints or coatings that provide waterproofing is another successful strategy. These coatings are made with a unique formula that can tolerate soil pressures and offer a flexible, long-lasting barrier against moisture. They frequently include additives that improve adhesion and UV radiation resistance, and they are applied in layers to guarantee total coverage.

Installing a drainage system in addition to waterproofing can be advantageous in situations where more protection is required or in more difficult conditions. Installing a perimeter drain or a French drain around the foundation may be part of this. By collecting and rerouting water away from the foundation, these systems lessen the chance of water intrusion and lower hydrostatic pressure.

For strip foundations to be effectively waterproofed, preparation is essential. The foundation should be examined for cracks, voids, or other flaws that can jeopardize the barrier’s integrity before using any waterproofing materials. To ensure a smooth and even surface, these should be repaired using the appropriate concrete repair products.

To sum up, waterproofing a strip foundation is an essential step in guaranteeing a building’s long-term stability and longevity. Builders and homeowners can safeguard their investments from water-related damage by knowing the fundamental techniques and choices that are available. The objective is always the same, whether drainage systems, coatings, or liquid membranes are used: to build a sturdy barrier against moisture and maintain the structural integrity of the building for many years to come.

Is it necessary to waterproof a strip foundation

Nowadays, all kinds of strip foundations used in building are either entirely or partially composed of concrete. Because of its porous composition, concrete actively absorbs water.

Water solidifies in the monolith’s pores at below-freezing temperatures, destroying it from the inside out and resulting in chips, cracks, delamination, total deformation, and destruction.

A strip foundation that has been waterproofed allows the monolith to be shielded from moisture and water. In this instance, it is feasible to greatly extend the building’s useful life, enhance its quality, get rid of the chance of mold and mildew growing within the structure, prevent shrinkage, cracks, and deformations in the foundation structure, and stop the corrosion of metal components.

Regardless of the groundwater level, soil type, structural characteristics of the foundation, or materials used in its construction, foundation waterproofing measures must always be implemented.

But a number of considerations go into the selection of a particular waterproofing material and protection technology.

It’s important to realize the importance of strip foundation waterproofing in preventing water damage to structures. This procedure entails using materials or methods to stop water seepage into the foundation, which over time could erode the structure of the building. A strip foundation must be properly waterproofed using a variety of techniques, including coatings, membranes, and admixtures in concrete mixtures. Depending on the local climate and soil type, each method has pros and cons of its own. Waterproofing is a crucial factor to take into account in construction projects because it can guarantee the longevity and durability of the structure against problems caused by water if the proper waterproofing method is chosen and applied.

Differences between a shallow and a conventional foundation

When it comes to the installation of insulation, these kinds of foundations hardly differ at all. The areas treated with compounds, the quantities of materials used, and the total amount of time spent on each task are the only variations. The only way a shallow strip foundation varies from a conventional one is in the depth of immersion; otherwise, the work carrying technology is identical.

It is important to keep in mind that variations in the concrete structure’s depth of immersion correspond to discernible variations in the density of the monolith’s contacts with soil moisture. A traditional strip foundation is lowered to a level that is lower than the boundary where soil freezes. The foundation is situated in a more challenging area and is subject to rain, recurring inflows of melted moisture, and variations in water levels.

Consequently, when it comes to waterproofing, better materials and cutting-edge technologies are used in this instance than when treating shallow structures.

Waterproofing methods

A strip foundation can be waterproofed primarily in two ways: horizontally and vertically. Each method uses a particular technology and set of materials.

Horizontal

It is imperative to consider waterproofing a horizontal strip foundation during the structural design phase. On top of the main work, preparatory activities can take up to 17 days. The foundation in the corresponding plane is shielded from capillary groundwater by horizontal insulation. consists of a drainage system that is inherently supplied with high groundwater levels.

Under the tape, a sturdy foundation is created, and a waterproofing layer is applied on top of it. They frequently make a pillow that is thicker than the intended foundation for this reason. The simplest option—making a screed out of cement and sand at a 1:2 ratio—is good for a bathroom, garage, etc.

• Filling the bottom of the pit with sand in a layer up to 30 centimeters thick, ramming.
• Pouring the cushion with a cement screed in a layer of 6-8 centimeters, hardening within 2 weeks.
• Coating the screed with bitumen mastic, installing roofing felt sheets on top of the bitumen layer, repeating the layers of mastic + roofing felt. Pour a cement screed on top in a layer of 6-8 centimeters, hardening.
• Construction of the foundation.

In certain situations, drainage might be required, such as when the structure is buried below or at the level of groundwater or when the soil has a low permeability and moisture buildup potential.

• 100 centimeters from the base around the perimeter of the structure, they dig a pit up up to 30 centimeters and more depth than the depth of the foundation, 25 centimeters. The foundation pit must have a slope towards the water collector, where the water will accumulate.
• Coating with a layer of geotextiles of the bottom with an overlap on the walls by at least 60 centimeters.
• A layer of gravel is laid 5 centimeters thick.
• Installation of a drainage pipe with a slope to a water collector equal to about 5 mm/1 POG.m.
• Puffing a pipe with a layer of gravel 25 centimeters, wrapping a sandwich left earlier than the edges of geotextiles, backfill.

Such occurrences eliminate the chance of a pipe blockage by allowing water to enter it. The water collector will receive unrestricted moisture.

Vertical

Different base wall materials must be processed in order to waterproof the strip foundation in this manner. Both during the building’s construction and after it is finished, work can be done. Furthermore, there are two types of vertical water insulation: primary (which occurs when specific hydrophobic additives are used during the building process to strengthen the concrete’s resistance to moisture) and secondary (occurs if the first type of insulation is not implemented).

Vertical waterproofing can be either internal or external, depending on where the arrangement is located. Plaster, coating compositions, paint and varnish coatings, adhesive materials, antiseptics, biocides, and other sealing impregnations are used to carry out the task. d.

• When the base is affected by moisture from the soil, which is retained in the soil by adhesive or capillary forces and remains there constantly, regardless of the levels of underground, filtration water.
• If melt and rainwater fills the pores in the soil and gets deep into the ground, seeping to the depth of the foundation.
• When the surface layer of underground moisture lies close.

To reduce the impact of water that has risen through the capillaries, the foundation’s above-ground portion is typically insulated in addition to its subterranean portion.

Which method is the most optimal

In response to the question of whether waterproofing a strip foundation is necessary or desirable, skilled artisans assert that both kinds are required.

Only in this scenario can we ensure that the building will last a long time and that there won’t be any structural damage.

Insulation of a pile-strip foundation

Two phases comprise the work: first, all piles must be expertly processed, and then they must be covered with an insulating layer of tape. The supports are protected using a variety of techniques and materials: driven piles can be covered when practical, and bored piles can be poured into tubes composed of a particular waterproof material. However, modern supports are typically made by manufacturers using concrete that is resistant to moisture (with specific additives), so they are not concerned about moisture.

You have additional options for processing tape, such as coating (bitumen, tar), rolling (roofing felt), spraying with a mixture of rubber and bitumen, employing polyurethane foam, etc.

The selection of material is based on various factors such as cost effectiveness, protection requirements, foundation structural characteristics, and technology implementation feasibility.

How to ensure the protection of the foundation from moisture

Waterproofing around a strip foundation needs to fulfill the same standards as it does anywhere else: it should prevent water from penetrating the concrete and destroying it, balance out seasonal temperature fluctuations, and last a long time.

Main types of waterproofing

There are just two kinds of work: vertical waterproofing of the foundation walls and horizontal insulation, which entails applying a layer during the building stage of the structure to protect against subsurface moisture. Drainage is a different subtype that is prepared for the most challenging situations.

While some waterproofing techniques can be completed at home by one person, others call for the use of specialized tools, industrial machinery, training, and experience.

Carrying out waterproofing during laying

Waterproofing occurs in multiple steps when laying a strip foundation.

• Formation of a sand and gravel cushion at the bottom of the trench with a layer up to 30 centimeters thick, ramming, leveling.
• Laying a concrete screed with a layer up to 8 centimeters, after 14 days, treating the surface with molten bitumen or mastic based on it, installing a layer of roofing felt, again passing bitumen and again roofing felt. On top, again pour concrete up to 8 centimeters thick.
• Carrying out further construction work after 14 days.

Waterproofing after the construction of the foundation

Different materials can be used to waterproof the foundation once the tape is ready. This can be carried out both during and after the foundation is built. The easiest way is to apply one or two layers of molten bitumen or mastic based on it entirely over the tape. Additionally, roll materials are used in the technique of spraying different compositions.

Drainage

Drainage is carried out in situations where groundwater levels are high. In this instance, waterproofing is insufficient to keep the foundation safe from water, so a network of subterranean channels is built to drain extra moisture. In soil that is heaving, drainage is essential.

The process is straightforward: they excavate a ditch around the entire base, create a cushion out of large crushed stone or broken brick, place drainage pipes at an angle on top, and then cover everything with geotextiles. Water is removed from the site after being drained into wells that have been specially constructed.

Blind area

Along the whole perimeter of the building, there is a blind area designed to shield the foundation from precipitation and melting water. The blind area is a narrow strip of concrete that is angled from the outside of the building to the building walls by a degree or two.

Soil is chosen surrounding the structure in a layer as deep as fifty centimeters and as wide as thirty centimeters beyond the roof overhang in order to create a blind area. In the trench, a cushion of sand and gravel is created before it is leveled and rammed. On top, a minimum 5-centimeter-thick layer of concrete screed is poured. About 10 centimeters should be the width of the screed if you intend to walk on the blind area.

What materials should be used

The design characteristics of the foundation and the building as a whole, the kind of soil, the operating environment, etc., are all important considerations when deciding whether or not to waterproof the strip foundation and how best to protect it. There are a lot of materials available now, so it won’t be hard to select the best one.

• Roll (aka adhesive) – produced in the form of films, membranes, bitumen sheets, mounted on a layer of mastic or by heating, planting on glue (already applied to the sheets).
• Coating – bitumen, cold mastics, various compositions for application in liquid form with subsequent hardening.
• Penetrating – sprayed or applied with a brush, absorbed into the concrete monolith with subsequent crystallization and filling of its pores, which makes the concrete resistant to moisture.
• Injection – similar in action to penetrating, applied by drilling holes in the concrete and subsequent distribution of the composition under pressure, due to which the monolith is impregnated and strengthened from the inside.
• Paint – liquid polyurethane foam, liquid rubber can be used, which completely harden after application and create a water-repellent elastic film. They do not last long, but are easy to apply.

Types of insulation

Waterproofing comes in a variety of forms. Making the right choice at the selection stage is crucial, and you shouldn’t skimp on the materials’ quality.

Bitumen coating

This is the most widely used, least expensive, and fastest method. Completely covering the foundation walls is mastic made of bitumen, which seals pores, chips, and microcracks to keep moisture out.

Waterproofing coatings based on bitumen can be either single-component (a heated block of bitumen) or multi-component (supplied in a container, a chemical reaction takes place and the mixture takes on a liquid consistency after mixing).

Before beginning work, the monolith is carefully dusted and brush-cleaned of dirt. The composition is then applied to the foundation’s surface. This kind of waterproofing is reasonably priced, all work is doable independently, and in five to seven years, the layer will need to be updated (roll waterproofing can be installed from above; no repair is assumed).

Roll waterproofing

Not a very costly option either. The most widely used technique is thought to be roofing felt installation. Sheets made of aquaisol, isoelast, and other materials are also possible. They apply to waterproofing roofs, pools, and other structures of any kind. They shield concrete from various stresses, such as high groundwater pressure. Homes without a basement must be waterproofed both horizontally and vertically.

• Floating – before application they are heated (using a burner), then glued to the concrete monolith and wait for hardening.
• Glued – mounted with a composition based on bitumen or other adhesive substance. There are materials already with a self-adhesive layer, which are applied quickly and easily.

Roll materials’ primary benefits include their low weight and ease of installation, long lifespan, superior water-repellent qualities, high mechanical strength, and dependability.

The technique is very straightforward: first, prepare the surface (it needs to be clean, dry, and smooth), then apply a layer of bitumen (self-adhesive films and fusion materials are immediately mounted on the base), glue the roll material at the joints with a 15-centimeter overlap, and finally weld with a gas burner.

Waterproofing with plaster compounds

Moisture-resistant components are present in plaster mixtures. The mixture needs to be prepared as per the directions, then applied to the foundation using a regular spatula and pre-sheathed with a unique plastic mesh. The primary benefits of this approach are its low cost, service life of 10 to 15 years, and speed and ease of work execution. However, the plaster exhibits far from maximum moisture resistance, and microcracks can form in it.

Use of liquid rubber

With a roller, brush, or specialized sprayer, the composition is applied to a surface that has already been primed. provided in a ready-made configuration. The composition often expires quickly after being opened; it needs to be used right away. Long-lasting up to 50 years, simple and easy to maintain, and guaranteed to have extremely high waterproofing qualities.

Frequently, using a specialized sprayer is required to complete the task, which adds complexity, particularly if everything must be done by hand. The compositions are not very well-liked on the market right now because of their high price.

Penetrating waterproofing

The priciest and most efficient way to waterproof a strip foundation—or any other foundation, for that matter. Cement, quartz sand, and unique additives are the main ingredients used to prepare the penetrating mixture. The procedure is comparable to plastering walls; certain compositions can be sprayed on or applied with a brush. Once the layer is finished, the concrete monolith is strengthened and liquid-repellent crystals are formed.

The material’s primary benefits are its superior protection, total lack of seams, ease of application, versatility, and safety for human health.

Shielded waterproofing

This approach is hardly ever used. The installation of the protection works on this principle: using a special mounting gun, water-repellent mats are affixed to the foundation surface. Additionally, panels can be fastened and inserted into the edge-located locks. It is not feasible to complete this kind of work on your own; experts, if licensed, handle the entire process.

Horizontal waterproofing

This kind of defense is intended to shield the structure and foundation from the damaging effects of capillary moisture. On the concrete’s surface is a strip of material that extends 15 centimeters past the walls’ boundaries. The tape can be applied as a base or as a covering layer on top of a mastic or other composition, or it can be laid independently without being fastened.

Sprayed insulation

New constructions are protected by modern technology, which is also utilized to repair outdated waterproofing coatings. The method’s primary benefits are its ease of use and quick task execution, long service life, total lack of seams in the layer, quick hardening, safety for human health and lack of harmful substances in the composition, resistance to UV light, and elasticity.

We can only list the high cost of this kind of protection as a drawback because it will require specialized equipment to do the job.

Sequence of work

The work is done in accordance with the same principle regardless of the material selected.

• Choosing the material and the method of its application
• Thorough preparation of the surface – drying, cleaning, leveling
• Application of a preparatory layer (not all methods require this) – coating with mastic, glue, priming concrete, etc.d.
• Installation of waterproofing material – spraying, pasting, distribution with a brush or roller, fastening in other ways
• Waiting for complete drying/hardening
• Applying a second coat (if technology provides for it)

A strip foundation’s ability to withstand water damage is essential to any building’s longevity and stability. The process of waterproofing a foundation is to stop water from seeping through and causing damage over time. This can be accomplished in a number of efficient ways, each with unique benefits based on the particulars and specifications of the building site.

Applying a waterproof membrane straight to the foundation’s exterior is one often utilized technique. This membrane functions as a barrier against water infiltration and is frequently composed of bitumen or synthetic materials like PVC or EPDM. In order to prevent any gaps or overlaps where water could seep through, it is applied in layers. This approach is well-liked by builders because it is very efficient and reasonably simple to use.

Using liquid coatings or waterproofing compounds is an additional strategy. They are applied to the foundation’s surface in a manner akin to painting. When they are dry, they create a seamless, flexible waterproof layer that clings firmly to the concrete. This technique has the advantage of being simple to apply and having the capacity to cover details and uneven surfaces, like pipe penetrations, without the need for seams.

For the best waterproofing, a combination of techniques may be used in some circumstances. For example, improved protection against water intrusion can be achieved by combining a liquid waterproofing compound with a waterproof membrane. In order to divert water away from the building and avoid hydrostatic pressure buildup that can jeopardize the waterproofing, adequate drainage around the foundation is also crucial.

In the end, the best waterproofing technique will depend on a number of variables, including the building’s intended use, the local climate, and the state of the soil. It is advisable to seek advice from a qualified waterproofing specialist or contractor to make sure the chosen approach is appropriate and carried out correctly. Your building’s structural integrity can be preserved for many years and water damage can be prevented by making an investment in efficient waterproofing for your strip foundation.

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