One of the most important steps in creating a long-lasting and energy-efficient home is insulating a strip foundation. In addition to preventing heat loss, proper insulation also guards against moisture and prolongs the life of the foundation. You may dramatically increase your home’s efficiency and comfort by taking the time to insulate your strip foundation on the inside as well as the outside.
With the correct supplies and a little know-how, you can tackle the seemingly difficult task of insulating a strip foundation on your own. Comprehending the procedure and the materials required is essential for a successful project, regardless of whether you’re renovating an old foundation or building a new one. Every stage matters, from selecting the appropriate insulation type to guaranteeing correct installation.
We’ll walk you through the fundamentals of insulating a strip foundation in this article. We’ll go over the various materials available, their advantages, and the detailed steps involved in ensuring a comprehensive and efficient insulation job. You can improve the overall energy efficiency of your home and shield your foundation from the weather with these useful tips.
- Is it necessary to insulate a strip foundation
- Features of insulation
- Internal thermal insulation
- External insulation
- Types of thermal insulation for foundation strip
- Use of polystyrene foam
- Polystyrene foam boards
- Insulation with penoplex
- Use of polyurethane foam
- Insulation with expanded clay
- Technology of insulation of strip foundation with your own hands
- Insulation of a shallow foundation strip
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Is it necessary to insulate a strip foundation
An increasing number of people are asking how to insulate a house’s strip foundation from the inside out. There is no longer any reason to doubt the necessity of insulating the foundation. Ultimately, the foundation was built with reinforced concrete, which has a high degree of thermal conductivity.
It efficiently transfers heat from the street to the room during cold weather, especially if the foundation is shallow and may even collapse due to soil heaving without insulation.
A strip foundation needs to be insulated for the following main reasons:
- Reducing the freezing of the soil near the base of the house – as a result, increasing the strength and durability of the entire structure
- Reducing heat loss in the room – accordingly, and the cost of heating the entire building
- Elimination of the risk of condensate in the basement, which often causes dampness, spread of fungi, mold, etc.d.
- Ensuring comfort – it"s nice when the floors in the room are warm, not icy at any air temperature
Features of insulation
An insulated strip foundation is a base that is shielded from the elements both internally and externally through the use of carefully chosen materials, accurate calculations, and adherence to work-related technology.
Internal thermal insulation
It’s important to thoroughly research the matter before insulating a strip foundation inside a home. Typically, the work involves the use of polystyrene foam boards, which are placed on the ground to fill in the gap that appears between the floor and the ground. When there is no basement and the foundation is poured at a shallow depth, internal insulation is installed (usually these are shallow foundations).
While heaving or freezing of the soil can be addressed and the room protected from below, temperature fluctuations cannot be prevented from the base by insulating the foundation from the inside. That’s why external thermal insulation work is typically done in conjunction with it. Once the layer of thermal insulation has been laid, building materials are stacked on top and the building’s construction process proceeds.
External insulation
The first step in external work is to dig a 5–15 meter-deep trench around the building’s whole perimeter. After that, a sand cushion is added to the pit, and thermal insulation materials—typically polystyrene foam boards—are installed and sealed with mastic. The layer’s strength and impermeability may be compromised by the application of mechanical techniques. After that, sand or expanded clay is poured into the trench.
Plastering the portion of the strip foundation that is above ground completes the external thermal insulation of the foundation.
Benefits of using insulation to protect the foundation from the outside:
- Protection from freezing
- Giving frost resistance and moisture resistance to the foundation
- Creating a barrier for rain and groundwater
- Protection from external mechanical influences
- Creating an optimal microclimate in the building
Types of thermal insulation for foundation strip
No matter what type of insulation is used, the strip foundation needs to be properly protected with premium materials. Numerous factors are considered when making the decision, including the soil’s properties (such as the depth at which it freezes), climate, structure, etc.
Use of polystyrene foam
Foam plastic slabs exhibit a thermal conductivity level between 0.03-0.04 W/m0K and are manufactured in compliance with GOST 15588-86. Waterproofing is required even though foam plastic is not afraid of water because the material is only partially waterproof. The slab has a 25-year lifespan on average, after which it may start to deteriorate. This will not have an impact on the thermal insulation layer’s quality.
Sand and dry soils can be covered with foam plastic; soil with average humidity levels require the installation of a thick layer of thermal insulation that is also sealed off from the outside. It is preferable to use a different type of thermal insulation material rather than polystyrene foam if the soil is heaving and damp. In the initial years, foam plastic may collapse due to mechanical loads influencing the shrinkage process.
Polystyrene foam has good thermal insulation qualities; a 50 millimeter thick slab performs similarly to 100 millimeter thick layers of mineral wool, 190 millimeter thick layers of wood, and 850 millimeter thick layers of brickwork. For both conventional and shallow strip foundations, the thickness of the thermal insulation layer is chosen on an individual basis.
A slab of 50–75 millimeters is appropriate if the winter temperature falls below -20C; if it falls below -30C, it is preferable to take 100 millimeters. Strip foundations in the north must be insulated from the outside using slabs 150 millimeters thick due to technological constraints.
For capital structures buried below the freezing point of the earth, polystyrene foam is perfect. Different materials are used for shallow foundations. The installation of insulation reaches the freezing point.
Polystyrene foam boards
Polystyrene foam insulation is the best choice for the foundation. The material has a very high mechanical strength index and a lower thermal conductivity coefficient than foam plastic. The insulation’s unique closed-cell structure makes it an effective waterproofing agent as well. does not take in moisture or allow water to pass through. Compared to foam plastic, the polystyrene foam layer can be thinner (a difference of 70 and 100 millimeters can achieve the same outcome).
Special joint grooves along the edges make it simple and quick to lay the layer. They promise even more constriction.
Insulation with penoplex
One of the best and least expensive insulation materials is penoplex. Penoplex is a contemporary material composed of foamed polymer and having an entirely enclosed air-filled cell structure. Penoplex exhibits maximum thermal insulation qualities and minimal water absorption as a result.
The material is resistant to a range of impacts and does not fear mechanical damage. It can function both inside and outside the foundation as an insulating layer. Penoplex is supplied as slabs with mounting grooves that come in varying thicknesses. This allows for quick and easy application of a layer of penoplex without the need for cold bridges, gaps, or seams.
The thermal insulation layer in the base is additionally reinforced with special dowels to ensure the foundation’s long-term durability. On a surface that has been prepared with glue, internal thermal insulation of a strip foundation using penoplex is also carried out.
Use of polyurethane foam
Insulation made of polyurethane foam is a relatively new development. Though it assumes a higher density, its characteristics are similar to those of extruded polystyrene foam. The material guarantees that the thermal insulation layer is completely tight, that there are no joints or gaps, and that it is impervious to moisture.
Although the foam is rather expensive, its high quality and ease of use make it worthwhile because you can totally stop the walls from freezing. Furthermore, applying a layer of waterproofing is not necessary. All that needs to be done to coat the monolith is a unique primer, followed by a continuous layer of foam spraying.
Insulation with expanded clay
Strip foundations are frequently insulated using expanded clay. The substance is coarse sand, with particles as large as 5 millimeters in diameter or as small as 20–40 millimeters in granules. It is made by first foaming a particular kind of clay and then firing it in ovens. Cheap, lightweight, and porous is expanded clay.
Since the material readily absorbs moisture, does not rot, and is unafraid of vertical and lateral loads, it is typically not placed in the ground when carrying out other kinds of work.
It is essential to insulate a strip foundation in order to shield your house from moisture, temperature changes, and energy loss. Using easily accessible supplies and equipment, this article walks you through the process of insulating a strip foundation’s exterior and interior. You’ll discover how to do it yourself step-by-step, guaranteeing that your foundation is sturdy, dry, and energy-efficient all year long. Our helpful advice and clear directions will assist you in achieving expert results whether you’re taking on this project for the first time or want to hone your skills.
Technology of insulation of strip foundation with your own hands
While there are several materials that can be used for strip foundation insulation, extruded polystyrene foam or penoplex slabs are the best options. The technology allows for independent completion of all tasks.
How to use your hands to manually insulate a strip foundation
- Preparation of the site – clearing the sinuses of the pit with a shovel, constructing passages and a platform for work. The foundation is dried, it is necessary to clean the area around the foundation by 1-2 meters.
- Protection and strengthening of concrete – with a primer applied with a roller, followed by waiting 24 hours.
- Preparation of the material – cleaning the slabs with sandpaper to improve adhesion to concrete. Sheets can also be primed.
- Laying slabs – regardless of whether the base is insulated with penoplex or technoplex, for these purposes in the summer it is better to choose a special mixture with microfibers (in a container of 25-30 kilograms), in winter foam. Sometimes the slabs are sealed with mastic or rubber-based glue, which is applied to the sheet and attached to the concrete wall with plastic dowels. Insulate in the ground to a depth of 60 centimeters, with sheets up to 60 millimeters thick, completely covering them with glue.
- Backfilling of the soil – is carried out after fixing the insulation, very carefully, in layers of 30 centimeters, with ramming.
Insulation of a shallow foundation strip
In this instance, the soil freezing level is normally found beneath the building’s foundation. Thus, insulation is applied both horizontally (internal) and vertically (external). The most common material used for thermal insulation is extruded polystyrene foam.
Work-related technology:
- Digging a trench to a depth that reaches the cushion under the sole of the foundation to a width that is calculated using the formula: the depth of the average annual freezing of the soil plus 5 centimeters.
- Application of adhesive or coating waterproofing material to the vertical surfaces of the foundation (or to the wall of the basement, if there is one). For these purposes, bitumen emulsion can be used.
- Filling the pit with a gravel-sand mixture, which becomes an extension of the cushion under the sole.
- Fastening the heat-insulating material slab to the heated surface using mastic or glue.
- Covering the insulation with geotextile or thick film so as not to damage the integrity of the layer.
- Next, the insulation slabs are laid on the cushion in the pit, a drainage system is made and the rest of the gravel and sand mixture is filled in. A blind area is poured onto it at an angle. Drainage is corrugated pipes combined into a system that help protect the insulation layer from moisture.
Topic | Details |
Materials | Use extruded polystyrene foam for external insulation due to its moisture resistance and durability. For internal insulation, consider using polyurethane foam which offers good insulation properties and easy application. |
Preparation | Clean the foundation surface thoroughly to remove dirt and debris. Ensure the surface is dry before starting the insulation process to ensure proper adhesion of materials. |
External Insulation | Apply a waterproofing layer to the foundation. Attach the extruded polystyrene boards using a special adhesive. Cover the insulation with a protective layer, such as a drainage board, to prevent damage. |
Internal Insulation | Spray polyurethane foam directly onto the inner surface of the foundation. Make sure the application is even and covers all areas. Allow it to cure completely before proceeding with any additional work. |
Finishing | For external insulation, consider adding a plaster layer over the protective board for aesthetics and extra protection. Inside, finish with drywall or another suitable material to cover the insulation and provide a clean look. |
A vital step in guaranteeing the longevity and energy efficiency of your house is to insulate a strip foundation on the inside as well as the outside. You can lower your heating expenses and shield the foundation from high temperatures and moisture by properly insulating. The most important thing is to use the right supplies and follow the right procedures whether you are working on this project alone or with assistance.
Foam boards and spray foam are excellent materials for exterior insulation. They offer a strong defense against moisture and cold. The protection of the foundation can be greatly increased by installing a waterproof membrane before insulation and making sure that drainage is adequate. Remember to apply a protective layer to the insulation to keep it safe from UV radiation and physical harm.
By providing an additional layer of thermal protection, interior insulation can enhance the external work. Your crawl space or basement can be made warm and dry by using insulating concrete forms or rigid foam panels. Sealing all seams and crevices is essential to stop air leaks, which can reduce the insulation’s effectiveness.
Recall that thorough planning and attention to detail are crucial. Prior to applying insulation, clean and dry the surfaces. For optimal results, always follow the manufacturer’s instructions. Even though it could seem like a difficult undertaking, you can successfully insulate your strip foundation and take advantage of a more comfortable and energy-efficient home with the right planning and supplies.