Advantages and disadvantages of thermal insulation of the foundation with expanded clay, insulation technology outside and inside the building, recommendations for choosing a quality material. Warming a foundation with expanded clay is a proven method of thermal insulation with an inexpensive porous material. To create a protective layer, granules are poured into cavities along the wall, created using a specific technology. We will talk about the rules for forming the coating outside and inside the building in our article.
Features of thermal insulation of the foundation with expanded clay
Expanded clay is a light free-flowing heat insulator from small fragments, which is obtained after firing clay rocks. Grains ranging in size from 5 to 40 mm are divided into three fractions: 5-10 mm (sand), 10-20 mm (gravel), 20-40 mm (crushed stone). Each type of product is intended for use in certain situations, but any granules are suitable for warming the foundation.
The insulating layer forms an air gap directly near the floor and removes water from it. The grains are used to protect the underground and aboveground parts of the base. To eliminate heat loss, an additional partition is erected next to the wall or a trench is dug, and then the resulting cavity is filled with granules. The thermal insulation of the wall is carried out in parallel with its waterproofing and the construction of the drainage system.
Warming the base with this material is still relevant, despite the emergence of innovative technologies. This is due to the low cost of work and the simplicity of the process. Often, other means are used in parallel to increase the effect.
The scope of application of the product is limited by its high moisture absorption, therefore it is not recommended to fill it in places where groundwater comes close to the surface. As a rule, the foundations of wooden houses, summer cottages and other buildings for which modern means are too expensive are insulated with expanded clay.
Advantages and disadvantages of warming the foundation with expanded clay
The material has characteristics that allow it to be used outside and inside the house. The main advantages of this free-flowing substance are the following qualities:
- The ability to keep warm in all weather conditions.
- It is not afraid of various aggressive environments, does not rot, does not burn, does not collapse when freezing.
- Mice and other rodents do not live in expanded clay.
- Loose material is easy to work with.
- The use of the product to protect the underground part of the foundation prevents the soil from freezing, which excludes distortions of doors and windows. A barrier is also created between the base and groundwater.
- Thermal insulation of the outer part of the base increases the service life of the structure.
- In the composition of the granules there are no impurities that destroy cement.
- Grains that are placed from the inside of the house prevent condensation from forming in the basement.
- Work can be carried out at any stage of building a house.
Owners should be aware of the disadvantages of using porous material in construction:
- The insulating baffle is much thicker than the pie of today's similar products.
- We must be prepared for substance overruns.
Foundation insulation technology with expanded clay
Thermal insulation is performed in several stages. First, the amount of material is determined and the issues of choosing a product are resolved, then the main operations are carried out.
The choice of expanded clay for basement insulation
To effectively insulate the foundation, the product must comply with GOST 9757-90. It is impossible to check its properties without special equipment; it is possible to determine a fake only by indirect signs.
Make sure the packaging contains the following specifications:
- Thermal conductivity - 0, 06 W / m *OC or below.
- Density - up to 250 kg / m3.
- The granule size is medium or large.
- Water absorption - no more than 20%.
- Frost resistance - at least 25 cycles.
You can demand from the seller a certificate of conformity, which confirms its main characteristics.
Tips to help you buy a quality product:
- When buying expanded clay in containers, first of all, check the packaging. It must be factory-made, without gaps. The bag is light, clean on the outside. The presence of brown or red spots indicates that there is a lot of dust in the container and a large number of damaged grains.
- Open a couple of bags and check the appearance of the pellets. High-quality fragments have the correct shape, there is no abrupt change in geometry. Only such grains provide the permissible density and thermal conductivity. Asymmetric samples indicate a violation of manufacturing technology and low product parameters.
- Do not buy a product if small and large items are mixed. Unsorted products are also not suitable.
- Expanded clay is not particularly durable, therefore, the presence of spoiled grain is allowed - no more than 5% of the volume of the bag. A large amount of crumbs indicates improper storage or careless transportation of the product.
- Moldy granules or fungus indicate the presence of substandard additives in the raw material.
- Check the moisture content of the material. The fragments must be perfectly dry.
- If you buy a bulk product, make sure it is stored in a dry place. It is better to refuse grains that lie in the open air.
- Buy products from well-known manufacturers. If you are interested in insulation from an unknown company, collect as much information as possible about it. The information of interest is on the construction forums.
- Give preference to large construction firms. For information: the cost of imported products is 4 times higher than domestic ones.
The calculation of the amount of expanded clay is based on the requirements of SNiP 23-03-2003 "Thermal protection of buildings". The thickness of the insulator layer h2 is found from the basic formula for determining the heat transfer resistance R: R = h1 /? 1 + h2 /? 2, where h1 is the width of the foundation; ? 1 - coefficient of thermal conductivity of the base material; ? 2 - coefficient of thermal conductivity of expanded clay.
For example, let's calculate the thickness of the insulation layer on a reinforced concrete strip foundation. Construction is underway in the Moscow region. In the reference books we find the values of the coefficients:? 1 = 1.69 W / (m * C) - coefficient of thermal conductivity of reinforced concrete; ? 2 = 0.18 W / (m * C); h1 = 0.5 m - base width; R = 3.28 m2* C / W.
Substitute the values into the formula: 3, 28 = 0, 5/1, 69 + h2 / 0, 18. From where h2 = 0, 537 m. Round off the value to 0.6 m.
Determine the volume of an insulator with a layer thickness of 0.6 m for thermal insulation of a structure 6x8 m with a height of 1. 4 m. Calculate the area of the trench around the building: ((6 + 1, 2)? 0.6 + 0.6? 8)? 2 = 18.24 m2.
The volume of the heat insulator for filling the pit is: 18, 24? 1, 4 = 25.5 m3… Round the value up.
Drainage system arrangement
Expanded clay is hygroscopic. If the groundwater near the house is at a depth of less than one meter, it is recommended to build a drainage system. Drainage is created regardless of which side of the foundation the material is poured into.
The work is done as follows:
- At a distance of 1.5-3 m from the house, along the perimeter, dig a trench, the depth of which exceeds the depth of the base by 0.5 m. Make the bottom with a slope of 2 cm by 1 m towards the water outlet.
- Lay geotextiles in the trench with an overlap on the walls.
- Place a layer of medium-sized crushed stone, 10 cm thick, and compact.
- Place a perforated pipe on the bottom, controlling the slope of the surface towards the drain.
- Equip the drainage system with wells to clear blockages and a collector to which water will be drained.
- Wrap the geotextile over the pipe.
- Fill the trench with soil.
Warming the foundation with expanded clay above the soil
An additional wall is built to insulate the basement. It is made of brick or concrete (pouring the formwork) at a distance of 20-30 cm from the house. The partition is erected with a sling up to the first floor. Pour the substance into the resulting cavity and cover it on top with cellophane wrap, backfill and brickwork.
Another option is to add granules to the concrete solution, mix thoroughly, and then pour into the formwork. This design retains heat poorly, because concrete conducts it well.
It is much better to prepare clay mortar with expanded clay. Stir the mixture until thick sour cream, and then pour into the gap between the partition and the plinth. Clay heats up slowly and gives off heat, therefore it is preferable to concrete.
Protection of the foundation with expanded clay from the basement side
Insulation of the foundation from the inside with expanded clay is used if it is impossible to use it outside. For work, stock up on boards treated with antiseptic agents.
Next, do the following:
- In the basement, build a wooden wall from the floor to the ceiling of the first floor and fasten it parallel to the base at a distance of 30 cm.
- Secure the structure with slopes.
- Place a waterproofing film on the floor of the fenced-off area.
- Fill the cavity from floor to ceiling with expanded clay.
External thermal insulation of the foundation with expanded clay
The process of warming the foundation with expanded clay from the outside is complicated by a large volume of earthworks, during which all the space near the wall is freed from the soil.
Operations are performed in the following sequence:
- Dig a trench along the perimeter of the foundation to its full depth. For the convenience of the master, the width of the pit should be within 0.8-1.0 m.
- Clean the surface of the base from dirt. Shoot down sharp corners and edges.
- Treat the wall with a special primer.
- After drying, coat it with bituminous mastic in a cold or hot way. In case of hot coating, preheat the agent to a temperature of 180 degrees over an open fire. The substance, which is intended for use in a cold state, simply mix and apply to the walls. For reliability, repeat the operation 2-3 times. Work with a roller with a long handle.
- Pour 15 cm of sand at the bottom of the trenches, level and compact it.
- Cover the pit with a thick plastic wrap overlapping the foundation along its entire height. It will protect the granules from groundwater. Wet grains lose some of their qualities.
- At a distance of 0.6 m from the wall, which coincides with the calculated thickness of the insulation layer, build a partition. It can be made from bricks, boards, slate, etc.
- Fill the space near the wall with expanded clay to the top, and with earth on the other side.
- Cover the "pie" with roofing felt with an overlap of 5 cm over the base and 15 cm over the adjacent sheets. Seal the joints with hot bitumen.
- Pour sand on top, and then soil.
- Pour a concrete blind area with thermal jumpers from bars around the perimeter of the house. The protective layer should be 10-15 cm thick with a reinforced mesh. Compounds for penetrating waterproofing can be added to the solution.
Internal insulation of the foundation with expanded clay
This method is used at the initial stage of building a house and is carried out over the entire area occupied by the house.
The work is performed in the following sequence:
- Align and compact the bottom in the pit.
- Place thick plastic wrap with an overlap on the walls and adjacent pieces. Glue the joints with reinforced tape. Roofing material can be used instead of a film.
- Spread a layer of granules on the floor.
- Cover it with cellophane for waterproofing.
- After construction, you can lay on the floor other means of a similar purpose, for example, mineral wool, and then fill the entire "cake" with a concrete screed.
Watch a video about expanded clay insulation:
Expanded clay does not belong to highly effective means. To achieve a good result, be sure to insulate the base in a comprehensive manner, not forgetting about waterproofing and moisture wicking. Deviation from the laying technology can lead to constant heat leakage through the foundation and even to its destruction.
