From time immemorial, in the Russian hut, stoves were installed on the floor, for this purpose the floor beams were strengthened or an extra was laid. Today, a furnace that does not have a foundation is a rarity; builders cut floor beams into the first crown to save money, while the previous installation method can no longer be called suitable. In addition, the foundation for the furnace is necessary to increase the stability of the structure and eliminate destruction. Traditionally, the foundation is made of cement-based buta or concrete, which is poured in such a way that the foundation 10 cm extends around the perimeter outside the furnace.
The height of the base should be the same as the height of the foundation of the main building. On top of the finished structure, roofing material or roofing material is laid in two layers, on which bricks and outlets from metal corners are laid in order to build fire-resistant cuts. But if you decide to install the foundation for the furnace, then you must follow some rules. For example, it is not possible to additionally concrete previously laid substrates, since there will be uneven shrinkage of the furnace. Therefore, the foundation for it is not associated with the foundation of the house. But if both of them are located as close as possible, then between them it is recommended to put a backfill from crushed stone, the thickness of which will be equal to 0.5 m.
The need for a foundation for the furnace and the determination of dimensions
Some owners of suburban and private houses are interested in whether a foundation is needed for an oven. To solve this issue, it is necessary to determine the dimensions of the future design. The weight of the furnace also determines the need to equip the base. A newly laid structure will weigh about 8 tons; after the solution has dried, the mass will be reduced by half. Sometimes a separate foundation is also formed for the root chimney, this eliminates uneven shrinkage.
The depth of the location of the base will depend on the strength of the soil, the heaving of the soil, the depth of freezing, the laying of the foundation of the main building, the level of groundwater location, as well as the question of whether the construction of the main building was completed at the time of construction of the foundation for the furnace. On dry sandy soils, the foundation for the furnace must be laid at 80 cm. If we are talking about heaving soils, then the depth should be below the freezing line by 1.5 m or less. In order to determine whether a foundation is needed for a furnace, its future mass should be calculated using a formula that looks like this:
- P = 1350 x V,
where V is the volume of masonry in meters;
1350 - approximate weight of 1 m 2 masonry in kg (mortar + about 200 bricks).
Building a foundation for a metal furnace
If you decide to build a foundation for an iron furnace, then you should not think about the need for a foundation, even if you use thin ultralight steel in your work. If the future design will weigh about 150 kg or less, then first you need to prepare a foundation pit and fill it with crushed stone. The layer is well compacted, in the end its thickness should be equal to 30 cm. A solution of cement of medium yield should be poured from above and left for a day to solidify.
The ratio of ingredients should be as follows: one part of cement, four parts of sand and liquid “by eye”. From this solution, pour the sole of the foundation. Pieces of roofing material are laid on the dried layer to exclude the effects of water, and after the pit is filled with a mixture prepared in the following proportion: one part cement, fine gravel in the amount of four parts, 2.5 parts sand and water. Using the level, the master must check the horizontalness of the base.
Specialist advice
If you decide to build a foundation for the stove in a wooden house, then you can replace concrete with brick. But the first option will be stronger and cheaper, however, if there is gravel and sand nearby. If necessary, the concrete foundation will be difficult to dismantle, but masonry made of brick lends itself to such work much easier.
Foundation for a brick oven
If you decide to lay the foundation for a brick oven, then you should prepare a foundation pit, having gone deep below the freezing line of the soil. Its dimensions should be larger than the future foundation by 10 m around the perimeter. This will prevent the influence of soil movements. 15 cm of sand are poured to the depth of the pit, which is filled with water. As soon as the liquid leaves, the sand must be added to the desired level, and then again filled with water. After the battle of bricks or a 20 cm layer of stone is laid to the bottom. Tamp the preparation and cover it with sand, and then fill it with water. This procedure must be repeated several times until the sand ceases to settle.
Before making the foundation for the furnace, after all the above-mentioned manipulations, it is necessary to pour a 10 cm layer of crushed stone, compact it, and formwork inside the foundation pit so that 10 cm of free space remains between the boards and the sides of the foundation. There must be a reinforcing cage inside the formwork.
Wizard Recommendations
In order to choose the kind of foundation, you should know the approximate mass of the future design. For this, the weight of the bricks to be used for construction is calculated. As a rule, stove-furnaces have a weight of more than 1200 kg, so they provide for the presence of a fairly massive foundation.
Methodology for the construction of the foundation for a brick furnace
Speaking of the above, it can be noted that concrete should be poured into the formwork. Once the solution has dried, the boards can be removed by applying several layers of tar to the sides of the foundation. The formed free space should be covered with coarse sand or fine gravel.
Building a wooden foundation
Experts do not recommend building a wooden foundation for the furnace, but if you are interested in familiarizing yourself with the technology of its construction, you should read the information below.
At the first stage, wooden poles are prepared and processed , which provides for their antiseptic or firing. This will extend the period of their use, as soil moisture will affect the surface of the products. Next, the site is marked and cleaned, holes are excavated, the diameter of which is 1.5 times the diameter of the prepared supports, and after that a sand cushion is arranged.
This base does not do without waterproofing, after laying the layer of which pillars are installed. To increase the bearing supporting area, such poles should be placed on a concrete slab or cross. The next step will be backfilling, leveling the supports in the horizontal plane and waterproofing the ends of the posts.
It is quite simple to build such a foundation under the oven with your own hands, however, labor and time costs will be more impressive. This is also due to the fact that the wooden foundation will have to be additionally protected from moisture, as well as the increased influence of temperatures from the furnace.
Reinforced concrete slab on supports
The furnace can also be installed on a reinforced concrete slab, the thickness of which varies from 15 to 20 cm. This design is laid on columnar or pile supports, which will depend on the depth of freezing of the soil. If the territory has clay soil with surface groundwater, it is best to give preference to the slab foundation. Such a foundation should be equipped separately from the main foundation, and the gap between these structures should be approximately 5 cm.
Conclusion
If you prefer a columnar structure for a furnace foundation, then for its construction you will need four posts in the amount of columns, on which a reinforced concrete slab or a frame of steel profiles will be installed. Supports should be located at the edges. Pillars will help to avoid seasonal soil movements that occur as a result of heaving of loamy and clay soils during severe frosts.