The reliability of the sauna stove depends on the foundation. The article provides examples of making foundations, depending on the material of the furnace and the properties of the soil. Content:
- Types of foundations
- Base for a lightweight oven
- Shallow foundation
- Slab base
- Pile foundation
- Use of rubble concrete
- Recessed base
The durability of the furnace depends on the correct manufacture of the foundation. The base of the heating module is built according to long-established building codes, and non-compliance with repeatedly proven construction technologies leads to a distortion of the furnace and the formation of cracks in the walls of the structure.
Choosing the type of foundation for a bath stove
The type of foundation for the stove in the bath depends on the weight of the building and the properties of the soil, so study the following information:
- For purchased metal ovens that weigh within 250 kg, a solid base or shallow foundation is sufficient.
- Brick kilns are more massive, weigh at least 700 kg, and a reinforced concrete foundation is required. The weight of a brick kiln can be determined based on the approximate mass of a square meter of masonry - 1350 kg (about 200 bricks plus mortar).
- For furnaces weighing over 2000 kg, a reliable reinforced concrete foundation with a depth of 1.5 m is built.
- The height of the furnace foundation is made in three ways: to the floor level, at the level or slightly higher. The foundation is made below floor level so that air enters the furnace from below, from under the floor. Advantages: the floors warm up faster and the combustion air does not come from the steam room.
- On suspended soils for brick ovens of medium size, a pit is prepared with a depth of 60-70 cm.
- If there is loam or clay on the site, find out the depth of freezing of the ground for your area. Dig a pit below the freezing point. If there is no data, go deeper one and a half meters.
- Make sure the groundwater is far from the surface. The foundation is kept to a minimum if the water is close, but the area of the structure is increased to ensure stability.
- If the soil contains sulfates, use sulfate-resistant cement of the SSPTs brand in construction.
- It is advisable to make the foundation of the stove and bath at the same time. In this case, the pits are made of the same depth.
- The size of the foundation for the stove in the bath must exceed the size of the stove by 100-150 mm in the horizontal plane.
- Formwork is necessary if the edges of the foundation pit are loose and crumbling.
Foundations for iron and light sauna stoves
Despite the small weight of metal products, the foundation for the iron stove should not be associated with the foundation of the room. When marking the pit, plan so that after construction there is a guaranteed gap of 5 mm between the foundations of the stove and the bath.
The foundation for a metal furnace is made as follows:
- Mark the pit on the surface of the earth. The horizontal dimensions of the pit must exceed the dimensions of the lower base of the oven by at least 10 cm.
- If you want to subsequently sheathe the slab with a brick, count the indent from the front side of the intended wall.
- Dig a pit 50-60 cm inside the markings if the soil is not powdery. For heaving, increase the depth - up to 1 m.
- Pour rubble into the pit and tamp it. Backfill thickness - 30 cm.
- Prepare a cement-sand mortar in a 1: 4 ratio. Use cement grade M200. The solution should flow freely.
- Pour the crushed stone with the solution and leave to dry for 2 to 3 days.
- Waterproof the cement pad with roofing felt and hot bitumen.
- Make a formwork from thick planks according to the design dimensions and install it in the pit.
- Prepare concrete in proportions: 1 part cement, 2, 5 parts sand and 4 parts fine gravel. It is allowed to replace gravel with expanded clay, which has thermal insulating properties.
- Pour the concrete into the pit and level the surface to the horizon.
- The foundation should dry for about a month. To prevent cracking, often moisten it with water - just sprinkle it generously.
- Instead of concrete, brick is often laid on top of a cement pad.
- The concrete foundation has an ugly appearance. For refinement, it is often lined with bricks or thick ceramic tiles. The latter option is preferable due to the low weight of the tile.
Making a shallow foundation for a stove in a bath
The most popular type of foundation, as most brick ovens weigh 1000-1250 kg. It is used if the groundwater is deep underground.
To make a high-quality foundation for a stove in a bath with your own hands, do the work in this order:
- Dig a hole 70 cm deep, its dimensions should exceed the dimensions of the base of the stove by 20 cm. Measure the distance between the foundations of the stove and the bath, the allowable size is 50 mm or more.
- Expand the lower part of the pit by 10 cm in all directions. The "heel" will allow the foundation to resist ground movement.
- Cover the bottom with sand (15 cm layer). Tamp it down, sprinkle it with water, make sure the water is completely gone.
- Pour broken brick, stone, crushed stone into the pit in a layer 20 cm thick, and compact.
- Pour sand again, level with a shovel and pour water over. Repeat the operation until all voids are filled with sand.
- Pour rubble into the pit, level and tamp. The final thickness of the crushed stone is 10 cm.
- Build a formwork around the perimeter of the pit. Provide a gap of 10 cm between the wooden wall and the edges of the pit, as much as possible.
- Make a reinforcing frame from an 8 mm rod and install it in the pit.
- Fill the hole with concrete, level the surface in a horizontal plane.
- Cover the foundation with foil for better hardening (2-3 weeks).
- Moisten the foundation in the same way as above.
- Remove the formwork after a month. Cover the side walls and tops with several layers of waterproofing.
- Fill the remaining cracks next to the foundation with sand.
Slab foundation on a columnar support for a sauna stove
It is used on highly heaving and clayey soils or in the case of a fair depth of soil freezing. You can also build on dry soils to save building materials.
Stick to the following working order:
- Remove the soil inside the markings by 150 mm.
- Drill cylindrical holes with a diameter of 20 cm (4 pcs.) In the corners, the depth of which is 30-50 cm below the freezing level. The wells should not go beyond the markings.
- Pour crushed stone into the wells with a layer of 10 cm and tamp.
- Install the roofing material rolled into a cylinder into the holes, which will serve as formwork and waterproofing of the pillars.
- Make a frame for wells and a foundation pit from a bar, install them in their regular places. Reinforcement or wire with a diameter of 8 mm is suitable for the frame.
- Prepare a concrete solution (see proportions above) and fill the foundation pit. First, fill the wells with concrete and tamp it with a vibrator, then the foundation pit. Fill everything without interruption so that the pillars and slab form a monolith.
- After the concrete has hardened, after about a month, waterproof the foundation in any way. For a strong concrete, dampen it daily.
Pile foundation for a stove in a bath
A simplified version of the previous foundation. Withstands the heaviest ovens. Consists of piles of various designs and a 15 cm thick reinforced concrete slab.
A simple but expensive option involves the use of purchased metal piles. Thanks to the special blades, they are screwed into the soil, at the same time compacting it. Screw in the products 30-50 cm below the level of soil freezing. Install a monolithic reinforced concrete slab on top of the piles, leaving a few millimeters of gap between the base of the slab and the ground for shrinkage. Secure the slab to the piles. Waterproof the surface with roofing material in two layers and hot bitumen impregnation.
Instead of metal piles, concrete piles can be made, as in the case of a slab foundation on a concrete support. The stove should be larger than the oven. A welded metal frame may be used instead.
Foundations from rubble concrete for a sauna stove
It is used in the presence of a large amount of construction waste from stone, brick, crushed stone, popular due to the low cost of building materials. Suitable for stoves up to 2 tons, but can be used instead of buried foundations.
Manufactured as follows:
- Dig a pit 1-1.2 m deep for heavy furnaces or 0.6-0.8 m for furnaces up to 2 tons. The horizontal dimensions should exceed the furnace dimensions by 20 cm.
- Tamp the soil at the bottom of the pit, add 15 cm of rubble to the bottom and compact again.
- Make the formwork according to the dimensions of the foundation and lower it into the pit. Waterproof the formwork from the inside.
- Lay large stones up to 15 cm in size on the bottom of the pit with a layer of 30 cm. Pour rubble into the pit and fill the voids between the stones.
- Prepare a cement-sand mortar at the rate of 1: 3, dilute with water to the consistency of liquid sour cream and fill the stones in the pit. Make sure there are no voids between the stones.
- If after the first installation half of the pit is filled, repeat the operation with stone, gravel and mortar and finish the work in one day. If the pit is deep, continue the next day. The last layer of stones is laid at a distance of 7 cm to the floor level.
- Make the upper plane horizontal with cement mortar.
- How to care for concrete during curing is spelled out above.
- After the foundation has hardened, waterproof all surfaces.
Recessed foundation for a stove in a bath
To decide how to make a foundation for a stove in a bath in your area, find out the composition of the soil. A buried foundation is built on clay or loess soil and for furnaces weighing more than 2000 kg. The reason is in the properties of the soil: porous clay expands in frost, and loess soil turns into liquid mud in rain.
The foundation for heavy furnaces differs from a shallow foundation in the depth of the pit and fittings. For dry soil, the pit should be deeper than 80 cm. Often, in order not to find out the type of soil, the pit is dug 1.5 m deep. The distance between the foundations of the furnace and the bath is at least 50 cm. The sequence of work is the same as in the manufacture of a shallow foundation … For the manufacture of reinforcing mesh, use a rod with a diameter of 12 mm.
For review, we suggest watching a video about arranging the foundation for the stove:
A well-made foundation guarantees the durability of the stove. Therefore, coordinate the choice of the type of base with an experienced stove-maker, who will also advise on how to fill the base for the stove in the bath. Neglect of building technology can lead to a tilt of the chimney and breakage of the roof.
