Under the conservation of the foundation is understood as a set of measures to protect building structures from adverse environmental influences in the cold season. The need for protection arises in the event of a forced stoppage of construction due to the impossibility of its completion before the start of frost.
The main factors contributing to the destruction of the foundation in winter are:
- moisture exposure;
- low air temperature and its sharp changes;
- deformation pressure from soil heaving.
The list of protective measures and work performed depends on the type of foundation, its dimensions, lower support point, freezing depth, type and composition of soils.
What determines the need for protection
If concrete and stone structures are not mothballed, an existing foundation is very likely to receive obvious and hidden mechanical damage during the winter. Obvious defects include visible discontinuities, cracks, deformations, delaminations, subsidence and elevations of individual elements.
Hidden damage inside the concrete monolith, which can manifest itself only when the building is already built, is even more dangerous. As a result, this will lead to financial losses due to the inability to operate the facility.
When can a conservation be abandoned
The greatest risk of damage during the cold season is for strip and slab foundations. Pile structures are most stable, especially if there is no grillage yet. In addition, the need to use foundation conservation technology for the winter depends on the degree of readiness of the foundation.
And yet there are cases when protection can be waived:
- monolithic elements were made a month before the onset of cold weather, concrete had already managed to gain full strength;
- vertical and horizontal waterproofing is made efficiently and in full;
- backfilling of the sinuses was done with careful tamping (material on this topic is here);
- on the site of the future blind area around the perimeter of the building, a clay hydraulic lock is arranged.
If all these conditions are met, the foundation will not be needed. The issue of the quality of waterproofing and the depth of groundwater are paramount here.
Ways to protect foundation structures
Proper conservation of the foundation before winter will not only preserve integrity, but will allow concrete to gain ultimate strength over these months. As a result, it will be possible to begin the construction of walls with the onset of the thaw and, due to this, complete the construction faster.
How to preserve the foundation for the winter? In order to ensure reliable quality protection of the foundation, the list of work performed should include:
- building perimeter insulation;
- the presence of vertical and horizontal hydraulic isolation;
- replacement of heaving soils with compacted dry sand;
- hydraulic lock device along the entire perimeter of the building.
With a high level of groundwater, drainage pipes should be laid and effective water drainage should be ensured.
Recommendations for the conservation of foundations of various types
The choice of the method of preservation of the foundation foundation for the winter largely depends on the type of construction. It is important to observe the sequence of stages of the work. So, even small violations in the waterproofing device can lead to the penetration of moisture and the destruction of critical structural elements.
Strip foundations
How to preserve the strip foundation for the winter? Foundation foundations of the tape type are most at risk of destruction in the winter season due to adverse effects. This is due to the large contact area of the structure along the vertical wall, which increases the pressure from the expanded soils and the effects of moisture accumulating in the soil after autumn rains.
Therefore, the conservation of the strip foundation for the winter should provide for the maximum level of protection of building structures. Work performed should include:
- complete removal of the formwork, as the wood will contribute to the accumulation of moisture, followed by its transfer to the concrete monolith;
- hydraulic isolation of all structural elements (roll, coating and impregnating materials are used);
- warming of the side walls with foam or other moisture-proof insulation;
- sheltering the structure with reinforced plastic film;
- installation of a drainage system at a groundwater level of less than 500 mm to the bottom of the foundation or freezing of the soil.
Concrete work must be stopped at least one month before the onset of frost. During this time, concrete will have time to gain the necessary strength for successful resistance to negative external influences.
Slab-type foundations
The large area and small thickness of the plate lying on the ground contributes to the greatest mechanical impact when the soil swells. And although the presence of a sand and gravel pillow, according to SNiP, reduces this effect, damage can still occur.
In addition, there is a high probability that even if the monolithic slab remains without damage, then the insulation laid below will be crushed and will not be able to provide a normal decrease in heat losses of the building in the future.
Therefore, all concrete work on the construction of the slab foundation must be completed 30-40 days before the onset of cold weather. After a month, you can begin to preserve the slab foundation for the winter.
All side surfaces of the foundation should be covered with waterproofing materials (for more details, see here), and the surface of the plate should be coated with reinforced plastic film in 2 layers or filled with bitumen. However, the last recommendation will entail the need for a cement screed during the further construction of the building.
If there is an opportunity to go for additional expenses, then a good effect can be achieved if the surface is filled with expanded clay or coal slag with a layer of 100 mm. Subsequently, these materials can be used to insulate attic floors or blind areas around the house.
Column and pile foundations
The foundations of these types are the least susceptible to negative environmental influences. This is due to the small area of direct contact of the structure with soil and air. It may be necessary to protect the grillage if it is made in the form of reinforced concrete monolithic beams.
In this case, they must be treated with a bitumen primer and wrapped tightly with a reinforced plastic film. At this, the conservation of the columnar or pile foundation can be considered completed.
Features of conservation of foundations for a long period
If you understand that the construction of the building will be suspended for more than a year, then with the onset of faithful you will have to partially decommission the foundation and perform additional work. For this:
- remove plastic film from all surfaces so that the concrete and masonry dry well during the summer;
- extend and make drainage lines according to the scheme of constant work;
- Take care of the permanent blind area around the entire building;
- install a shallow tap at least 10 meters high, mount the descent from it and the ground loop;
- provide reliable waterproofing of all vertical and horizontal surfaces.
In order to reduce the lateral pressure of the soil during heaving and to preserve the thermal insulation properties of the material, use insulation for walls with a thickness of at least 100 mm. All of these activities will save the foundation. for up to 5 years without continuing construction.