Unfortunately, there are cases when the house has already been built and occupied, and here it turns out that the waterproofing of the foundation has either not been carried out, or it has not been done well. This is indicated by constantly wet walls in the basement, and even puddles that form at their base. Wall decoration quickly becomes unusable, and the half-measures taken do not bring results. This is one of the options when you need not only to think about the current situation, but also to carry out the necessary moisture protection measures. Do it yourself, or hire a repair and construction team, everyone decides for himself. Further in the article, situations will be considered when it is desirable or necessary to waterproof the foundation, and what activities can be done with your own hands.
When does the need to waterproof an existing foundation arise?
One of the cases has been discussed above. Why could this happen? There may be several answers.
- During construction, waterproofing was not done, since at that moment the soil was dry, no groundwater was observed. As time passed, the situation changed, the result was not long in coming.
- The waterproofing of the base of the built house was carried out, but not with the material that meets the existing conditions (for example, with high soil moisture, they decided to get by with bituminous mastic or waterproof plaster).
- Vertical waterproofing was carried out with high quality, but the drainage system was not taken care of, and the area is swampy. Under such conditions, without moisture removal, not a single created hydrobarrier will be effective for a long time.
In what other cases may insufficient waterproofing work be manifested in a completed building?
Suppose there is a small, by today's standards, house on an unburied foundation, which is made on the basis of stone or blocks, that is, it is not monolithic. If you do not take care of the removal of water of atmospheric origin from the base of the house, with heavy rainfall, the soil on which the foundation sole rests will get wet and become pliable. Since the foundation is not monolithic, some sections sag, which is manifested by cracks appearing on the surface of the walls.
Let's consider another option. The house is old, and for some time now the walls have begun to fill with dampness from the inside near the floor. Outside, if the wall is not under the cladding, it is also noticeable that the surface is wet closer to the plinth and moss or mold is already starting to grow in some places. What can you think about? That's right, over time, the waterproofing between the base (base) and the wall fell into disrepair. Something needs to be done, because during the period of heavy rainfall or snowmelt, the wall is very wet, causing the finish to deteriorate and fungus to start.
Waterproofing of a buried foundation in a constructed building
It should be noted right away that the upcoming work is very large-scale, so you can’t hope to complete the entire volume with your own hands. The plan of action in the presence of such a problem is as follows:
- sampling of soil along the perimeter of the building in order to provide access to the foundation surface;
- cleaning the base of the house from adhering soil and assessing its condition, possible causes of getting wet and making a decision about the upcoming set of waterproofing measures;
- carrying out the necessary work and filling the soil;
- installation of a blind area around the perimeter of the building.
The complex of waterproofing measures depends on the problems discovered during the “opening”. If there is no hydro-barrier coating on the surface at all, it must be done. Which material to choose in this case depends again on the conditions found. If the soil moisture is moderate, and the water from below is not suitable, you can get by with a relatively inexpensive, in every sense, rolled hydroprotection of the surface. If the fact of approaching groundwater is detected, additional care must be taken to equip a full-fledged drainage system.
In the case when the waterproofing material is applied to the foundation surface, however, it passes moisture, it is worth using the installation of an additional, more reliable hydro-barrier (film membrane, for example). There is no point in applying another layer of the same product that was used originally. If one layer has not coped with the task, there is no guarantee that the second one will be more effective in given conditions.
Important! If a situation has arisen when waterproofing for some reason does not fulfill the functions assigned to it, it is necessary to accurately determine the cause of this phenomenon. There can be many factors, from the use of low-quality material to hidden hydrological features of the building site. Only a competent specialist of the corresponding profile can understand this. It is not advisable to draw conclusions on your own, and make decisions in this case.
Protection of an unburied foundation from excessive atmospheric moisture
The situation described above happens quite often with both old houses and new buildings. In both cases, if we exclude the incorrect calculation of the width of the sole of the base, this occurs due to the accumulation of excess atmospheric moisture in low places near the foundation. That is, there is a deepening of the soil relief, where, after rains or melting snow, extensive puddles constantly form. There is a deep oversaturation of the soil with moisture, which is why a reliable support disappears under the foundation in this place.
How, in this case, to remove moisture from the base of the house? There are two ways to fix the situation, or rather a combination of them:
- diversion of water to another place (outside the site or to a specially created underground reservoir) by creating surface drainage;
- arrangement of a wide solid blind area.
Do-it-yourself drainage can be made from any durable pipe made with weather-resistant material, directing it from the problem area to the slope. It is possible that for this it will need to be buried in the ground. Another option would be to build a concrete gutter that would serve the same function.
Even if drainage is done, it is worth taking care of creating a blind area that will prevent atmospheric precipitation from saturating the soil near the building itself. Moreover, the arrangement of such a structure does not have any special technological difficulties, therefore it is quite possible to make it with your own hands.
We make a blind area with our own hands
To make high-quality concrete protection of the foundation structure from excessive surface moisture, you will need the following materials and a set of tools:
- components for the preparation of concrete (crushed stone of a medium-sized fraction, sand, portland cement);
- gravel (large gravel);
- board for the manufacture of formwork;
- metal or polymer coarse mesh for reinforcement;
- concrete mixer;
- rule;
- Master OK;
- plaster float;
- earthwork tools.
The work steps are performed in this order.
- Dig a trench and select soil around the perimeter of the building (width about 80 cm, depth about 20-25 cm).
- Fill the bottom of the trench with large gravel with a layer of 10-15 cm, pour sand on top so that its top is slightly below the soil level.
- Moisten the bedding with plenty of water and mount the vertical formwork. Lay the mesh for reinforcement.
- Prepare concrete in a ratio of 4:2:1, where, respectively, fine gravel (screenings), sand and cement M-400. The consistency of the solution is semi-liquid.
- Pour concrete between the house and the formwork and level it in two perpendicular directions.
- When the concrete sets a little, grind the surface with a plaster trowel.
Important. If the blind area is done in the summer season, you need to protect the concrete from quick drying. To do this, the concrete structure (after the mortar has set) must be covered with a dark plastic wrap or some kind of dense cloth. When covered with a cloth, it is advisable to moisten it daily. Under these conditions, concrete will gain maximum strength, which will greatly increase the durability of the blind area.
We solve problems with waterproofing a long-built house
Previously, the choice of materials for creating hydrobarriers in construction was not so great. To be more precise, there was no choice at all. There was only, that is, cardboard impregnated with oil products. So it was used to create a hydrophobic gasket between the wall and the plinth. The service life of roofing paper is not that great, even in conditions where it is tightly sandwiched between two surfaces. That is why in buildings that were built 50 or more years ago, bridges appear where waterproofing has ceased to be it, through which moisture from the basement passes to the bottom of the wall.
What can be done in such a situation? Raising the building to lay a fresh waterproofing layer is unlikely to succeed. There is only one way out - to protect the foundation together with the base from moisture from the outside, from where it comes up in most cases. It is problematic to isolate the sole of the base, firstly, and secondly, there is not much point, since groundwater rarely reaches such a level (we are talking about a shallow base), the problem here is excess moisture of atmospheric origin.
Now about how to get out of this situation. The foundations that were made a long time ago were in most cases poured on the basis of natural stone, so the outer surface is unlikely to be even and uniform. Therefore, it is better to use not those materials that are intended specifically for moisture protection, but somewhat different ones. It is best to use hydrophobic derivatives of polystyrene (foam or extruded polystyrene foam). If you prefer polystyrene (it is cheaper), you need to purchase it with a density of at least 35 kg / m2.
Protecting the base of the house from moisture with polystyrene foam
In addition to the mentioned sheet polymer (thickness can be used in the range of 30-50 mm), the following materials are useful:
- special mounting foam for gluing polymer plates;
- dowels with a mushroom cap.
The tools are needed.
