Most houses are based on an extremely useful space: the basement. However, in the case of an old house, the fitting of the basement in the bedroom or in the playroom is not always possible, due to moisture or waterproofing defects. Before thinking about rearranging your basement, first, make sure it does not present a water inlet problem.
Evaluate the land in your home. Make sure the ground slope is not oriented toward your foundations, as garbage tends to gather on the rest of the ground rather than near the foundations, thus creating a slope directed towards your home. If necessary, backfill your ground to have a 10% slope directed towards the opposite side of your foundations. This slope corresponds to a difference of 1 cm every 10 cm. Ensure that the top of the backfill is at least 15 cm below the base plate so that building materials are not in contact with the ground and run the risk of rotting in the ground 'to come up.
Identify problems that may arise near your foundations. Keep your gutters clean and make sure that the gutter downspouts are located at least 1.50 m from your foundations.
Watch for shrubs and other plants that are very close to your foundations. Decomposed roots, can create a path allowing the infiltration of water into your foundations. You should avoid having plants within 30 cm of the foundations. Be sure to keep a slight slope to drain water out.
Consider waterproofing your walls with a product such as Drylok or Xypex in case of minimal and intermittent water intakes.Drylok is a waterproofing product and not a sealant. It expands as it dries and adheres to the wall. Xypex is rather an impermeable coating that sticks to the surface on which it is applied. It uses moisture to create an impermeable crystal structure. Therefore, if a surface covered with Xypex has small leaks of water, these leaks will disappear by themselves, as they will be absorbed by the product. However, Xypex costs 2 to 4 times more expensive than the Drylok. Be aware that with such solutions, groundwater under your foundations or under your walls is under significant pressure.
Repair cracks and other defects in the concrete walls and treat the passages of the assembly rods and pipes. If you spot a crack that extends the full width of a wall, immediately think of a potential water inlet. In masonry, cracks that are not subjected to thermal or mechanical stress can be effectively treated with Drylock Fast Plug. Another way to repair cracks in a wall is to fill them with epoxy for masonry. There are epoxy and polyurethane repair kits that you can implement yourself, but they are not very reliable. In general, it is better to call on a specialized technician to do this kind of intervention.
Consider installing a sump. This is a hole in the basement, which is equipped with a pump. When the water level in the sump exceeds a certain level, the pump starts and drains the water out of the house, 3 m or more from the foundations. The installation of a sump requires some experience because you will have to dig a hole in concrete, install it, install a coating, connect the pump and install the drain pipe to the outside.
Install a foundation drain (French drain) if water problems are severe. A French drain includes underground pipes that are placed around the basement. The installation of a French drain is similar to that of a sump, but it also requires digging a trench approximately 30 cm wide in the basement, in which you will place the drainage pipe. The trench will then be filled with gravel before being covered with concrete. A French drain is always provided with a sump and a pump to evacuate the water to be collected in the drainage system.
Ask a specialist to inject clay around your foundations. It is a waterproofing product derived from betonies, which is a colloidal clay having the property of absorbing very large quantities of water. Generally pumped from the outside, the clay fills the voids and follows the paths of water flow to your foundations, clogging the cracks in the basement permanently. This product is used for waterproofing tunnels, manholes, dumps, ponds, elevator shafts, etc.
Before rearranging your basement, monitor the area during heavy rains. If you do not see water in a year, it is very likely that you will not have any problems in the future, as long as you keep your gutters clean and you take care of your foundations!
When installing a sump, be sure to apply local plumbing regulations. On most installations, you will need to set up a check valve to prevent water from returning to the sump through the drain line.
Be aware that it is better to permanently solve the waterproofing problems of a house during construction. The good old method of protection with a plastic film and a Styrofoam panel is still working quite well, but it is not resistant to backfilling of foundations, which results in leakage. This method is no longer in compliance with international building standards and building codes of many cities, regions, and countries. Drylock manufacturers suggest coating the outside of the foundations with Drylock Masonry Waterproofer. Remember that the effectiveness of a basement waterproofing product depends on the condition of the surface to which it is applied.
Mold poses a serious health risk. Consider using a dehumidifier to have a dry basement.
If the waterproof paint is ineffective, you must decrease the hydrostatic pressure by allowing the water inlets. You can then use an apparent drainage system without having to cut the basement floor.
When cutting concrete, always wear goggles and a mask or respirator.