A basement, together with the foundations, is the basis of a stable building. If the basement walls are not resistant to the pressure of the groundwater, this can lead to damp basement walls, fungi and other moisture problems that can damage the rest of the building. In addition, a basement is also a useful storage space where you can store a lot of items and food. It is therefore a shame if you are not able to make optimal use of this space. Basement sealing offers the right solution for this.
What is basement sealing?
In technical jargon, traditional basement sealing is also referred to as basement lining. This is to waterproof the basement walls so that they stay dry. Here you start from a watertight basement with a clean surface and damp walls.
Causes and effects of a damp basement
Moisture problems arise because the basement is not completely watertight, usually due to a combination of a high groundwater level with a low moisture resistance of the basement floor and walls. Sometimes this can have local causes, such as fine hairline cracks in the walls or the basement floor. In other cases, complete surfaces may be damaged and weakened due to a lack of maintenance.
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The basement can be affected by rain or incoming groundwater, but leaks can also cause enormous havoc, making the basement wetter and warmer. In addition, condensation can also occur, which means that your walls become increasingly humid and, in the long run, also offer the risk of other moisture problems such as mold.
When to choose basement sealing?
Basement waterproofing is a good idea if you want to make the basement really watertight and use it as a habitable space, for example. Sealing cellars is only effective in the case of a 'damp' basement and therefore not when there is a lot of water in the basement. Then basement drainage is more recommended.
A basement can be waterproofed on both the inside and outside. Waterproofing an existing home is more often used on the inside as the outside is often no longer accessible. Exterior basement sealing is only possible for new buildings. For an effective result, the entire basement (all walls and entire floor) is usually tackled.
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Benefits of basement waterproofing
By protecting your basement against moisture, the basement can again be used optimally as a storage room, play area, relaxation area, wine cellar... Additional benefits include a reduction in the energy bill, extra protection against underground water pressure and the fact that the stability of the home is no longer at risk.
Since basement sealing can come at a serious cost, the government offers a number of attractive premiums for those who have their basement sealed. You can use the various premiums website here. Basement sealing carried out by a moisture expert guarantees (decades) of years on a dry basement.
Perform basement sealing
Reynchemie has 3 methods for effective basement sealing: 1) the normal process for basement sealing, 2) if too much pressure is put on the walls and 3) if there is too high a concentration of salts.
Be sure to take enough time to identify and analyse all issues. If there are salts that migrate through the façade and form salt efflorescence, this problem must first be solved by means of a salt blocking agent: RC Sulfastop ZB whether RC Nitrablock.
1) Normal basement sealing
If you do not suffer from too high pressure (less than 1 bar), vibrations from a busy track or tram, cracking or too high a concentration of salts (less than 100 mg/liter of nitrates and 250 mg/liter of sulphates), we recommend that you carry out the basement sealing with waterproof cementation RC 221.
RC 221 is a water-repellent mortar for rough surfaces and is intended to ensure the watertightness of concrete and masonry inside and out. For example, for ponds, swimming pools, basement walls, retaining walls...
Basement sealing with waterproof cementation RC 221
1) Making the subsurface clean and structurally healthy with RC Decap 1 country RC Plug
2) Moisturize the surface
3) Apply a turnip coat of RC 221 mixed with RC Acryplast
4) Apply at least 2 coats of RC 221 crosswise with a trowel or sprayer
5) Smooth the mortar with a rule and rub up/talocate
In addition to a primer, RC Acryplast can also act as an improver of the mortar by adding it to the cement. For exact mixing ratios, consult the technical sheet.
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2) Too much pressure on the walls
If there is too much negative pressure (more than 1 bar) on the walls or there are too many vibrations due to a busy track/trambedding/etc., we recommend working with a flexible sealing mortar RC MULTIFLEX 2M. The product will ensure that the walls become resistant to high water pressure again (up to 8 bar).
Basement sealing with flexible sealing mortar RC MULTIFLEX 2M
Follow the same procedure as the watertight cementing technique, but use RC MULTIFLEX 2M instead of RC 221 elastic sealing mortar. It is also possible to work with an RC 221 underlay on which RC MULTIFLEX 2M is placed.
3) Too much salt in the walls
If there is too high a concentration of salts in the walls (more than 100 mg/liter of nitrates and 250 mg/liter of sulphates), we recommend treating the walls with a sanitizing and salt buffering mortar, more specifically RC Sanisel. This lightweight water-repellent mortar ensures that salts no longer have the chance to migrate through the wall and cause damage to the underground space.
Basement sealing with a salt buffering mortar
First waterproof the walls with RC 221, 222 Lankofugeant or RC MULTIFLEX 2M depending on the circumstances. Then apply RC Sanisel to a minimum thickness of 0.5 cm. The final thickness of this salt buffering mortar should be 2 cm. To smooth the walls afterwards, use a vapor-open plaster such as RC Calcoliss 300 whether RC Intralime F.
click herefor the full specification with RC Sanisel.
Reynchemie's expertise and range
Basement sealing is not an easy job. There are many things to take into account: choosing the right products and materials, respecting the correct drying time, applying the correct techniques... Also, keep in mind that every situation is different and requires a specific approach. In fact, basement sealing may not be the best solution for the moisture problem in your basement at all. Carrying out self-sealing of the basement is therefore not recommended.
Are you sure of a correct diagnosis and approach? Be sure to contact one of our technical advisors via our contact page. We would be happy to bring you into contact with a certified company to seal your basement.
