Damp basements cause headaches for many homeowners, because if left untreated, mold can form or damage the building fabric. Draining the basement yourself is a time-consuming process, but it can save a lot of money, especially in the long run. If the masonry or foundation is damaged by the moisture, high sums have to be paid for renovation; worse with a mold infestation.
What a shock! They were about to get something out of the cellar and noticed dark, damp spots and efflorescence in the masonry. It smells musty and the humidity is oppressive. This is where it gets tricky, because the longer you don’t address this issue, the worse it gets. A basement that is too damp does not simply dry out again and must be dehumidified accordingly so that it can be used again and no serious damage occurs. Mold growth typically follows, followed by possible structural damage, which is not an ideal condition. A big advantage: You can drain your basement yourself!
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The causes of damp basement walls, ceilings and floors are varied and can have to do with the age of the building, the building materials used or the location alone. This can help determine the cause of the dampness and take further action, such as using barrier concrete. The typical causes are:
- Moisture seeps through brick walls
- no horizontal barrier available
- poor ventilation causes accumulation of moisture in the basement
- Objects such as cupboards and carpets impede air circulation, which also leads to wall moisture
- Windows and doors are leaking
- leaking walls
- broken pipe
- Groundwater level rises over several years and more moisture is released into the basement
- defective drains
Many of these causes can be remedied with the instructions below, but if a pipe bursts or there is no horizontal barrier, for example, a professional must be hired to identify the problem and take care of it. This is especially important when construction work has to be done to dehumidify the basement rooms again.
Tip: be sure to check for possible moisture in your basement. Even if it’s just a few drops that seem to be seeping through the wall, ceiling, or floor, you need to drain the basement to keep the problem from spreading.
materials and tools
If you want to drain the basement yourself, you need the right tools. Since this form of drainage relies purely on dehumidification and not on the installation of an external seal or the distribution of barrier concrete (this can only be made possible by expert companies), it can be carried out by anyone. The following tools and materials are essential for the project:
- Dehumidifier or construction dryer
- vacuum cleaner
- door and window seals
- rubber grout
- safety goggles
- sealing mud
- insulation boards
- renovation plaster
- Mold remover if mold is present
- vinyl gloves
- Hygrometer (device for measuring humidity)
When choosing the mold remover, you can either use special mold cleaners or rubbing alcohol with a content of 70 to 80 percent. It’s also a good idea to wear a breathing mask if you have mold to avoid inhaling the toxic spores, especially if you’re treating the fungus after dehumidifying. This protects your health considerably and you can take effective action against the mould.
Tip: If you don’t have a dehumidifier, you can rent one at a hardware store, as these are available for around 40 euros per day or 120 euros per week. Be sure to pay attention to your electricity bill, as construction dryers use a lot of energy.
Before you can dry the basement, you must prepare it so that the moisture can be removed quickly. To do this, proceed as follows:
Step 1: First check whether doors, windows and other openings are tight and can be closed completely. Moisture can penetrate through these. It is also important to look for cracks and crevices in the walls.
Step 2: First replace the worn seals and treat the damage in the wall with rubber mortar. This is used like conventional mortar and does not even have to be touched.
Step 3: Then remove all objects from the basement. Discard anything soggy and anything that has mold on it. You could, for example, store large devices and furniture in the garden under a tarpaulin or in the garage. This is particularly important because this is the only way the air can circulate within the cellar and
once these preparations have been made, you can dry the cellar. Make absolutely sure that you have all the tools and utensils available.
drain the basement
When it comes to draining, the most important thing to remember is to be thorough and keep the equipment running consistently. Since a basement can store a lot of moisture in the walls, it is important that you follow the instructions carefully to complete this project effectively and as quickly as possible. Since you have the electrical devices on all the time, the costs are quite high. This means that the faster the basement was dehumidified, the more electricity you save. You can drain your basement with the following instructions:
1st step: It is important to air the cellar from time to time during the entire drying process. If you have a window or door in the basement that opens to the outside, be sure to air it early in the morning when it’s still cold. Warm air transports moisture better, so ventilation at high temperatures tends to have a negative effect on drying out. Also, refrain from ventilating during extremely cold winter days, as it may happen that the moisture in the wall does not evaporate.
Step 2: Now place the fan and dehumidifier in the basement and turn them on. Open all connecting doors and leave them open as wide as possible. The dehumidifier now takes the moisture out of the basement and the fan ensures effective air circulation so that the moisture cannot linger in the room. While using the dehumidifier, you have to keep checking it for the water tank. This fills up very quickly in a damp basement and must be emptied accordingly.
3rd step: You also have to put a radiator in the basement to heat it up again and again. The dry heating air removes moisture and ensures faster evaporation within the room, which of course benefits the walls. However, do not heat for too long when the dehumidifier is off as this could increase the humidity again.
4th step: Already during the drying process you take action against possible mold growth. Put on vinyl gloves, safety goggles, and a respirator. Now start treating and removing the mold with the alcohol or detergent. Especially when cleaning mold on the ceiling, be careful not to get anything in your eyes or mouth. After removing the mold, vacuum the basement and clean it with a slightly damp mop so that spores on the floor are removed even better.
Step 5: Now you have to wait until the basement reaches a maximum humidity of 60 percent and not more. By this time, the basement should be dry, which may take several days, depending on its size. Check the walls for moisture by hand. Finally, you can apply a layer of three millimeters of sealing mud to the walls with the brush and attach the insulation boards to these. Finally, plaster and then the basement can be used again.
Tip: After you’ve dehumidified the basement, consider taking on additional work to fix any other deficiencies. This includes repairing the drainage, bitumen sealing and possible retrofitting of the barrier concrete.
Costs for professional drainage
If you do not want to drain the basement yourself or if you have the necessary knowledge and building materials, for example if there is no horizontal barrier, it is worth hiring a specialist. In general, you should opt for a specialist company as soon as the wall moisture has progressed significantly and mold is already forming. Mold removal can be expensive. In general, the longer you wait, the higher the costs. The cost of drainage depends on the following points:
- the level of basement moisture
- the location of the areas to be treated
- equipment and materials used
- Need for subsequent renovation or refurbishment
- Appointment of a building surveyor
Before even contacting a draining contractor, you should first hire a building surveyor if a contractor doesn’t provide the service. Construction experts assess the damage and identify exactly how and where the moisture is getting in and what measures are required.
On average, the assignment costs around 250 euros , but the appraiser will tell you exactly what you have to do and save you a lot of money because you don’t have to commission unnecessary work. The general costs for drainage are not exactly cheap and are measured as follows:
- External waterproofing including excavation: EUR 350 – EUR 500 per m³
- Paraffin injection: 240 euros – 260 euros per m²
- Sealing of concrete joints: 50 euros – 70 euros per m
- Bitumen sheeting for basement ceilings: 5 euros – 10 euros per m
- Horizontal barrier: 80 euros to 150 euros per m; depending on the type of horizontal barrier
These are the various options for draining the basement and are heavily dependent on the damage pattern. For example, if you own a house that dates back to before 1960, the basement will probably need to be completely sealed. For example, if you need waterproofing for a basement that is 35 m², the costs are calculated as follows:
- Exterior waterproofing: around 15,000 euros
- Horizontal barrier: around 3,000 euros
- Drying via devices: around 700 euros
That would be 18,700 euros for this cellar. Of course, this is highly dependent and for this reason it is worth hiring an appraiser. You should also reckon with even higher costs in the event of mold infestation. Even a small area the size of a wardrobe costs between 600 euros and 1,000 euros and there is no upper limit here. For this purpose, building fabric and spare parts such as pipes often have to be replaced. Before choosing the company, be sure to compare possible competitors to find the best and most cost-effective provider that offers the right service.