THE DEMANDING ART OF PRE-WATERPROOFING IN BASEMENTS
When working below ground in basements, its not unusual to face active water leaks. Sometimes the pressure is very high. It could originate either from a water tableor from perched water.
It needs the right workmanship and craftsmanship to bring off a task like pre-waterproofing.
- You need to accomplish an excellent preparatory work giving full attention to the minutest particulars.
- You need to work skillfully at a lightning speed with the appropriate very fast setting plugging mortars.
- You have to choose the right mortar, the mortar that will do the job.
Remember that however faint the water ingress might be, the waterproofing slurries we use to waterproof basements won't set properly and most probably they will be washed out.
Steps and actions to achieve a thorough pre-waterproofing
1. Locate all the ingress points that need pre-waterproofing.
2. Widen all linear points to a section of 2x2cm and all localized points (holes) to a parallelepiped of 3x3x2cm (2cm is depth). The sides should be sound and vertical (better if width is increased to the sense of depth).
Mortar should expand, anchor well and seal perfectly the voids. Surfaces should be ideally vacuum cleaned and completely saturated with clear water.
3. Mix not more than 0,5Kg of powder with fresh water (always add powder in water. Never the opposite!).
Mixing proportions : water / powder: 1 / 3,5 by volume.
Mixing should be effected in not more than 30 40. Don't forget that these interventions need full speed. You have to be fully concentrated and work very briskly.
4. Prepare a pear-shaped, stiff mass and when it starts getting warm in your hands, press it firmly on the hole and keep the pressure for about 60 without any movement of the hand(e.g. twisting motion).
5. For long cracks, you always should work from the weakest pressure to the highest.
6. Work patiently with big holes. Sealing is effected gradually with consecutive interventions.
7. Never use these powdery materials directly on the leaks(without premixing with water). Not only the waterproofing problem will remain unsolved, but furthermore any future intervention will be more difficult.
8. These materials should not be used in live (moving) cracks or for expansion joints.Their rigidity doesn't permit these applications.
9. Many times, particularly when high pressures exists, some auxiliary drainage measures are indispensible.I use rigid, copper pipes in combination with flexible pipes. I will give full details in a future entry.
Disclaimer: All information on this site is provided for informational purposes only! By no means is any
information presented herein intended to substitute for the advice provided to you by any health care or other professional
or organization.
