In the underground parking area of our complex there is some strange white residue that appears like some sort of product of a water pipe leak.
Overnight the residue falls down on my neighbours car.
Is this something that requires a professional to address and/or fix? Or is this something that just needs regular scraping which I can do myself?
Oh, that's bad. That's the strength leaching out of your concrete by water moving through the slab.
How that exactly happens is in this video here... but those substances are keeping your concrete aklaline, which keeps the reinforcing mesh from rusting.
Concrete is slightly porous. You have a problem above this concrete where water is not being swiftly drained. The water is sitting, and it's seeping into the concrete, and it's taking out minerals as it travels through the concrete. It is then depositing some of those minerals there.
As the minerals are leached out of the concrete, the pH lowers, and the reinforcing rod starts to rust. Rust expands, so this creates spallation and separation, destroying concrete's ability to be strong in compression.
At Champlain Towers, this caused the pool deck to rot where there was no building above it to keep dry. It punched through the columns. If people had left the moment that happened, they would have made it out. There's a lesson! The now-sagging pool deck (which continued as the first floor of the building) was pulling sideways on the building's columns.
So fix your drainage and do it fast.
Get a structural engineer out to tell you how bad it is. They can core the concrete and check its pH.
Unfortunately, the other lesson here is that concrete restoration companies plan their work over a year out. Champlaign Towers had finally gotten political consensus from homeowners for a massive assessment to do the work, hired a restoration company, and had been in the queue over a year, months away from the work starting when it collapsed.
The pipe on the left indicates heavy leaking from above.
Clean the calc build up on it.
Find out what is it for and if you can turn it off for a day or two to let it dry up and observe the calc build up. That pipe in question has also some wired attachment to the concrete.
If you can access the top (above concrete) and look for a leak.
