My façade was old & cracking. Chunks looked like they were close to falling. I removed all the loose bits and re-rendered with new concrete. I did the proper bonding steps with polyvinylacetate (#PVA). That previously cracked part of the #façade seems relatively strong and water resistent now (i.e. the color remains light colored and slightly shiny even after rainstorms).
There were old parts of the façade that I did not touch because there were no significant cracks. But these old untouched areas appear to absorb water. They are always wet looking. They only appear dry if there is a quite long stretch of no rain. I think it takes several weeks of mid-summer dry weather before the water evaporates. I think the constant moisture will shorten the life of the affected areas and the moisture is apparently getting into the house as well.
anti-stucco paint school of thought
Painting #stucco is controversial. Some people insist on it, and some say stucco is meant to “breathe” and should never be painted.
I’m personally in the anti-paint let-it-breathe camp. However, I think my situation is a bit exceptional. Perhaps the original stucco was not the right stuff. It’s too porous. Re-rendering seems to have a high cost/benefit.
As a hack, I am tempted to prime and paint the part of the façade that appears to be holding water. I would like opinions on this as well as alternatives. I would also like to know if any exterior paint will do the job or should I look for paint with waterproof properties.
Note that I do not care much about cosmetics. I just want to reduce the water ingress but ideally without suffocating the wall too much, if possible.
Never try to keep water out of a building using impermeable coatings, rubberised paint, ciment render, etc etc. A building MUST breath, even at the cost of some inward moisture during wetter periods, any water that will inevitably creap in,and even the moisture you create by living in the building,needs to escape, or I guarantee you will have mould and rot problems down the line. Water which can not escape from behind an impermeable coating is worse that no coating at all. I recommend a lime render for all building needs.
Thanks for the suggestion.
When it rains sometimes it drips water along the top interior window frame. One one occasion water collected behind the interior wall paint and formed a water balloon. I took a guess at how the water was entering and corrected it. But even after that I still have water dripping from the top window frame.
I like the lime idea. Lime comes in many forms (e.g. quicklime, hydraulic lime). I’m not sure I’d be keen to work with the stuff that needs a complex number of steps with a mixer that can withstand heat. Suppose I buy “white lime” (which is marketed as a whitewash for trees as an anti-pest control, and for cosmetic changes on brick walls). Will that do the job? I think I simply mix it with water. How do I bond it? With PVA?
(edit) Since I guess you speak French, perhaps you can tell me if this stuff is right for the job:
https://www.espace-emeraude.com/chaux-blanche-white-lime-2-5-kg.html
^ I have some of that stuff already on-hand but it was opened ~14 months ago, so it might be oxidized into chalk. I’m not sure how to test to see if it’s still usable.
It appears the #Cantillana varieties of lime render are simply rendered on with no bonding steps or additives.