Wter stains can be a persistent issue in older buildings.
Salt hydrolysis I'd real, and can become damaging to you building (see our 'salts damage' page for more detail).
We are going to start with a brilliant old quote from Socrates
that we think is so very true:
"I cannot teach anybody anything. I can only make them think
The name Zinsser is becoming a one size fits all name that We're seeing used everywhere today, and it concerns us.
The company was formed in 1849 so it certainly does have a long and good background, however what concerns us is the vast number of peopple simply pumping out the name Zinsser for pretty much anything related to Painting:
Stainblocking '- Zinsser
Priming - zzinsser
Finish coating- Zinson.
And on, and on,and on.
Zinsser have certainly produced some good products over the years, and in no way whatsoever are we suggesting that the brand itself is not good, but it needs understanding as it's most definitely not the 'magic' product that too many today think it is, and it's limited where period, traditional and listed buildings are concerned.
Althkugh they really began by producing Shellac based coatings and this is what became their wonderful stain blocking paint, wevhave puy some pics of dpsome of fgeir range of pfoducts, to give you an idea of their journey to where they are now
Now. Back to good old Newton and his laws:
Newtons 3rd law of motion states: "for every action there is an equal and opposite reaction"
So to put the stain blocking assumption into reality: every stain will have been caused by something, therefore by definition every stain is unique, but a one size fits all paint coating is not the answer to every individual stain, despitecarm chair experts thinking it is. People really do need to understand what has actually caused the stain; in older builds it's very often water staining, so according to the arm chair experts all you need to do is to open a can of Zinsser stain blocker, slap it on the stain, and it's as easy as that!
But the whole area has been affected by that water, due to porous building components absorbing and trasferring moisture through capillart action, so how does that moisture then naturally escape once Its path has been blocked by the stain blocking paint?
The answer is simple: it just continues to travel through the absorbent building elements by further capillary action until it can find an exit pathway out ofp (we'll use walling for an easy example) your walling. So baring in mind that this moisture will gather up more contaminants along it's travels, you will end up with another stain further along your walling (so an equal and opposite reaction has occurred) but that's OK because you know that all you need to do is slap some more Zinsser over your new stain, because it worked the last time!
But one day, when your room looks likeMr Blobby has been bouncing around your walls, the realisation will then kick in and then the full repair costs will kick in, but of course the repairs are not only surface repairs, deeper repairs are needed because the intergrity of your walls has been affected by the water/moisture travelling through them and carrying all the muliple other elements they picked up along the way
So whilst the arm chair experts are quick to promote Zinsser's exceptional stain-blocking qualities. They fail to mention the down sides! Maybe they only see one arm of their chair and never look at the other arm.
Buy a can of oil based undercoat instead (yes, of course, linseed oil; olive oil goes on salads, cooking oil goes on your roast potatoes, engine oil goes in your car engine, linseed oil is thevonly oil which. goes in oil based paints, in the same vein water goes into emulsion paints so there's water vasedvpaints and oil basedvpaints usedvin the domestic market in the UK there really is no need for the word 'linseed' to be continuously used.
We started by mentioning that Zinsser stsrted out using Shellac:
Shellac is a resin secreted by the female lace beetle predominantly native to India and Thailand. It is found on twigs and branche
Ppps of trees frequented by the lac beetles. It is processed and sold as dry flakes and dissolved in industrial alcohol to make 'liquid shellac'. The alcohol evaporates quickly, leaving the shellac itself to transform from a liquid state to a dried solid which is highly impervious and thisvis what creates the 'stain blocking' properties of Zinsser's stain blocking paints. And also which prevents moisture from naturally evaporating out of your walls.) Whereas the oil based undercoat blocks staining, predominantly due to its high bulk of pigments, but naturally retains it's abilities for moisture to escape through it, once the 3 Stages of drying have completed: 1) Evaporation (of the solvent) 2) Oxidisation ("air drying of the paint film surface) and finally 3) the Polymerisation (where the pigments, the binders, the liquid driers and the linseed oil all chemically combine to form one hard, dried, microporous paint film.)
We know which one we choose everytime, suffice to say we don't remember how many decades ago it might have been when we might have last bought Zinsserr!
We think there are an awful lot of armchairs that could benefit from being coated in shellac these days, to prevent the occupants from writing continuous ill educated nonsense online 🤣
Occassionally we still make our own shellac paints., but we also use shellac flakescand isopropyl alcohol to make our own French Polish, just as we did when we started out back in the middle ages! Back in those days paints were not as plentiful as today so we had to learn how to make v
our own paints, glazes and finishes. We had fully equipped labotetorys with regular sciience classes weekly, and thisviscwhybwexarecasamant that only real Decorators can Decorate. Aftervtye great shake up in the 80's where NVQ's came along we watched all of the science labs being turned into classrooms, and Sciences simply fizzled out shortly thereafter, so there is a very big difference between us older generations and the more modern generations (we cover more on our "finding trades" page if you are interested)
So Hopefully we've honoured the great Socrates by giving you something to think about?
