Problem solving primer from Classidur
It seems that the world and his wife now have a problem-solving primer for every occasion. But for as long as I have been in the trade, the market-leading brand has been Classidur, made by a Swiss company called Claessens. By 2003, their range of easy-to-apply problem-solving paints had been applied to over 1 BILLION square metres world-wide.
This post has been updated Dec 2013 to reflect the changes in the Classidur range and the distribution of their products in the UK. New product names will be shown in bold type
Considering its popularity on the continent, only a small number of UK restoration contractors, maintenance firms and decorators are familiar with the Classidur range. Interestingly, though, one of the brightest stars from Classidur, their Universal Primer, was right under our nose since 2000, in a tin labelled “Blackfriars Problem-Solving Primer”.
(The Classidur own brand primer is now an improved version known as Universal Primer Extrem and is available from Magic Bullet Coatings in Nottingham.)
Classidur’s water-based Universal Primer is good for sealing sooty, chalky or nicotine-coated surfaces prior to further decoration with conventional paints. Plus, it is an adhesion primer on wood, old undamaged paint, glass, non-ferrous metals and, after testing, on hard plastic materials such as plastic-coated, stained or varnished substrates.
From first hand
– Classidur Universal Extrem primer is user-friendly, with a particular Swiss innocuous odour.
– As a “wash coat” on new plaster, it gives you a base coat that cannot be beat. (Using a 3/8 pile roller)
– It would be my top choice water-borne problem primer when painting pine furniture. It primes straight over knots, and sands down super smooth.
– It has got me out of trouble with damp stained ceilings where Zinsser Bullseye 1-2-3 failed miserably.
– Although it is a primer, it will dry to a lovely matt white finish.
– If you have a patchy, problem wall, you may never get a flat, even finish with conventional vinyl matt or superflat emulsion (I have seen walls painted by contractors with 5, 6, 7 coats and still look patchy!) But one coat of Universal Primer Extrem obliterates your problem porosity and patchiness, and the basecoat cuts out all worrying about whether subsequent finishing coats of emulsion will cover and dry evenly.
But there is more to Classidur than their primer.
On the continent, painters have coated literally hundreds of millions of square meters of problematic wall and ceiling surfaces with Classidur products. Their strength lies in the ability to produce a dead flat matt white / lightly tinted finish in 2 coats.
To repaint a fire-damaged plaster wall or ceiling the spec is essentially “remove loose material with a vacuum and apply 2 coats of Classidur
Golden Classic SuperClassic!”
Restoration specialists in UK prepare and apply Classidur SuperClassic (oil-based) or Classidur Aquaclass (water-based) in churches and historical buildings. 2 coats to the walls and ceilings, job done.
High-end commercial decorators apply Classidur coatings to the huge ceilings in concourses. It dries dead flat even, whereas standard matt emulsions on plaster finishes that are less than perfectly smooth can look patchy, regardless of how many coats you apply.
Classidur products are inert
The most distinguishing (and outlandish) aspect of Classidur products is that they are inert. If I have understood it correctly, they are substrate agnostic! ie they don’t rely on the surface they are on, to form a film! So it doesn’t matter if the surface is sooty, or nicotine-stained, Classidur finishes will dry in their own sweet way to form a uniform pure matt white coating that stays intact and white, regardless of what is going on underneath.
To get my head around the idea of an inert coating, I checked out a demo plastic sheet painted with Classidur. The film is solid, doesn’t scratch, and flexes with the plastic. And it won’t crack, because the Classidur doesn’t rely on the plastic for its integrity as a continuous film. And like the rest of the best problem-solving primers on the market, it doesn;t have pigments that react to damp or nicotine or salts, so, it stays pure matt white.
Downside of Classidur products
You can paint over the Universal Primer Extrem with any single pack water-based or oil-based paint, however, it is advised not to paint over Classidur finish paints eg SuperClassic, Aquaclass etc with anything other than Classidur finish paints. The main reason for this is not immediately obvious. Speaking to Promain, if you paint vinyl matt emulsion on top of Classidur, it won’t react or delaminate, but what you do lose is one of Classidur’s best properties – its extreme microporosity. Classidur products are almost a non-coating, allowing practically all moisture to pass through. So any other paint that you apply over the top, diminishes this most important property. So you can over paint Classidur finish paints, but you end up with a less breathable surface. Whether that matters is debatable on most jobs.
You can tint Classidur finishing paints, but according to expert supplier Papers and Paints of Chelsea, you are restricted to very pale shades. Also it is best to “box” ie mix together sufficient tinted paint to complete a room, to avoid shade differences.
Classidur products look expensive at first glance – £136+VAT for 10 litres of Aquaclass, which is roughly enough paint to turn a room 12′ x 12′ from a hellish nicotine-stained ceiling and walls into a white heaven!
It may sound a lot, £164 for white paint in an average room, but what is the option? Using conventional paints you would pay about £100 for 5 litres of Zinsser B-I-N shellac based sealer to seal the nicotine stains. It is a very noxious smelling product and cleans off in meths ie you need to also account for throwing away your roller sleeve (£3-£10) after the room is sealed. Once sealed, allow an absolute minimum £50 for ceiling paint and wall paint. You also have to allow for the cost of labour applying 3 coats of paint.
£153- £160 for materials plus 3 x labour
£164 for material and 2 x labour
So, in this situation, it makes more sense financially and logistically (time savings) to paint the room twice with £164 worth of no odour water-based Classidur, than 3 times with cheaper paint using conventional methods. I was reading a comparison for a particular job where using Classidur v traditional methods is 30% cheaper. The bigger the scale of the problem, the bigger the case for Classidur.
Convenient, ultra reliable and nice. That is why painters on the continent like Classidur!
Classidur in the UK
If you are curious about the Classidur range, I highly recommend taking a look at the Ptarmigan website. Dominic Taffe is the UK representative for Claessens and is at the core of all things Classidur in this country. There are many nuances in the product range and it pays to hear the pros and cons from the top.
Classidur equivalents? Zinsser Grade 1
I am looking over the latest product info from Zinsser, the Grade 1 which looks like it is supposed to “match” Classidur. It comes rather interestingly from the former exclusive UK distributors of Classidur, a company called Tor Coatings. Wonder what they were doing with a few spare tins and a chemist? 🙂
Zinsser Grade 1 is pitched as a solvent-based low odour paint, one or two coats, job done, problem-solver for renovation work. There are a couple of characteristics to note, however, bearing in mind that Classidur Tradition is a 2 coat straight onto anything product.
Zinsser make no claims that Grade 1 will go over soot.
Over smelly substrates, it is best to seal first with Zinsser BIN shellac primer sealer, before top coating with Grade 1. This must be to hold back odours that Grade 1 can’t hold back when the heating goes on.
Keep the lid on tight as it is prone to skinning over.
Over clear finishes, pre-prime with Zinsser BIN
Over knots and resin, spot prime with Zinsser BIN, full primer of Zinsser Allcoat, followed by Grade 1.
It may need a bit more research before jumping in with this one.
Elite Heritage is another Classidur Tradition killer
I have not used it, but it seems to be closer to a like-for-like product. It is even zero-tension, applies over soot.
It is available from the Spray Shop.
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