Week 10 – Autumn leaves, and the beauty of traditional limewash on stucco

The blue skies of autumn at the Baths of Caracalla in Rome

This past week we enjoyed gorgeous autumn weather here in Rome – sunny days, cool nights, and crisp blue skies where everything appears remarkably in focus.  The good weather this past week compensated us for the week prior, where it rained almost non-stop.   The olive harvest continues here in central Italy – for anyone with a large orchard, the olive harvest may take much of the month of November.   Here at the Academy, with only a couple dozen olive trees in our garden, it was over in a couple days.  Despite the small size of our orchard, we now enjoy “olio di oliva nuovo” (oil of new olives), pressed from our own olives, on several dishes at lunch and dinner.   If you like olive oil, there’s really nothing that compares to olive oil that has just been pressed – it is to a good olive oil in a bottle as just-picked, vine ripe garden tomatoes are to good canned tomatoes. 

The fleets of large tourist mega buses and the attendant throngs of tour groups led by umbrella-wielding tour guides (abundant in late summer and September) are now thinned to a relative minimum.   The lines at museums are now much shorter.  It’s a great time to be in Rome.   The days are also much shorter than in September – sunset is around 5:00 Pm, which makes these beautiful, crisp, sunny, fall afternoons feel even more precious.  The rainy season of winter lurks just around the corner…

Speaking of rain, I’ve been noticing the effects of weathering on the traditional limewash finishes on the stucco surfaces of many buildings here in Rome. 

The cliffs of Roussillon France, where many iron oxide pigments are made. The oxidation (rusting) of iron oxides in the clay gives them their striking earthen red, orange, ochre, and yellow colors.

For anyone who’s not familiar with limewash (it’s currently uncommon in the United States, but very traditional for stucco buildings here in Italy), it’s a natural colored-wash for stucco (or even brick) that consists of lime, water, and a natural iron oxide pigment.  The iron oxide pigments come from natural clays containing iron oxides, which give these clays their earthen color pallet of ochre, umber, sienna, terra cotta, etc. that are common colors for stucco in Italy (and France).   Since brick, clay roofing tile, and the iron oxide pigments used for limewash all derive naturally from clays, it creates a very harmonious pallet of natural earthen tones between the stucco, the clay tile, and the brick, that has become the quintessential picture postcards of rural Italy and France.

The subtle variations in color and mottling of an autumn leaf in the Bass Garden at the American Academy

Aesthetically, a major difference is that a paint or coating will tend to give a totally uniform color, whereas a limewash will give you subtle variations in color, that will continue to vary and weather as it ages.  It’s kind of like the subtle variations in a naturally tanned, rustic leather satchel or jacket that gains character with the variations in color it gains from wear, as opposed to the uniform look of a brown nylon or vinyl jacket.    Or the subtle variations in the blue of any old pair of denim blue jeans, versus the uniformity of the blue of a pair of polyester slacks.  Or the variations and grain in stained woodwork, as opposed to the uniformity of color of woodwork that is painted brown.  Thus the look of a limewashed stucco is less like the look of a painted surface, and far more like the look of worn leather, or stained woodwork, or an autumn leave – in that its beauty comes from the subtle variations in color that add an element of richness and depth to it.  A painted stucco surface is completely uniform in color, and doesn’t have that subtlety or variation and mottling.  I’ve found this aesthetic ideal of some desirable degree of variation in color to be a very difficult concept to convey to American contractors, and even some designers, because they are used to thinking the way paint and coating manufacturers think and market their products– that complete uniformity, and the ability to cover and “hide” variations in the underlying material are always the most desirable characteristics.   And their notion that any variation in the final color is a defect or error that we should all seek to eliminate.  It makes it difficult to convince them of exactly why you would want something that is not completely uniform or consistent in appearance.   They keep saying things like, “Let me get this straight, you WANT it to look blotchy???”    

While it’s often a difficult point for me to get across, sometimes I’m very fortunate and have clients who get it immediately, without me having to say it twice.  For example, shorthly before I left, I was working as stucco and envelope consultant to Anmahian Winton Architects (Nick Winton and Aaron Bruckerhoff) and Brown University (John Cooke) on historic Rhode Island Hall at Brown, and to their credit, as soon as I explained all this, they immediately “got it”, and they knew they wanted some subtle variations in the color of the stucco on that historic building, as with a stain or limewash, and that they did not want the completely uniform look of a painted stucco building.

When Cristina Puglisi, Adele Chatfield-Taylor, and others from the New York office of the American Academy in Rome conceived a major rehabilitation and restoration of the American Academy’s McKim Mead and White Building in the late 1980’s, they chose to use a traditional limewash rather than a contemporary paint or coating.   In my opinion, the building looks far better today for their choice.

The traditional limewash finish on the stucco of the McKim Mead and White Building at the American Academy has a subtle variation in color that gives it richness and depth.

To illustrate the basic difference in appearance, I’ve compared photos taken of the American Academy in Rome, which has a traditional colored limewash finish, with the American University in Rome (our neighbors diagonally across our side street), which has an acrylic coating finish on the stucco (similar to what would often be used in the U.S.)   Although both finishes date from within the last 25 years, and although they both went for the earthen red, orange, and yellow tones that are common for stucco here in Italy (because of centuries of use of natural iron oxide pigments with those colors), you can see the difference in appearance, and see how difficult it is to imitate that natural earthen pallet in an acrylic paint or coating, as the American University building shows.  Even computer color matching of a chip from an old finish doesn’t get you there, because it still gives you a single completely uniform color, not a subtle variation.

The contemporary acrylic finish coat on the stucco of the American University gives a completely uniform consistency of color, without variation.

Technically, a limewash behaves much more like a stain than like a paint or a coating.  The key technical difference between a stain and a paint is that a stain does not form an appreciable “film” on the surface, whereas a paint does.   This has pros and cons.  Like a stain, a limewash won’t repel water as much as a paint, but when the underlying material (e.g., stucco or masonry wall) does become wet or damp, it will dry allow it to out much more readily than a paint will.  Essentially, it’s easy-in, easy-out for moisture. 

Blistering paint on the stucco surface of a wall, at an institute on the same street as both the American Academy and American University

Conversely, when water is trapped behind a film-forming coating like a paint (even a “breathable” paint), it will tend to peel or blister.  Thus, when an historic masonry or stucco-clad building has never been painted, it’s important to realize that even a “breathable” paint or coating can change the way the wall has been behaving (and drying)all these years.  It doesn’t mean that you can’t ever paint the exterior of a traditional masonry building, but it does mean that you need to analyze it carefully, looking at the entire wall section, to make sure you’re not going to create a new problem that never existed before.  

A non-film forming stain or limewash won’t blister or peel, but it will slowly fade, be absorbed in,  and/or wash off the surface over the years as it weathers, and thus it needs to be renewed periodically.  Unlike a paint, since a stain or limewash doesn’t peel or blister, it won’t need to be scraped as part of the preparation for a new finish, so this renewal becomes alot easier than with paint.    As someone who painted houses for several years while in college, I can tell you that applying a stain or paint is easy, but what’s really hard work and a pain-in-the-neck is scraping a peeling paint or coating.  This you won’t do with a stain or limewash.   It’s also one of the reasons (along with the aesthetic subtlety of variation in color and texture) that when I reshingled my house back in the States, I used a stain, not a paint, on the wood shingles.

The way in which limewash weathers over time (and slowly fades and eventually seeps into or washes off the stucco) creates some interesting chances to see the effects of weathering, and subtle microclimates, on façade surfaces with very old limewash finishes.  I’m just about out of time and space today, but I’ll show some examples of these observations next week.