Back in the 1980’s there was a bit of a craze for using terracotta. It was everywhere, in magazines, on TV, and it was soon being used extensively in homes and also in commercial properties like pubs and wine bars. After a few years it seemed to disappear almost as fast. This is due in part to the over-exposure and the ever changing fashions for interior design, but I also suspect that more than a few people experienced a number of headaches in terms of sealing, cleaning and maintaining it.However, all things work in circles right? Well not exactly, but I do see that Terracotta is making a little bit of a come back, not like the last time, but people are it seems one again being swayed by the rustic charms and warm tones and using it in selected areas.
So, I though it timely to do a little article on the methods for sealing terracotta. There are basically two systems (and lots of variations for both) :
1. The traditional oil & wax treatment, or,
2. The modern, synthetic approach.
1. Traditional Oil & Wax.
Many Tilers still prefer this method, largely I think because this is the method they were taught. One of the most popular methods for sealing terracotta is to use a combination of boiled linseed oil and then polish with a neutral Beeswax.
First the tile is treated with several coats of boiled linseed oil; the oil is spread with a cloth or sponge as evenly as possible over the terracotta, before grouting. The first coat is the hardest as the oil is pulled into the extremely porous tile very quickly, so it takes a bit of skill and practice to get an even coat. Subsequent coats are a little easier, until the tile approaches saturation. Care must be taken not to over-apply the oil, making sure any surplus is not left to dry, as this would become sticky and require scraping off. Once the tile is sufficiently sealed (it will take several coats) it will also be considerably darker. It is the oil that gives terracotta that characteristic amber shade that many people like. Once dry, they can be grouted. When the grouting is completely dry, the tiles can be finished off with a coat or two of wax polish – there are many to choose from, some in paste form that require thinning with white spirits (a messy job) and others that come ready to use as a ‘floor wax’.
The advantage of this system is really just aesthetic, if you like that ‘warm look’ then go for this. However, there are several drawbacks: It is a much more involved process in the beginning; ongoing maintenance is also more arduous, the wax will quickly dull through traffic and cleaning, thus it will require frequent re-polishing and this is a hands and knees job, unless you are prepared to purchase a buffing machine. After a while, the wax will build up in layers and will start to actually attract and hold dirt, becoming darker and even tacky to the touch. At this point it needs stripping off, right back to the tile surface using solvent stripers (the oil will not be removed) and the whole polishing process starts again.
2. The Modern, Synthetic Approach
While possibly not offering quite the same depth of colour as oil and wax (it should be pointed out that not everyone likes that artificially darkened colour anyway) is much simpler and far easier to maintain. Again there are several propriety products available. Water-based, acrylic type coatings sealers are safe and relatively easy to use, offering both a surface seal and a degree of shine or gloss in one operation. This saves both time and money. Typically several coats of this type of product can be applied to the tile, depending on its porosity and the degree of sheen you are after. After grouting another coat may be applied. And that is it, job done. As it is a surface coating, just like wax it will of course wear, but it is more resilient and will not dull quite so quickly. With proper care, using neutral cleaners it can actually last for up to 3 years, but typically will not require any topping up before 12 months (this is dependent on many things of course). When it does start to dull down, there is no need to strip; instead a fresh coat can be applied right over what is already there.
If a very glossy finish is required, like a highly buffed wax, then adding a coat or two of a sacrificial acrylic polish on top of your coating sealer will add that high-gloss look. In addition to this, as it is also a sacrificial layer, it helps to protect and prolonging the life of the sealer beneath.
Copyright Ian Taylor and The Tile and Stone Blog.co.uk, 2013. See copyright notice above.