In his series of articles highlighting technical issues to do with wood flooring and woodcare, our Technical Manager Richard Aylen explains how wood dyes and colouring processes work
One of the many reasons why beautiful timber floors have been around for so long is that they blend perfectly with many styles of interior. In common with other natural materials, timber may be used next to a wide variety of other colours and textures. The colours that nature provides are very familiar to most of us, but we can create even more choices by using stains, textures and colouring processes.
What options are there if you’re looking for a floor with a coloured finish? It might be a new floor or refurbishment of an old one – there are a few popular choices, each with its own pros and cons.
For refurbishments, a decision must be made if the products to be used will be from one manufacturer that are guaranteed to work together. Alternatively, there is the option to “mix and match” using wood dye from one supplier and lacquer from another. If the latter method is chosen, the flooring contractor needs to guarantee that the products offered are compatible. If in doubt, always do a test area and be aware of the risk that manufacturers sometimes alter formulations… so what works today may not necessarily work tomorrow. The timber species may also affect the result. Some water-based finishes may not perform well on naturally oily tropical hardwoods, but will be perfectly fine on traditional species such as oak and ash.
Let’s look at some of the choices that are available for customers who want to add colour their floors.
These will usually be water-based and used instead of a clear primer. As well as providing the desired colour, the primer will reduce the “gluing effect” that can occur with water-based finishes. A good, and very popular, example is Junckers Prelak White.
Primers provide an even, transparent “wash” effect and work well on wood that may have a patchy finish if a conventional wood dye is used e.g. maple or beech. Skill and care are needed during application to avoid overlaps, especially on darker, parquet style floors. The primer needs to be over-coated with clear lacquer and it is safest to use a lacquer recommended by the primer manufacturer.
Not strictly a coloured finish; “Invisible” primers and lacquers are fairly new to the UK market. They are used where the final colour of the floor needs to be as close as possible to bare sanded wood. Their “invisibility” works in two ways; one, that they have a very “flat” matt surface which gives the impression that the wood has no coating. Secondly, they change the colour of the wood very little. That said, these are often normal properties of many water-based primers whether marketed as “invisible or not. Best results are achieved on light coloured timbers as some colour change will be seen when applied to very dark woods.
These are low-solids, fast drying products, not to be confused with coloured varnishes or “wood stains”. They must be protected with lacquer. The “rule of thumb” is that if the wood dye is organic solvent-based, a water-based lacquer is most likely to be suitable for overcoating, and vice versa. This must not be fully relied upon though, and a test area should always be done prior to treating the whole floor. Often, the lacquer used to over-coat the dye will be from a different manufacturer.
Dyes are easy to apply using a cloth or pad and it is fairly easy to avoid overlap marks etc. They are fast drying, so the first coat of lacquer or primer can be applied soon after. Bear in mind that stained floors may be difficult to patch repair – especially if the colour has faded over time and may appear patchy on certain types of wood eg maple, beech.
Oils often produce a uniform colour on beech, maple etc. compared with wood dyes. They tend not to be prone to application issues such as roller stop marks and work well on herringbone and parquet floors. Oil can be used on its own or may be used as a primer and then over-coated with lacquer. Check that the oil is compatible with lacquer – some are not. Junckers Rustic Oils may be used either as a full treatment or over-coated with HP Commercial lacquer. Oils tend to have a longer drying time than a primer or wood dye.
The Effect of Sheen
Many customers will prefer matt finishes on textured and coloured boards as this tends to look more natural, although this is largely a matter of current taste.
Vacuum coloured floor boards
For a very consistent and permanent coloured finish, some types of timber lend themselves well to vacuum staining. Here, the colour of the wood itself is altered by using a chemical or staining process. This affects the board through the majority, if not all its thickness. So when the floor is sanded there is no need to re-apply the colour treatment. Fumed oak, or Black Oak, is perhaps one of the better-known examples of this. Junckers has also used this process on beech to make its Sylvaket boards, and has extended the process further by vacuum staining with water-based wood dyes.
The ever-increasing choice of finishes has led to an increased demand for ‘the perfect shade’, a perfect match to another design element of the interior. It’s always important to assess the use of the floor, estimated foot traffic and maintenance issues before recommending one choice or another – that’s where the expertise of a professional flooring contractor comes in. Our network of Approved Flooring Contractors and Approved Maintenance Contractors might be able to help!