Sealing is not necessary. Sealing is purely aesthetic, and will darken the color significantly. You may choose to seal SLATE-ish in areas of extreme wear or in locations that might receive moisture on the surface, or if you prefer a darker color or a gloss finish.
We recommend using a spray-on water based polyurethane, though this could be applied with a sponge or brush as well. Other coatings may be suitable, such as herbal oils (like Bioshield). If you prefer to use another type of sealer, please test an area first. Gloss finishes tend to make the tile look more synthetic – a matte finish is more similar to actual slate or other natural stone.
Color variations are inherent in this material. Because our material is recycled and from various sources, the color may be different than representative samples. Different manufacturers, batches, and sources can result in differences in color tone, visible layering, and texture. We recommend mixing tiles in each shipment to assure even distribution of these variances. If variation has to be eliminated, contact us for details on additional charges for producing an entire job from one sheet of material. This is possible, but may require that we purchase new, non-recycled material.
The paper-laminates used to make SLATE-ish oxidize over time, darkening the color, whether the tiles have been sealed or left raw.