Techniseal® wood preservative is a clear, penetrating fungicide designed for the protection of new or old untreated wood prior to the application of a sealant, stain, paint or varnish. It is ideal to touch up end cuts on pressure-treated wood or to fully protect untreated wood. Equally effective on vertical or horizontal surfaces, it extends the life of decks, fences, siding, pergolas, balconies, shingles, quays and more. Made of zinc naphthenate, Techniseal® preservative protects wood against mildew, rot and fungus caused by water and dampness.