DuroGrit is a one-layer product. When two or more coats are applied, there is a chance that the second coat will not adhere, allowing it to easily scratch off. However, in exceptional cases, e.g. very grey/weathered wood, a second layer might be necessary for aesthetic reasons. The first layer will act as a primer, but due to the high and inequal absorption of the wood, a second layer will provide a more uniform colour. In these cases, we also advise diluting DuroGrit with 20% of water.