Wooden windows will only have a long term lifespan if they are properly designed and protected. Corner joints of windows are always subject to stress. At these points the timber is moving in different directions, which can lead to open V-joints. We at Eurotech WinDoors® seal these V-joints with a special formulated Sikkens sealant that allows the timber to expand and contract. In addition all endgrain of the sashes are sealed with a Sikkens endgrain sealer.