We offer the best selling Internal Walnut doors in the UK, Whether you are looking for a traditional look, or cool, more minimalist decor, were sure our internal walnut door range will inspire you. Rich and warm, or stylish and sleek, walnut is a beautiful versatile finish that we are pleased to offer you. All our walnut internal doors are Pre-Finished and are 35mm in thickness for your imperial sizes, 40mm thickness for metric sizes (2040mm height doors) and finally 44mm thickness for your Walnut Fire Rated Doors. Enjoy taking a look through today. £10 Off At Checkout When You Order 8+ Doors.