Portland Roach stone is a cavernous, shelly, oolitic limestone which, because of the high shell content, has a colour closer to grey/creamy white rather than the creamy white of the other Portland Limestones. It is a very hard and extremely durable material and is therefore ideally suited to exposed sites. The pronounced shell structure has also encouraged its use as decorative flooring or cladding panels.
Portland Whitbed is a fine grained limestone containing shell fragments distributed randomly and in bands throughout its mass. It is the traditional general building stone, being both extremely durable and able to be used for intricate masonry.
Portland Basebed, also known as Bestbed, is the finest quality Portland Stone with a close pore structure and little shell. The stone is slightly less durable than Whitbed or Roach, and therefore may not be appropriate if a long life is required as a general paving stone, or in areas of very high exposure. Although originally used primarily as a monumental stone and carving stone, it has more recently been specified on high quality, prestigious office developments and used extensively for flooring.