The Tiled Roofing Consultancy Ltd
recommends these links for further information:

Link group
Ardelis LLC Manufacturers of SlateSpacers and other products
http://www.slatespacer.com

Building Regulations Communities and local government department web site
http://www.communities.gov.uk

Cembrit Ltd Fibre, cement and natural slate suppliers 
http://www.cembrit.co.uk

The Institute of Roofing ( IoR) The roofing industry professional institute
http://www.buildingtalk.com

Klober Roofing accessory manufacturer
http://www.klober.co.uk

Marley Eternit Clay, concrete, fibre cement and resin slate manufacturers
http://www.marleyeternit.co.uk

Manthorpe Building Products Roofing accessory manufacturer
http://www.manthorpebuildingproducts.com

Redland Monier Roofing Clay, concrete, natural and resin slate manufacturers
http://www.monier.co.uk/

Roofconsult Roofing Information site
http://www.roofconsult.co.uk

Roofinfo Roofing services directory
http://www.roofinfo.co.uk

Roofing Cladding & Insulation Magazine (RCI) A roofing magazine
http://www.unity-media.com

Sandtoft Roof Tiles Clay, concrete and resin slate manufacturer
http://www.sandtoft.co.uk

The Clay Roof Tile Council (CRTC)
Clay roof tile manufacturers trade association
http://www.clayroof.co.uk/

The Concrete Tile Manufacturer’s Association (CTMA)
Concrete tile manufacturer’s trade association
http://www.britishprecast.org