Has anyone come across this type of insulation before?  while making the parents extension, we discovered it in the walls and attic. the property was built around 1973 and I wonder if this was a typical insulation to use then.  I was working on the new doorway today and the insulation was falling out of the exposed cavity.  I was wondering what type it was and elderly mother just said 'Oh, thats kapok!'.  she is not a builder and I was amazed she had any idea.  is she right?  it is very light and fluffy but with a slight roughness to it. 

Google mentions kapok as an insulation but not for housing. 

this is a good web page for info on the stuff.

http://www.wildfibres.co.uk/html/kapok.html

this is the seed pod which contains the fibres.