I have just installed some 200mm insulation (over the thinner insulation already there) in the eves of the loft as the centre is boarded over for storage. We hope to have the old slate tiles renewed next year as we get a lot of dust and mortar falling off them they are so old. In the meantime I was wondering if sheets of bubblewrap could be placed over the new insulation to stop dust falling onto it as well as any possible water leaks that may fall onto it and spoil it. Also, could the rest of the loft have it attached with drawing pins temporary to the wooden roof frame to stop further dust falling in as well as insulating the loft further until the tiles are replaced ? My brother in law did the same with his roof except he used thin polystyrene sheets which has made a huge difference to his fuel bills.