If the boarding below the felt is still in good condition I would re felt
the roof, depending on the felt you have on there now, you might be able to
felt over what you have, using a good bitumen and new felt.
..
I recently refelted a 24 X 19ft roof cost was around £40.
--
David Hill
Abacus Nurseries
www.abacus-nurseries.co.uk