Posted: 28/05/2014 at 09:07
Perhaps it would be apt to add this to this thread.
The cheap mineral felt sold & used for shed roofs has a very limited life.....it usually succumbs to high winds or rotting after a very short while.
I have a large/ish shed and summerhouse, both were felted as above when new. When they needed re-felting, I decided to have them both 'hot felted' by professional roofers...it cost £100 per building and came with a 25 year guarantee.
The process involves the roof being stripped clean, an under-felt being applied, this is heated & melted with a flame-gun, next a heavy duty mineral felt is laid on to this and both are fused together, again with the flame-gun.
No nails are used and it's a really neat job.