I'm about to build a garden workshop/shed 3m x 5m. For the roof I wanted to use super felt as this seems to last approx 15yrs, I can only find 8m or 10m lengths! So the question is, can I join the lengths so I don't have too much waste or is it not advisable. Thanks in advance.
Forget felt look at corrugated roofing like Onduline or metal roofing box or corrugated profile, will last longer, available in many lengths. If you want felt look at 38Kg green mineral felt,only in 10 meter rolls a very thick heavy duty felt.
The extra cost on the sheets will be offset by not having to board the roof on the shed and if you get foam backed sheets it will also be insulated. I would ring round the sheet suppliers as quite often they have "seconds" or "end of run" which they can't use on commercial building but are ideal for sheds
If your budget won't run to the metal, Wickes have an offer on the Onduline. If you do the "topcashback" thing you get another few % off
There are a few referral sites like topcashback and quidco. If you go to these sites first and then click on the link to your preferred retailer you get a cashback reward - Screwfix pay between 1% & 3.2% and Wickes 2%. So if your Wickes purchase comes to £150 you will get a £3 "cashback" which can be translated to cash or increased value with things like Amazon vouchers. So far in the last two years I have had £700+ in cash back from various merchants