New shed roof

The felt blew off the utility room shed roof more than a year ago. It was old and had become fragile. The boards were too rotten to re-felt and re-roofing looked like a big job so I put it off. There is now some evidence of water ingress inside.

Surprisingly the woodwork underneath is in good condition.

The purlin was undersized and has sagged. It was 3 x 2 (inches) spanning 4m. I’ve sistered it with a length of 4 x 2 cut down at the ends to straighten the roof a little and make it easier to fit the new sheeting.

Removing the roof has angered the rain gods. I was slowed down by the first rain in weeks.

I’ve used OSB for the rood sheeting to match what was there. There are 5mm gaps between the sheets to allow for expansion. There’s a 2 x 1 inch strip of wood screwed under the front of the roof sheeting I can nail the felt to.

I was recommended IKO Trade Top Sheet which is a lot thicker and is much easier to use. All the edges and felt overlaps are glued with bitumen adhesive as well as nailed. The adhesive needs to be applied to both sides of the join.

It was a pain getting the felt to sit on the roof without it sliding off. I ended up nailing a bit of scrap felt to the roof and rested the new felt on that. Once the new felt was nailed on I could remove the scrap felt. It doesn’t matter much if the nail in the scrap felt is at the bottom.

It went a bit wrong on the other side. I applied some felt adhesive early in the morning when it was still cold so it went on a bit thick. Later the sun made it very hot and the bitumen went runny.

The flashing was a pain. In the past someone had cut a big gouge in the bricks and there wasn’t enough brick left for step flashing. I had replaced a few bricks and wasn’t prepared to cut a gouge in them. So I ended up with a compromise.