Flat roof extension

[eagleeye]

I am due to start a new extension for a friend of mine in the next couple of months and just want to find out the best way to finish the roof. It is a bungalow with a pitched roof. The extension is to go on the side and is to have a felted flat roof. The new extension height needs to go above existing gutter height to get required ceiling height so question is, what is the best way to join the flat roof to the existing pitched roof. I thought of removing tiles to required height and putting felt so far up underneath then replacing the tiles on completion. Maybe wrong but hope you can help me here
Regards

Paul

 

[noseall]

Once you have got the building up to height you will need to remove the soffit overhang that interferes with the extension.

You will also need to remove several tiles above this and the tile battens.
Leave the felt as this will help with temporary weathering.

You will then fit the wall plate to the extension and construct the roof tying it into the bungalow.

You will then fit the firrings (diminishing strips) and insulated deck. You will also then need to fix an 18mm ply lay-deck to the bungalow rafters about 12" above the new roof deck. This will allow the flat roofer to felt up the existing roof a ways.

This extended bit of plywood lay-deck will also need a piece of cocking fillet/angle fillet fixed to it to provide a 'kick' for the first course of tiles as their is no longer any fascia to provide this.

The felt should be lapped up on to the cocking fillet.