This is done with the use of what is a t bar hanger it is a hidden hanger with an attached strap the is secured to the roof deck.
How to install gutter strap hanger without fascia.
This page address the installation of gutters with a home that does not have a fascia board to attach the gutter to.
Side rafter brackets are galvanized metal arms which are fixed to the bottom side of your rafters.
If the roof is older it is not wise to try and lift up the shingles to get the strap under because you can damage or break the shingle.
Hopefully the photo will illustrate the problem.
The roof straps are fitted to the hanger in the gutter and attached directly to the roof.
Side rafter brackets these are currently the most popular alternatives for installing gutters in properties without a fascia board.
A home without fascia needs to have gutters attached by roof straps.
The gutter is then suspended from the roof with this installation a tie back strap should be installed as well.
A house without fascia needs to have gutters set up using roof straps.
I have a roof that only has a sort of moulding that transitions from roofing to the walls.
A house without a fascia the piece of wood below the last shingle has to have gutters installed using roof straps.
If the roof is ancient then it would be wise not to lift up the shingles in a bid to reach the strap under because it could rupture or break the shingle.
These straps act as a sling for your gutter.
The answer is roof straps.
They re fitted to the gutter hanger and then they are attached directly to the roof.
The roof straps attach to the hidden hanger inside the gutter and secure right into the roof.