If perfectly centered each of the two adjoining board ends gets at most a inch bearing on the end of the roof truss or rafter.
Fix a board in the edge of my house roof.
This lets any water that gets on the roof run down the underlayment and over the drip edge.
Working your way up the roof expose all of the rotted wood.
Pick up the edge of the shingles that the drip edge lies beneath and drive in a galvanized roofing nail with a hammer.
It should overlap another piece of ice and water barrier laid below all the way down to the roof edge.
If at all possible never nail a fascia board near the edge of the end grain.
In most cases if the shingles go past the drip edge about 3 4 of an inch the shingle edge will break the surface tension unless your roof has a shallow pitch then the water will reach the drip edge and if drip edge is tight to the facia board it will run down the fascia so as added insurance leave space between the fascia and drip edge.
Like the fascia a decaying soffit should be soft enough to pull out manually.
Put one nail in where each.
The best way is to install the roof drip edge only along the eaves first then place ice and water barrier in the snowbelt or felt paper underlayment over the drip edge.
Grab the exposed edge of the board and give it a sharp tug downward to dislodge it.
Nail down the drip edge beneath the shingles.
Then reshingle sliding metal step flashing behind the fascia board the trim behind the gutter.
Lift courses or shingles from the asphalt adhesive strip on the course beneath it to inspect the.
It is possible to get in underneath the shingles on the bottom few rows and remove the nails with diagonal cutters then slip in a strip of same thickness roof sheathing adhered to the rafters with construction adhesive or extra length shingle nails with dripedge flashing put over it placed under the water barrier as applicable.
Find and fix a leaking roof.
You see this all the time where two boards have been joined on the end of a 1 inch rafter or truss.
This should cover the most leak prone areas.
During a reroof start at the peak of the roof and remove all shingles prying them up with a pitchfork working your way down the roof.
Waterlogged boards will often be soggy and prone to crumbling.
Leave the next course of shingles intact by carefully removing the second set of four nails.
Pull up the felt paper underneath the shingles.