The shingles will roll up like a ball in front of the fork.
Removing roof tiles from inside.
Start on lowest row of shingles and work your way backwards to the upper part of the roof.
Continue spraying until you see runoff then let the chemicals sit for 15 20 minutes to soak in and begin attacking the mold.
Once you have safely gotten to the broken tile you ll need to slightly lift the tiles that overlap the one to be removed.
This video from bunnings shows you how to take a tile off and replace it prop.
70 years is more than enough time for any roof especially if it has clay rosemary s on it and it sounds like they have blown.
This video shows how to replace an interlocking roof tile such as the marley ludlow major or the redland renown.
This maneuver will help to remove the piles together with nails.
If you are removing any tiles from your roof it is a great idea to store them for use in the future.
Remove shingles in a 2 to 3 ft wide section as you work down the roof.
There is obviously no felt on the roof either so it looks like you are going to need a new roof.
Spray the entire roof thoroughly.
This will prevent the solution from draining in your direction.
Unfortunately roof tiles cannot be replaced from inside.
Answered 22nd jan 2016.
Work your way through the top row of tiles weakening and pulling them.
I d tend to agree with agl above.
That way you can be sure you have got an exact match if you need to replace a tile later on especially if your roof is a bit older.
Push the shingles down to the roof jacks.
Remove tiles from the roof ridge first.
Working with roof tiles is a lot easier when you know a couple of basic tricks.
Keep your old roof tiles.
Continue tearing off the shingles and underlayment until you reach the roof jacks then start over at the top of the roof.
If you do not have a scraper use a garden spade with a flat blade to hook the tiles underneath.