I am not much for math.
How to make a roof jack.
Make sure that the diagonal holes on the jack are at the top part of the shingle.
Ideally you should find the rafter first underneath the sheathing locate by feeling the nails.
If the jack does not have an adjustment that will make the walking surface level tilt the jack inward instead of outward for safety.
Drive a nail in each slot and pound it down in such a way that it is level with the metal of the jack.
Then attach the tool into rafter by driving couple of 16d nails.
I was going to do a trash can jack but ended up looking at a roof jack and saying i can make that myself so the hard part is the math and a simple explanation of the math was hard to come by that is what i needed.
Before you install the jacks make sure you have enough of them to form a straight line across the bottom of the roof.
Roof jacks are usually constructed from steel and can be purchased from home centers lumber yards or hardware stores.
Most roof jacks are adjustable to compensate for different roof pitches.
Placing the first roof jack.
I like to build stuff.
Roof jacks provide a stable surface to work increasing safety and making it easier to apply roofing.
You can usually feel sheathing nails which are driven into rafters through the underlayment attach a jack by driving two 16d nails never roofing nails into a rafter.
In my line of restoration work i spend a fair amount of time straightening out the sags in a house that set in over time.
The spacing depends on the width of the scaffolding you use but shouldn t be.
Porch roofs are typical victims of gravity as the roof layers build up and the pier blocks below the porch columns settle.
I could not handle the thought of paying 250 for a roof jack so i started working on an alternative.