Marie- I know you are getting terribly frustrated and you must be exhausted by now after fooling with this all day and you are prolly confused by all the conflicting advice you are getting. I SWEAR to you- what you are trying to make is known as Flying Geese. The second method shown on this page- link below- called 'speed piecing flying geese'- is what you want to do.
Use a rectangle of the roof fabric cut exactly at 2-1/2 in. X 1-1/2 in. Then cut 2 squares of the sky fabric at 1-1/2 in. X 1-1/2 in. This will give you a final raw unit of 2-1/2 X 1-1/2 and finish up to 1 in X 2 in. like you said you needed. You will NOT cut any triangles with this method and it WILL produce three triangles all sewn together with appropriate seam allowances and sharp points.
Lay one square right sides together and match it evenly to one end of the rectangle. Then use this method on the link to sew exactly across the diagonal of the small square from the center of the unit at the corner of the small square to the outer corner of the small square.
After you stitch this first diagonal, fold the sky fabric back into the corner, trim off the underneath triangular shaped fabric at 1/4 in. from the sewing line and then lay the second square on the other end of the rectangle and sew across the second small square on the diagonal in the same manner.
The seams WILL cross in the center of the rectangle- this produces the point
1/4 in. from the edge for the seam allowance. Then fold it back and trim underneath again. It WILL produce a point that is 1/4 in. from the edge and you WILL have all your points. I promise!
Leslie, Missy & The Furbabies in MO.