Step 1
Dimensions Required:
Width of Verandah - wall to outside face of fascia beam (X)
Height - top of fascia beam to underside of verandah sheet (Y)
Plot these lines to scale on graph paper.

Step 2
Draw the straight section of sheet (A) at the required fall.
Note: Corrugated iron is not recommended for a pitch of less than 5 degrees.

Step 3
Determine the radius of curvature.
Note: The recommended minimum radius for CGI curving is 450mm. Stratco takes no responsibility for deformation that may occur from smaller radii.

Step 4
Set a compass to the radius of curvature and scribe arcs from both ends of line (A). Connect arc tangents to form parallel line (B). Set the compass point to the top front corner of the fascia Beam (C) and scribe an arc to intersect line B. From this intersection (D) set the compass point and scribe an arc from line (A) to a point 50mm past the fascia (E).

• Extend a perpendicular line from point (D) to intersect line (A)
• Draw a line from point (D) to point (E)
• Measure the resulting angle (F°)
• Measure the length of straight sheet
• Calculate the length of curvature using the following formula:

• Add the length of straight sheet to the curve length to determinethe total sheet length

Step 1
Dimensions Required:
Width of Verandah - wall to outside face of fascia beam (X)
Height - top of fascia beam to underside of verandah sheet (Y)
Plot these lines to scale on graph paper.

Step2
Draw a straight line (A) between the wall and fascia beam as shown in Figure 3 (overleaf). Locate the mid-point of line (A) and plot a perpendicular line (B) from this point. Determine the required dip and plot the point of intersection (C) on line (B).

Step 3
Using a flexible scale ruler, join the top and bottom of line (A) through point (C). Read the required sheet length from the scale ruler, allowing an additional 50mm past the fascia. If required, adjust the dip to effectively suit the fall into gutter.
Note: A minimum dip of 50mm is recommended for aesthetic reasons.

For convex verandahs repeat Step 1 to 3, however, plot intersection point (C) on the opposite side of line (A) at the required convex rise, refer to Figure 4.