There are at least three alternative ways to do it.
How to attach gutters to vinyl siding.
Hang gutters on vinyl siding in 9 steps.
Fasten the downspout to the gutter elbow with sheet metal screws according to the manufacturer s instructions.
At the furthest distance from the downspout measure inch down from the eaves of the house and mark this point.
Use screws with a fully threaded shank.
At the downspout.
Step 2 place a downspout strap at the top where it meets the elbow.
Check both ends of the siding for play first.
This renders the siding vulnerable to moisture and voids the warranty even if you seal the hole.
Inspect your gutters and look for an area where a downspout would not be obstructed on its way from the gutter to the ground near the roof.
You re only going into plywood.
This is the method used by all.
Affixed in the middle with room on both sides it should be fine.
Mount the bracket high up tucked under a lap so you don t buckle the siding while installing it.
The common practice of attaching downspouts to vinyl siding is to wrap a metal or plastic strap around the downspout and nail or screw through the vinyl siding.
Hold the downspout connector up against the bottom of the gutter and center it.
The gutters themselves will attach to these outlets so it s important to place them first to use as a guide as you continue installing.
Trace around the downspout.
Secure one end of the strap to the siding with a zip screw and a cordless screwdriver with 1 4 inch socket attachment.
How to fasten a downspout to vinyl siding.