Hanging a Rain Gutter, Downspout and Rain Barrel Step by Step

A gutter run of 26 feet, cut from a single piece of 24 gauge aluminum, is the centerpiece of this installation by This Old House general contractor Tom Silva. The question behind the job is how to hang a gutter so it drains properly and survives winter.

Why the house needs one

Without a gutter, rain coming off the roof hits the ground and splashes up, which could damage the siding, the trim and even rot the sill. If there is a basement, water could enter it. The homeowner in this job adds that in winter she gets drenched while looking for her keys at a spot with a lot of roof above it.

Getting the gutter

Tom orders the gutter from a local supplier whose truck carries a coil and a machine. He gives them a length and they run it out. The tape showed 25 ft 11 in., and he went with 26 ft. The gutter comes with left and right end caps.

Height and pitch

The mistake most people make is hanging the gutter too high. A level held out from the roof represents an imaginary line coming off the roof. If the front edge of the gutter reaches that line, it is too high. Hung lower, ice that slides off the roof will not hit the front edge and knock the gutter off.

Tom marks the high side and puts in a nail, attaches a chalk line, and positions the other end lower so water runs that way. He lines a level up with the line, checks the bubble to confirm there is a pitch, and snaps the line.

Preparing the gutter

Sealant goes into the end cap, which is pushed on and then squeezed with a crimping tool. The crimp makes a small divot so the cap will not come off. He makes the first cut with a hacksaw and finishes it with snips. The outlet hole is cut with a chisel, an old beat-up one, and a bead of sealant goes around the underside of the outlet before it is screwed in place.

Hanging it

The gutter is first screwed up temporarily about 2 in. lower than its final position. The hangers lock into the front of the gutter and go under the back, with a wood screw into the end of the rafter. Because of the bracket length, they could not be hooked on and bent down without hitting the roof. With the gutter lowered, Tom puts a bracket at every rafter, then repositions the gutter on the line and screws the brackets off. Keeping it low also let him see the nail heads of the fascia board that were in the rafter tails.

Downspout and rain barrel

The downspout starts at the top with two elbows. Partway down, the pipe is interrupted for a diverter with a screen inside, so the water fills the barrel and no leaves go in. When the barrel is full, overflow goes down the pipe and exits away from the building. The barrel sits on two concrete pavers to keep it level.

Tom's rule of thumb is a minimum of two outlets for a gutter 60 feet or longer. He says that on a small roof of 100 square feet, a 1 in. rainstorm will fill a rain barrel. In a cold climate, the barrel is disconnected from the diverter and flipped over for the winter.