Step 1: Planning the rain gutter replacement project
Completed rain gutter
Almost all home centers and full-service hardware stores sell guttering that is designed primarily for easy installation. But with just a little bit more work, you can use these same parts to put together rain gutters and downspouts that are stronger and better looking too.
Evaluate and plan the gutter replacement project
Gutter replacement, which involves installing your own rain gutters can save you substantially over professionally installed gutters, but there are a few pitfalls to watch out for. Inspect the fascia and soffit (Fig. B) for signs of rotted wood, which will need to be replaced before you put up the rain gutters. Many houses have a trim board or crown molding nailed to the fascia just under the shingles. You’ll have to either remove this as we did or add a continuous strip of wood under it to create a flat plane for the gutters. In either case, prime and paint bare wood before you hang the gutters.
Draw a sketch and measure your house before installing house gutters
Fig. A shows an example of a rain gutter system for a typical house. Record the length of the rain gutter runs and mark the downspout locations. Then count up the inside and outside corners and end caps (note whether they are right or left ends). Measure the height of downspouts and add 4 ft. to each for the extension away from the house at the bottom. Each downspout requires three elbows. There are two types of elbows that turn either to the front or side of the downspout. Most installations require only front elbows, but occasionally you may need a side elbow, usually to turn the downspout extension sideways. Here are a few planning tips:
- Locate downspouts in unobstructed areas where water can be directed away from the house. Avoid locations with obstacles like electric meters, hose bibs or sidewalks.
- Place downspouts in inconspicuous locations if possible.
- Install oversized 3 x 4-in. downspouts on gutters that drain large roof areas or if you live in an area with torrential rains.
- Slope long gutter runs (40 ft. or more) down both directions from the middle and put a downspout on each end.
- Buy special roof hanger mounting straps for houses without fascia boards or for fascias that aren’t vertical.
Gutter Parts and Mounting Details
Measure the horizontal rain gutter runs and downspouts and identify the parts you’ll need.
Step 2: Cutting and joining the rain gutters
Photo 1: Cut the gutter
Cut the front and back sides with tin snips. Bend the gutter and cut the bottom.
Photo 2: Notch the gutter
Cut a 2-in. long notch in the front lip of the gutter with tin snips to join a rain gutter section with an inside or outside corner piece. (Cut a 4-in. long notch to overlap and splice together gutter sections.)
Photo 3: Snap the sections together
Lay a bead of gutter sealant along the corner 1-1/2 in. back from the edge. Hook the front lip of the corner over the notched section of gutter and snap it over the gutter.
Photo 4: Rivet the sections
Join the gutter to the corner with six rivets in the locations shown. Start by drilling a 1/8-in. hole (for 1/8-in. rivets) at the front of the gutter and installing the first rivet with the rivet gun. Now drill the remaining holes and install the rivets.
Photo 5: Caulk the seam
Caulk the seam on the inside of the rain gutter with gutter sealant. Put a dab of sealant over each rivet.
Preassemble before installing gutters
It’s much easier to join sections on the ground than to work from the top of a ladder. Photos 1 – 8 show how. Instead of butting parts together and covering the joints with a seam cover as recommended by the manufacturer, lap all seams from 2 to 4 in. Then caulk and rivet them together (Photos 3 – 5). We’ve shown joining a gutter section to a corner. Use the same process to join two sections of gutter, except overlap the pieces at least 4 in. When you’re splicing gutter sections, plan ahead to leave the best-looking factory-cut end on the outside if possible. Also, lap the rain gutters so the inside section is facing downhill to prevent water from being forced out the seam.
Where a gutter ends, cut it to extend about an inch past the end of the fascia board to catch water from the overhanging shingles. Then attach an end cap with rivets and seal the joint from the inside with gutter sealant.
Step 3: Adding downspouts and outlets
Photo 6: Mark the downspout outlet
Mark the center of the downspout outlet on the bottom of the gutter. Center the outlet, flange side down, over the mark and trace around the inside. Cut a V-shaped notch with an old chisel as a starting hole for the tin snips. Place two short scraps of 2×4 side by side under the gutter to support it while you chisel the notch.
Photo 7: Cut the outlet hole
Cut out the outlet hole with offset tin snips. Red tin snips cut counterclockwise. Green snips cut clockwise. Either one will work. Cut 1/16 in. outside the line.
Photo 8: Rivet the outlet in the hole
Slip the outlet into the hole and predrill 1/8-in. holes for the rivets. Remove the outlet and run a bead of gutter sealant around the opening. Press the outlet into the caulked opening and install the rivets.
Cut in downspout tubes at each downspout location
First measure from the corner of the house to the center of your chosen downspout location. Double-check for obstructions. Transfer this dimension to the gutter and cut in a downspout outlet (Photos 6 – 8). This method takes a few minutes longer than using one of the short gutter sections with a preinstalled outlet, but it eliminates two seams and looks much neater. You can make this cutout with a duckbill tin snips, but a special offset snips like we’re using (available from hardware stores and home centers) is much easier for beginners.
Step 4: Hanging gutter sections
Photo 9: Mark the gutter slope
When installing gutters, set the proper slope by driving a nail 1/2 in. below the shingles on the high side of the gutter run. Measure and record the distance from the bottom of the fascia board to this nail. Subtract 1/4 in. for every 10 ft. of gutter from this measurement and mark this distance at the low end of the gutter run. Drive a nail at this mark and stretch a chalk line between the two nails. Align a level with the string to check the slope. The bubble should be off-center toward the high side. If it’s not, adjust the string until the bubble indicates that you have the proper slope. Finally, snap the string to mark a line on the fascia board.
Photo 10: Screw the gutter to the fascia
Drive 1-1/4 in. stainless steel hex head sheet metal screws through the back of the gutter into the fascia. Install one screw every 2 ft.
A little slope is all you need
The number and size of downspouts determine how fast your gutters will empty. Sloping them helps eliminate standing water that can cause corrosion and leak through the seams. Slope each house gutters run down toward the downspout about 1/4 in. for every 10 ft. of gutter. If your fascia boards are level, you can use them as a reference for sloping the gutters. Check this by holding a level against the bottom edge. If they aren’t level, adjust the string line until a level aligned with it shows a slight slope (Photo 9). Snap a chalk line to indicate the top of the gutter. Then straighten gutter sections as you screw them to the fascia by aligning the top edge with the chalk line (Photo 10).
Step 5: Finish with flashing and hangers
Photo 11: Add gutter flashing
Slide gutter flashing under the shingles and secure with 1-in. roofing nails every 2 ft. Lap sections about 2 in.
Photo 12: Hook on gutter hanging straps
Hook a hanger under the front lip of the gutter and screw it through the flashing into the fascia. (The gutter apron will prevent you from slipping the hangers over the back edge of the gutter as intended.) Install hangers every 2 ft.
Flashing protects your fascia and soffit from water damage
With gutter replacement, you can prevent water from running behind your gutters by installing a metal gutter apron flashing under the shingles and over the back edge of the gutter (Photo 11). If your home center or hardware store doesn’t sell prebent flashing, ask an aluminum siding contractor or local sheet metal fabricator to bend some for you. Ideally the flashing should be slid under both the shingles and the roofing paper or ice and water barrier. If this isn’t possible because the ice and water barrier is stuck to the sheathing, or there are too many nails and staples along the edge of the roofing paper, then just slip the flashing under the shingles (Photo 11). If the flashing you’re using is too short to reach down over the back edge of the gutter, slip an additional strip of sheet metal flashing under the bent flashing and over the gutters.
Install hidden gutter hangers
With the gutters screwed to the fascia, it’s a simple job to install the hidden gutter hangers (Photo 12). Install hangers every 2 ft. to support the gutters and strengthen the front edge. The hangers are designed to slip over the back edge of the gutter, but since we’ve covered this edge with flashing, just hold them level and drive the screws through the flashing and gutter back into the fascia. The large screws included with the hangers we used are a little tricky to get started, especially through steel gutters and flashing. Spin them at high speed without applying much pressure until the screw tip bites into the metal. Then lean on the drill and drive them into the fascia.
Step 6: Installing the downspouts
Photo 13: Attach elbows to the downspout
Screw an elbow to the downspout outlet. Hold another elbow against the wall and measure between them. Allow for a 1-1/2 in. overlap at each end. Use a hacksaw to cut this length from the uncrimped end of a downspout tube.
Photo 14: Crimp one end of the downspout
Crimp one end of the short length of downspout with a special sheet metal crimper. With the three blades on the inside of the tube, hold the crimper against the inside corner of the tube and squeeze. Crimp three times across both long edges and twice on the narrow sides. Attach this short section of downspout to the two elbows with two 1/4-in. hex head sheet metal screws into each joint.
Photo 15: Fasten brackets to the wall
Cut strips about 1-1/4 in. wide from the end of a downspout with tin snips. Cut out a U-shaped bracket and snip off the corners. Measure from the corner of the house and mark the locations of each bracket, spacing them about 6 ft. apart. Attach the brackets to the house with stainless steel screws. (Drill a clearance hole through stucco with a masonry bit. Use plastic anchors for brick. Use 1/4-in.-long hex head screws for vinyl siding.) Cut and screw downspout sections to an elbow at the bottom. The bottom of the elbow should be about 6 in. above the ground. Slip this assembled downspout section over the crimped end of the top elbow and secure it with two screws.
Photo 16: Attach the downspout to the brackets
Drive screws through the brackets into the assembled downspout. Complete the assembly by adding a length of downspout tube to the bottom elbow to direct water away from the foundation.
A special crimper tool eliminates downspout frustration
Photos 13 – 16 show how to install the downspouts. We’re using standard 2 x 3-in. downspouts, but the procedure for oversized 3 x 4-in. ones is the same. Assemble the elbows and downspout tube with the crimped ends facing down to prevent water from leaking out of the joints. Use sheet metal screws rather than rivets so you can disassemble the downspouts to clean them if necessary. Pros prefer prepainted 1/4-in. hex head screws with very sharp points, called “zippers” because they’re easy to install. We found these screws in the aluminum siding section of a home center, but a gutter supplier would be another good source.
You can cut downspout tubing with a 32-tooth hacksaw blade, but the pro we talked to uses a circular saw with a standard 24-tooth carbide blade. A power miter box also works great for cutting both gutters and downspouts. Use an old blade, though. Protect yourself from flying bits of metal with goggles, leather gloves, jeans and a long-sleeve shirt.
Each length of gutter and every elbow is squeezed, or crimped, on one end to allow the pieces to fit together, one inside the other. Since 10-ft. lengths of downspout are only crimped on one end, you’ll have to crimp one end of any cutoff piece to make it fit inside the next elbow or downspout section. If you only have one or two downspouts to install, you can use a needle-nose pliers to twist crimps into the end. But an inexpensive crimping tool will save you tons of time and frustration (Photo 14).
Finish the gutter job by easier to hang the downspouts. attaching the downspouts to the wall. If you can’t find U-shaped brackets, make them from sections of downspout (Photo 15). They look better than the bands that wrap around the outside and make it easier to hang the downspouts.
After installing gutters, gutter maintenance is the key to long-lasting gutters
Clean leaves from your gutters twice a year, or hire a company that specializes in gutter cleaning and maintenance. You’ll extend the life of your gutters and eliminate problems like backed-up gutters and plugged downspouts.
Ten-foot lengths of metal gutters, downspouts and accessories are available at home centers, lumberyards and full-service hardware stores. Standard colors are brown and white. Matching inside and outside corners, downspout elbows and accessories are also available. Buy special gutter sealant to seal the seams. It’s available in small toothpaste-type tubes or 12-oz. caulk gun tubes.
Using many of the same basic techniques we show in this story, you can install your own “seamless” gutters. Listed under “Gutters” in the Yellow Pages, many seamless gutter companies will come to your house, measure and form continuous lengths of aluminum gutter to fit, and sell you all the installation accessories you’ll need. It costs a little more, but you’ll be able to choose from dozens of colors and eliminate seams in the gutter runs. You’ll also save the hassle of measuring, shopping and hauling the parts home in your VW bug.
Required Tools for this gutters and downspouts Project
Have the necessary tools for this DIY project lined up before you start—you’ll save time and frustration.
- Cordless drill
- Extension ladder
Required Materials for this gutters and downspouts Project
Avoid last-minute shopping trips by having all your materials ready ahead of time. Here’s a list.
- 1 1/4" self-tapping hex head screws
- 1/4" hex head screws ('zippers')
- 1/8-in. medium length rivets
- Gutter flashing
- Gutter hanging strap
- Gutter sealant