Step 1: Evaluate your home and plan the project
Almost all home centers and full-service hardware stores sell gutter systems that are designed primarily for easy installation. But with just a little bit more work, you can use these same parts to put together gutters and downspouts that are stronger and better looking too. We'll show you how to minimize joints; assemble strong, sleek-looking seams; and add roof flashing to keep water flowing into the gutters where it belongs, all with off-the-shelf metal gutter parts.
If you're comfortable with basic hand tools, assembling and installing gutters shouldn't present any great challenge, but the job isn't for everyone. It requires that you know how to safely work from ladders (good balance and staying within your reach) and are comfortable doing it. Rent scaffolding for second-floor gutter work because it's much more stable than a ladder.
Installing your own gutters can save you as much as $5 per linear foot over professionally installed gutters, but there are a few pitfalls to watch out for. Inspect the fascia and soffit (Figure B) for signs of rotted wood, which will need to be replaced before you put up the 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.
Step 2: Measure your house and draw a sketch
Figure A shows an example of a gutter system for a typical house. Record the length of the 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.
Figure A: Gutter Parts
Your measurements and sketch will help you determine which parts you need. All the parts you need are widely available.
Step 3: Cut and assemble long sections
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 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 4: Cut in downspouts
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 (from hardware stores and home centers) is much easier for beginners.
Tip: Place two short scraps of 2x4 side by side under the gutter to support it while you chisel the notch (Photo 6).
Step 5: Hang the gutter sections
Photo 9: Set the slope
Set a 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. Finally, snap the string to mark a line on the fascia.
The number and size of downspouts determines how fast your gutters will empty. Sloping them helps eliminate standing water that can cause corrosion and leak through the seams. Slope each gutter 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).
Figure B: Mounting Details
First install the gutter at the slope set by the chalk line. Then add the roof apron to protect the fascia board and finally the gutter hangers.
Step 6: Install the gutter apron and hangers
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 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 7: Install the downspouts
Photo 14: Crimp cut ends
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: Make and mount brackets
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 building 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 siding 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 downspout section over the crimped end of the top elbow and secure it with two screws.
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 a crimping tool will save you tons of time and frustration (Photo 14).
Finish the gutter job by 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.
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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. Complete gutter systems cost about $2 per linear foot.
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 or online, 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. At about $3.50 per linear foot, 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.