How to Install Gutters
Slope is the whole job. Gutters need a fall of about 1/4 inch per 10 feet toward the downspout, which means a 40 foot run drops a full inch from the far end to the outlet. A run that looks level to the eye holds standing water, breeds mosquitoes, sags under the weight, and pulls its own hangers out of the fascia.
Everything else is straightforward: snap a chalk line at the correct fall, hang the gutter to that line with hidden hangers every 24 inches, cut and seal the corners, and drop a downspout at least every 35 to 40 feet. Get the line wrong and no amount of good hardware saves the installation.
Working on the roof edge anyway? Our roofing calculator sizes squares, bundles, and drip edge if the shingles are due at the same time.
Updated September 2026
A note on numbers. This page gives you dimensions, quantities and scope, not dollar figures. Material and contractor pricing varies by region, by season and by the specifics of your job, and we do not set any of it. Work out what you need here, then get quotes that can be compared to each other.
This guide covers installation. If your gutters are already up and just need clearing, our how to clean gutters guide covers the scoop and flush method, downspout clearing, and how often to do it.
How to install gutters, step by step
- Measure every run and count inside corners, outside corners, and end caps.
- Decide downspout locations first, because the slope runs toward them.
- Check the fascia for rot and repair it before anything hangs on it.
- Mark the high point about 1/2 inch below the roof plane at the far end of the run.
- Snap a chalk line to the low end, dropping 1/4 inch per 10 feet.
- Install the fascia brackets or hidden hangers to the line, into the rafter tails where possible.
- Cut the gutter sections, seal and rivet the seams, and set the end caps.
- Hang the gutter, then cut the downspout outlets.
- Assemble the downspouts with elbows and straps, one strap per 8 to 10 feet.
- Add extensions at the bottom and test the whole system with a hose.
A single story house with 120 to 150 linear feet of gutter is a full weekend for two people. Sectional aluminum from a home center is the DIY path. Seamless is a different conversation, covered below.
Ladder safety comes first
More people get hurt installing gutters than get hurt by gutters, and the ladder is why. Read this section even if you skim the rest.
Set the ladder at a 4 to 1 angle. One foot of base out from the wall for every 4 feet of height to the contact point. A gutter line 16 feet up puts the ladder feet 4 feet out. Too steep and the ladder tips backward the moment you lean out to hold a section. Too shallow and the feet skid. Quick check: stand with your toes touching the ladder feet and put your arms straight forward. Your palms should just land on the rung at shoulder height.
Never let the ladder rest on the gutter. This matters even more during installation, because the gutter you crush is one you just paid for. Use a ladder standoff or stabilizer, an inexpensive accessory that spans the load onto the roof edge or the wall and holds the top of the ladder 10 to 12 inches away. That clearance is also what lets you work in front of the gutter instead of around the ladder.
Three points of contact at all times. Two feet and a hand, or two hands and a foot. That means one hand for the gutter section and nothing in the other. A 10 foot section of aluminum gutter is light but it catches wind like a sail, so have a helper on the ground feeding it up rather than carrying it up a ladder.
Stay off the top three rungs of an extension ladder. Above that you lose your handhold and your hips go over the top of the ladder.
Keep your belt buckle between the rails. The instant your hips pass outside the side rails, the ladder wants to walk sideways. Climb down and move it. Moving a ladder fifteen times is boring, and reaching once is how people fall.
Look up before you set the ladder. The overhead service drop, the wires running from the utility pole to the house, usually terminates at a mast right where you want to work. Aluminum gutter is a 10 foot conductor and so is an aluminum ladder. Keep both far away from that drop. If the gutter run passes under or near the service entrance, that is a section to hire out.
Also: no wet ladders, no ladders on soft ground without a stable board underneath, and nothing at all on a windy day.
Gutter sizing: 5 inch or 6 inch
The residential default is 5 inch K-style aluminum with a 2x3 inch downspout. It handles most single family roofs in most climates, and it is what the entire home center supply chain is built around.
Go to 6 inch K-style with 3x4 inch downspouts when:
- The roof area draining to one run is large, roughly over 800 to 1,000 square feet.
- The roof is steep. A steep pitch throws water off the edge faster and it overshoots a narrow gutter.
- You are in a high rainfall intensity area, the Gulf Coast, Florida, the Pacific Northwest in winter storms.
- Long runs with few downspout locations, common on a long ranch.
The honest answer is that roof area and local rainfall intensity drive it, not the size of the house. A 6 inch gutter carries roughly 40 percent more water than a 5 inch, and a 3x4 downspout moves about twice the water of a 2x3. If you are borderline, the cheaper upgrade is usually adding a downspout rather than going to 6 inch gutter.
Half round gutter is the third common profile. It is period correct on older homes and it clogs less because there are no square corners, but it holds less water per inch of width than K-style and it costs more.
Our roofing calculator gives you the roof area per plane, which is the number the sizing decision actually depends on.
Gutter materials compared
| Material | Relative material cost | Lifespan | Where it fails |
|---|---|---|---|
| Vinyl | Cheapest of the six | 10 to 20 years | Gets brittle in UV and cold, sags between hangers, snaps under ice |
| Aluminum, .027 gauge | Slightly above vinyl | 20 to 30 years | Dents easily, ladder damage, thin gauge oil cans |
| Aluminum, .032 gauge | A small step up from .027 | 25 to 35 years | Same, but noticeably stiffer, worth the upgrade |
| Galvanized steel | Roughly double aluminum | 15 to 25 years | Rusts at seams and inside the trough once coating wears |
| Copper | The most expensive here, several times steel | 50 to 100 years | Cost, theft, and it needs soldered joints by a skilled installer |
| Zinc | Close behind copper | 50 plus years | Cost and availability, needs experienced install |
Aluminum is the practical answer for almost every house. Pay the small premium for .032 gauge over .027 if you get the choice, because the stiffer material resists dents from ladders and ice and hangs straighter between brackets.
Vinyl is the DIY temptation and it is fine for a shed, a small porch, or a mild climate. It is not fine in a place with real freeze and thaw. Vinyl loses impact strength as it gets cold, which is exactly when ice loads it.
Copper is beautiful and it is a specialty trade. Joints are soldered, not sealed, and a bad solder joint on copper is worse than no gutter at all. Hire it.
Sectional versus seamless
Sectional gutter comes in 10 foot lengths that you join with connectors and sealant. You can buy it at any home center, carry it in a pickup, and cut it with tin snips or a miter saw with a fine tooth blade. Every joint is a potential leak, and joints are where sectional gutters fail, usually 5 to 10 years in when the sealant lets go.
Seamless gutter is formed on site. A truck arrives with a roll former, feeds a coil of flat aluminum through it, and extrudes your run in one continuous piece to the exact length. No joints except at corners and outlets. It is the standard for professional installation and it is meaningfully better.
The catch is that the roll former is the whole business. The machine is a serious capital purchase, it lives on a trailer, and nobody rents it to homeowners. So "seamless" in practice means hiring a contractor. Installed seamless aluminum is roughly double what sectional material costs you if you hang it yourself, and the gap is labor, not metal.
Some regional suppliers will run seamless lengths for you to pick up and hang yourself. That is worth a phone call. You get the jointless run and you supply the labor, and the material alone is priced close to sectional stock.
Hangers, spacing, and the fascia problem
Hidden hangers are the current standard. They clip inside the gutter lip and screw through the back of the gutter into the fascia. They are stronger than the old spike and ferrule system, they do not show, and they do not work loose the way spikes do.
Spacing: 24 inches on center in most climates. 16 to 18 inches where you get snow and ice. Ice loading is enormous. A 5 inch gutter full of ice weighs roughly 10 to 15 pounds per foot, so a 30 foot run can carry 400 pounds. Hangers every 3 feet, which is what a rushed installer does, is how a gutter ends up hanging off the house in February.
Hit the rafter tails where you can. Fascia board is often 1x6 or 1x8 pine or a composite, and a screw into fascia alone is holding in about 3/4 inch of soft wood. Rafter tails are usually at 16 or 24 inches on center directly behind it, and a hanger screw that catches one is dramatically stronger.
Now the part people skip. Check the fascia before you hang anything. Press a screwdriver into the fascia every few feet, especially under old gutter seams and at corners. If it sinks in, the wood is rotten.
Gutters hung on rotten fascia will fail. That is not a caution, it is a certainty. The screw threads have nothing to hold, the weight of one wet season pulls them through, and you get to do the entire job twice, plus the water damage the sagging gutter caused in between.
Repair sequence when you find rot:
- Pull the old gutter and remove the fascia board in the affected section.
- Check the rafter tail ends behind it, because rot usually started there.
- Sister or cut back and splice any soft rafter tails. If several tails are gone, this becomes a structural repair and it is worth a carpenter.
- Check the soffit and the roof edge above. Rotten fascia almost always means water has been getting behind the gutter, which points at a missing drip edge.
- Replace the fascia with primed and painted material, primed on all six sides including the cut ends.
If the fascia rot extends into the roof sheathing at the eave, stop and get a roofer to look at it. That is a roof repair with a gutter symptom.
One more caution on older homes. Paint on fascia and trim from before 1978 may contain lead. Do not sand or power wash it dry. Use wet methods, a HEPA vacuum, and containment, or hire a lead certified contractor.
Downspout placement and how many you need
One downspout per 30 to 40 feet of gutter run, minimum. More is better and more is cheap. Every downspout you add shortens the distance water has to travel, reduces the depth in the trough, and lowers the load on the hangers.
Practical rules:
- Put downspouts at the ends of runs, at the corners of the house, where they are least visible.
- A run longer than 40 feet gets two downspouts, one at each end, with the high point in the middle. The gutter then slopes both directions from a center peak.
- Do not discharge one downspout onto a lower roof. That concentrates the flow of an entire upper roof onto a few shingles. If it is unavoidable, run a diverter or a pipe across the lower roof to its own gutter.
- Size the outlet to the downspout. A 2x3 outlet on a 3x4 downspout throttles the whole system at the hole.
Rough capacity check. A 2x3 downspout drains roughly 600 square feet of roof in typical rainfall. A 3x4 drains roughly 1,200. Take the roof area feeding each run, divide by that number, and round up. A 1,600 square foot roof split across four runs is 400 square feet per run, so one 2x3 per run is fine.
Drip edge, and why water gets behind gutters
Drip edge is the L shaped metal flashing at the roof edge, under the underlayment at the eave and over it at the rake. It sticks out past the fascia and kicks water forward into the gutter.
Without it, water leaving the shingle edge follows the underside of the shingle by surface tension, wraps around the roof edge, and runs down the back of the fascia. That is the water that rots fascia, soaks soffits, and drips inside the wall while the gutter itself looks perfectly clean.
If you are installing gutters on a house with no drip edge, this is the moment to add it. It is one of the cheapest parts of the job, and it goes on before the gutter. Slide it under the first course of shingles at the eave, nail it to the sheathing, and make sure the leading edge extends past the fascia and into the gutter trough, not behind it.
Check the gutter apron too, which is the wider version specifically made to bridge from under the shingles down into the gutter. On a roof where the fascia sits proud or the shingle overhang is short, a gutter apron solves what plain drip edge does not.
Getting water away from the foundation
Water in a gutter is only useful if it ends up far from the house. A downspout that dumps at the wall has simply concentrated the whole roof into one spot at the foundation, which is worse than no gutter at all.
- 4 to 6 feet minimum from the foundation for a downspout extension. 10 feet is better on clay soils.
- Slope the ground away from the house, aiming for about 6 inches of drop in the first 10 feet.
- Splash blocks are the cheap version and they work if the grade cooperates. Buried solid pipe to a daylight outlet or a dry well is the durable version.
- Do not use flexible corrugated pipe underground. The ridges catch sediment and it clogs. Solid smooth wall PVC at 4 inches with a proper slope stays clear.
This is directly connected to basement moisture. Most wet basements are surface water problems, not groundwater problems, and roof runoff at the wall is the single biggest source. If you are already dealing with the consequences, our cost to finish a basement guide covers what has to be fixed outside before any interior work is worth doing.
Worked example: a 1,600 square foot ranch
Here is a real layout so the numbers are concrete.
The house is 32 feet wide by 50 feet deep with a simple gable roof, so gutters run along the two 50 foot eaves. Total gutter: 100 linear feet. No inside corners.
Downspouts. Each 50 foot run is over the 40 foot rule, so each gets two downspouts, one at each end. Four total. The high point on each run sits at the center, at 25 feet, and slopes both directions.
Slope math. Each half run is 25 feet. At 1/4 inch per 10 feet, the drop is 25 / 10 x 0.25 = 0.625 inches, call it 5/8 inch. So the chalk line starts at the center high point and drops 5/8 inch over 25 feet in each direction. That is the number you snap, and it is small enough that eyeballing would have missed it entirely.
Hangers. 100 feet at 24 inch spacing is 50 hangers. In a snow region at 16 inch spacing it is 75. Buy 10 percent extra.
Sizing. Roof area is 32 x 50 = 1,600 square feet of footprint, split between two planes, so 800 square feet drains to each run. Split again by two downspouts per run, that is 400 square feet per downspout. A 5 inch gutter with 2x3 downspouts handles it comfortably in normal rainfall. In a high intensity rainfall region, upgrade the downspouts to 3x4 rather than the gutter to 6 inch.
Materials list:
| Item | Quantity | What to watch when you buy it |
|---|---|---|
| 5 inch K-style aluminum gutter, 10 ft sections | 10 sections | Gauge. The .032 stock is the single biggest share of the material bill and the one upgrade worth taking |
| Hidden hangers with screws | 55 | Screw length. The ones packaged with the hanger are often too short to reach a rafter tail |
| End caps | 4 | Left and right are different parts. Count both |
| Outlets and drop connectors | 4 | Match the outlet to the downspout size, not the gutter size |
| 2x3 downspout, 10 ft | 6 sections | Upsizing to 3x4 here is far cheaper than upsizing the gutter to 6 inch |
| Elbows | 12 | A and B elbows turn in different planes. Buying the wrong mix is the classic second trip |
| Downspout straps | 8 | One per 10 feet minimum, plus one at every elbow |
| Sealant, rivets, screws | 1 lot | Gutter sealant, not silicone. Silicone will not bond to the sealed run later |
| Drip edge, 10 ft pieces | 10 | Cheap, and skipping it undoes the whole job |
| Extensions or splash blocks | 4 | The last few feet of the system, and the part most likely to be left off |
Total the line items at your own supplier before you leave the house. The gutter stock and the hangers are the bulk of it, and everything else is small enough that buying spares costs less than a second trip.
What decides the cost, DIY or hired
Gutter quotes are built from linear feet, and then adjusted by a short list of things that have nothing to do with linear feet. This is what moves the number:
| Factor | Which way it pushes | Why |
|---|---|---|
| Material | Vinyl cheapest, then aluminum, then steel, then zinc and copper | Copper and zinc are also a specialty labor rate, not just a pricier metal |
| Sectional versus seamless | Seamless is the pricier install and the better one | You are paying for the roll former and the crew that owns it |
| Story height | The single largest multiplier on a labor quote | Ladder time, staging, and fall risk, not extra metal |
| Number of corners and outlets | Each one adds labor | Miters and outlet cuts are the slow part of any run |
| Roof pitch and overhang | Steeper and deeper both raise it | Both change how the ladder can be set and how far the installer reaches |
| Fascia condition | Rot turns a gutter job into a carpentry job | This is the line most often discovered mid job, so ask for it to be priced up front |
| Removal and disposal of old gutter | Usually a separate line | Confirm it is in the bid rather than assuming |
| Downspout count and where water goes | Extensions and buried drains are add-ons | The cheapest bid is often the one that dumps at the foundation |
| Gutter guards | An add-on, quoted per foot | Ask whether the warranty on the gutter still stands with a third party guard on it |
To get numbers you can compare, price two written local quotes on identical scope. Give both bidders the same linear footage, the same material and gauge, the same downspout count, and the same answer on fascia repair and old gutter removal, then compare line by line. A bid that comes in noticeably under the others is usually missing fascia repair, disposal, or the downspout extensions.
The DIY savings on a single story house are real, and on a 100 foot job they are a meaningful fraction of an installed price. On a two story house the savings shrink and the risk climbs, because the ladder work is the expensive part of the labor for a reason. That is the point where hiring it out usually makes sense.
If you are replacing siding or roofing at the same time, sequence matters. Roofing and drip edge go first, then gutters, then siding trim. Our roofing calculator and siding calculator will size those jobs so you can bundle the quotes.
Frequently asked questions
How much slope do gutters need?
About 1/4 inch of fall per 10 feet of run toward the downspout. Over a 40 foot run that is a 1 inch total drop, which is small enough to be invisible from the ground but is the difference between a gutter that drains and one that holds standing water. Some installers go slightly steeper, up to 1/2 inch per 10 feet, on runs where the extra drop will not look obvious.
Can I install gutters myself?
On a single story house with sound fascia, yes, if you are comfortable on a ladder and you have a helper. Sectional aluminum is designed for it. Two story work, seamless gutter, copper, and anything near the electrical service drop should go to a professional. Any run where the fascia is soft becomes a carpentry job before it is a gutter job.
How far apart should gutter hangers be?
24 inches on center in mild climates, and 16 to 18 inches where snow and ice load the gutter. Aim for the rafter tails behind the fascia when you can, since a screw into a rafter tail holds far better than one into a 3/4 inch fascia board alone. Closer spacing is cheap insurance and it keeps the gutter from developing waves between hangers.
What size gutters do I need, 5 inch or 6 inch?
5 inch K-style handles most residential roofs. Move to 6 inch when a single run drains more than about 800 to 1,000 square feet of roof, when the pitch is steep enough that water overshoots, or when you live somewhere with intense downpours. Often the better fix is an extra downspout or upgrading from 2x3 to 3x4 downspouts, which is cheaper than resizing the whole gutter.
How many downspouts do I need?
At least one per 30 to 40 feet of gutter run, and one at each end of any run longer than 40 feet. A downspout roughly every 30 feet is a good target. Adding downspouts is the cheapest way to improve a gutter system, because it reduces water depth in the trough, cuts the load on the hangers, and shortens the travel distance.
Do gutters go under the drip edge or over it?
The drip edge should extend past the fascia so its leading edge points down into the gutter trough, with the back of the gutter behind and below it. Water leaving the shingles hits the drip edge, breaks free, and falls into the gutter. If the drip edge stops short of the gutter or sits behind the back of it, water wraps around and runs down the fascia instead.
Can gutters be installed on rotten fascia?
No, and installing them anyway means doing the job twice. Screws have nothing to bite in soft wood, and the first heavy rain or ice load pulls them through. Probe the fascia with a screwdriver before you start, replace any board that gives, and check the rafter tails behind it, because rot generally starts at the tail ends.
How much does gutter installation cost?
It is quoted per linear foot, so start by measuring your eave runs. From there, four things set the number: the material and gauge, whether it is sectional or seamless, the story height, and how many corners, outlets, and downspouts the layout needs. Hanging sectional aluminum yourself on a single story house costs materials only and saves a meaningful share of an installed price. Seamless has to be hired, and two story work carries the largest surcharge on the bid because of ladder time. Get two written local quotes on identical scope, and make sure both of them price fascia repair, removal of the old gutter, and downspout extensions rather than leaving them to be discovered.
The short version
Snap the line first and hang to the line. A quarter inch per 10 feet toward the downspout, high point in the middle of any run over 40 feet, and a downspout every 30 to 40 feet.
Probe the fascia before anything hangs on it, because gutters on rotten wood fail without exception. Add drip edge if the roof does not have it, or water will run down the back of the fascia no matter how well the gutter drains.
Hidden hangers at 24 inches, or 16 in snow country, screwed into rafter tails where you can find them. Extensions carrying water 4 to 10 feet from the foundation. And set the ladder at 4 to 1 with a standoff so it never touches the gutter you just paid for.
Once the gutters are up, keeping them clear is the ongoing job, and our how to clean gutters guide covers that side of it.
