What should the slope of a gutter be?

Dick in Wisconsin · Oct 15, 2013

We have a section gutter on our house about 25 or 30' long. A valley drains into it, so it gets lots of water during a heavy rain. Its in front of the kitchen window so when it rains hard its easy to see when it overflows.

After the rain I got the ladder out. There were lots of leaves in the gutter, some in the downspout.

I've never liked the self tapping sheet metal screw at the top of the downspout; grabs the leaves and holds them. So I replaced it with a small button head bolt. Now there is NO dager to catch and hold the leaves.

I got the hose out and washed the leaves towards the downspout, but I realized it was an uphill battled! When I got all the leaves cleaned out, I realized that the gutter drained away from the downspout.

So ... I think I'm going to try to reset the slope of the gutter. What is "normal"? Should I be able to easily reset the slope, actually in the opposite direction?

What do you guys think?

jshillin · Oct 15, 2013

As long as you make it flow downhill you will be fine. The slope doesn't have to be anything crazy, just make sure it goes down over the entire distance of the gutter. As for fixing yours, it depends on how far out it is. If it's just a little out you may be able to remove all of the screws except for the middle one with someone else's help and then change the angle and drive the gutter hanging screws back in. If it's really bad, you might have to pull it down and then just hang it back up correctly.

CharlestonJoe · Oct 15, 2013

It shouldn't be to difficult to correct.
When you noticed the water flowed the wrong way, how deep did it get?
For example; if the gutter was holding an inch of water, then raise it at least an inch, or lower the other end, but readjusting the downspout end will obviously be more of a hassle..
Sometimes you can just take pliers and twist the gutter strap a little and get the gutter to raise enough.

ts3342 · Oct 15, 2013

Most people around here make the gutter level because if the gutter is 4 inches tall that will give you a 4 inch drop.

Scott H in Wheaton · Oct 15, 2013

1/2 inch for every 10 feet of run.

On your 25-30 ft gutter you should be 1 1/2 inch lower by the time you get to the downspout.

If your gutter hangers are strapped thru the roof you may have to cut them to get them out of the way.
If you have the old fashioned spike-and-tube hanger they have probably loosened up over time.
You need hidden hangers that go inside the gutter and attach with screws, not those stupid twisted nails that back out after a few years.

WQ59B · Oct 15, 2013

IMO, long gutter runs should dump into 3x4" downspouts rather than 2x3". I have one gutter run of about 60 feet, and changing each end to 3x4"ers has really made a big difference. I also prefer rivets to self-tappers.

BADSIX · Oct 15, 2013

it should be level, nobody wants a gutter sloped to one end. think about how that would look and what if we were doing 40 ,50 or 60 ft.. You'd have to have a 12" fascia board
Jay D

mmhouse · Oct 15, 2013

BADSIX said:
it should be level, nobody wants a gutter sloped to one end. think about how that would look and what if we were doing 40 ,50 or 60 ft.. You'd have to have a 12" fascia board
Jay D

I had a level gutter on one side of my house. It would run over in heavy downpours and eventually caused my paver patio to sink in a couple of areas (now fixed).

I recommend at least some slope on the gutter. It doesn't have to be a lot, as others have said, but needs to be there. And it doesn't look bad - most people would never notice.

tornadocaster · Oct 15, 2013

We manufacture these products and sell to the installers. Everything mentioned is correct and when i do my personal projects I use rivets. But the first thing younshouod change are the outlets. When we took over the company here 8 years ago the first thing we did is get rid of the plastic round outlets with the built on cage. The biggest reason is they crack in our extreme weather here and they plug real easy.
The most common outlet now is the round 2-1/2" aluminum one because it goes in easy but the simple upgrade is the rectangular or square that's the same size as the pipe so you take advantage of its full flow capacity. If memory serves me right a 2x3 pipe flows 85 gallons per minute. Also if you have the spike and ferrule hanger system and they're loose maybe replace them with long 7" screws instead and find fresh wood. You can also supplement with hangers if you feel the need.
Cheers
Gio

BADSIX · Oct 15, 2013

mmhouse said:
I had a level gutter on one side of my house. It would run over in heavy downpours and eventually caused my paver patio to sink in a couple of areas (now fixed).

I recommend at least some slope on the gutter. It doesn't have to be a lot, as others have said, but needs to be there. And it doesn't look bad - most people would never notice.

If your gutters are level and you have water running over them, then they are not designed properly with enough down spouts or they are partly plug. If they are sloped to one end then all the water hast to go down one down spout. if you install them level water will drain at both ends twice the volume.
Jay D

shannonw · Oct 15, 2013

I'd reslope it. My house 1/2 the gutters were installed level. Florida rain was nuts, dang things never worked right. everything overflowed or water sat in the middle for weeks . Finally i asked myself why the heck would you make a gutter level...makes no sense, so i called a gutter guy in. But we get a TON of rain in minutes, not sloping here isn't going to work when a monsoon is pouring down.

You don't want that especially if you have joints (not rolled on site).

Anyways, long story had everything resloped, and made sure they sloped the new ones. zero problems after that.

I have some long runs, what scott H says is probably about right just from what i recall eye balling mine.

Scott H in Wheaton · Oct 15, 2013

Yeah, leave them level if you prefer to have them hold water and become a breeding ground for mosquitos and if you want leaves to rot and turn into compost.

Water that doesn't slope towards a drain is called a puddle.

By the way, I sold and installed about 200 gutter jobs in the last nine years, but what do I know.

2x3 downspout gets maxed out with about 30 ft of gutter spilling into it. 35-50 ft you need bigger 3x4 downspout or two of the smaller ones.

On a 60 ft gutter the high spot is in the center and the gutter will slope towards a downspout at each end.

pattenp · Oct 15, 2013

I know a couple professional gutter installers and they install with a slope of 1/4" per 10'. Long runs with down spouts at both ends are sloped from the center.

BADSIX said:
it should be level, nobody wants a gutter sloped to one end. think about how that would look and what if we were doing 40 ,50 or 60 ft.. You'd have to have a 12" fascia board
Jay D

shannonw · Oct 15, 2013

yeah after resloping mine, they stayed A LOT cleaner. Before.. exactly like scott says, mulch mess and mosquito breeding ground.

steve911 · Oct 16, 2013

Scott H in Wheaton said:
Yeah, leave them level if you prefer to have them hold water and become a breeding ground for mosquitos and if you want leaves to rot and turn into compost.

Water that doesn't slope towards a drain is called a puddle.

By the way, I sold and installed about 200 gutter jobs in the last nine years, but what do I know.

2x3 downspout gets maxed out with about 30 ft of gutter spilling into it. 35-50 ft you need bigger 3x4 downspout or two of the smaller ones.

On a 60 ft gutter the high spot is in the center and the gutter will slope towards a downspout at each end.

On sort of the same note as what we are talking about, I live in the midwest and need to put gutters onto my shed that I built.

The run will be 50 ft long on each side with a down spout on the ends. The height of the facia is only 7 1/2 ft off of the ground.

What should I expect to pay for one of those seamless gutter companies to install the gutters. Color is white.

Tucko · Oct 16, 2013

An eight of an inch for every 10' of run is what I've always done. Some torpedo levels will have notations for 1/8" slope and 1/4" slope.

Kevin54 · Oct 16, 2013

BADSIX said:
it should be level, nobody wants a gutter sloped to one end. think about how that would look and what if we were doing 40 ,50 or 60 ft.. You'd have to have a 12" fascia board
Jay D

A gutter NEVER goes level. It has to have fall to it. even if it only 1/2" to an 1" over 60', as long as it is hung straight meaning no bow in it, the water will run out. The more fall you can put in it though determines how fast the water runs out. The gutters can be bowed on a long run and have downs at each end.

But running a gutter truly level, the odd are of water laying in the gutter is greater than running a fall on the gutter.

NUTTSGT · Oct 16, 2013

**** in Wisconsin said:
What do you guys think?

****, I would put som eslope in the gutter. How much ? Depends on the length and size of you fascia. I'd also use these hangers too.

http://www.homedepot.com/p/Amerimax...85356?N=c5qr?browsestoreoption=1#.Ul7MLNLrzX8

Kevin54 · Oct 16, 2013

NUTTSGT said:
****, I would put som eslope in the gutter. How much ? Depends on the length and size of you fascia. I'd also use these hangers too.

http://www.homedepot.com/p/Amerimax...85356?N=c5qr?browsestoreoption=1#.Ul7MLNLrzX8

Those are the style that I have on our gutters. I didn't hang them but had a gutter guy hang all of ours with seamless. With that style of hanger, you never have to worry about them pulling out. He also runs a heavier gage of gutter, so if you toss a ladder up against it, the gutter will not dent or bow.

I remember back in the day that my dad didn't want to spend money on someone else doing the gutters. :eyecrazy:

For the money, you can't beat someone coming in and doing it and done in no time. My dad and I would spend a few days snapping lines to get a fall to the gutters, putting them together, cutting in the downs........... :puke:

And if you read the replies about the gutter hangers, overlook this guy.....

This would be a great hanger if it weren't for the fact that the screw will penetrate the gutter "below the water line", meaning if the gutter were to fill to capacity the screw hole would be under water, and there is no easy way to permanently seal the hole. Over a period of time the leakage can damage and weaken the fascia board and may cause the gutters to fall off. The bright side is it's better than a spike.
Pros: Easy to Work With
Cons: Leaks

If his gutters are filling full and leaking, then rotting the fascia and falling off, he has a little more of a problem than a $1.59 hanger :lol:

kbs2244 · Oct 16, 2013

I have a 40 foot level run with no problems.
But it isn't the lenghth of the gutter as much as it is the square footage being drained.

From your discription I would re-level the gutter, put in a water deverter at the foot of the valley to aim the water in the direction of the downspout.
(I would bet that the gutter is not overflowing but that the water now is coming with enough speed that it is just jumping over the gutter.)

Then go oversize on the downspouts.

Scott H in Wheaton · Oct 16, 2013

steve911 said:
On sort of the same note as what we are talking about, I live in the midwest and need to put gutters onto my shed that I built.

The run will be 50 ft long on each side with a down spout on the ends. The height of the facia is only 7 1/2 ft off of the ground.

What should I expect to pay for one of those seamless gutter companies to install the gutters. Color is white.

Leaf Guard will probably quote you $4000 but would do it for around $2500-3000.
Big Orange box would be $1620
Independants would be all over the board from $800 - $2000

Based on 100 ft gutter and 4 downspouts to do both sides.

ilovevocs · Nov 4, 2013

Capillary action will allow a level and unobstructed gutter to drain efficiently.

Sent from my iPhone using Tapatalk

ilovevocs · Nov 4, 2013

Scott H in Wheaton said:
Leaf Guard will probably quote you $4000 but would do it for around $2500-3000.
Big Orange box would be $1620
Independants would be all over the board from $800 - $2000

Based on 100 ft gutter and 4 downspouts to do both sides.

Gutter market in my area is in the toilet. In my area most residential guys are working for wages right now.

Sent from my iPhone using Tapatalk

tinbender 66 · Nov 5, 2013

ilovevocs said:
Capillary action will allow a level and unobstructed gutter to drain efficiently.

Sent from my iPhone using Tapatalk

Very true. I've done commercial architectural sheet metal for a couple decades and we ALWAYS hang them level as they are hung from the eave flashing and are free floating for expansion etc. Keep the leaves cleaned up and they will drain properly if you have enough downspouts for the roof area being drained.

ZRX61 · Nov 5, 2013

When I've installed them in the UK the standard was 1/4in in 12ft.

fastjohnny · Nov 7, 2013

Scott H in Wheaton said:
Leaf Guard will probably quote you $4000 but would do it for around $2500-3000.
Big Orange box would be $1620
Independants would be all over the board from $800 - $2000

Based on 100 ft gutter and 4 downspouts to do both sides.

My market would not support this at all. $500 or even less.

ybnormal70 · Nov 7, 2013

I just had 154' of 6" seamless gutter installed with 4 3"x4"x12' downspouts for a whopping $729. I had 3 estimates and I had one that was cheaper but I liked this guy the best. He did a great job.

L8r,

Kevin

Strouty · Nov 7, 2013

For the guys that say level gutters, doesn't it take more water to move it to the downspout or do you have them on both ends? Isn't there a gutter that has built in slope but the exterior is perfectly level? I have seen those for the drains you install in concrete.

Kevin54 · Nov 7, 2013

Strouty said:
For the guys that say level gutters, doesn't it take more water to move it to the downspout or do you have them on both ends? Isn't there a gutter that has built in slope but the exterior is perfectly level? I have seen those for the drains you install in concrete.

If a gutter is hung level, it will drain. But the chances of having a low spot in it is greater. You want to have some fall in a gutter so water will not stand.

And for the ones that say run it level I'm calling B.S. Around here you can have a rain or freezing rain. If that gutter is level, then you are going to have ice buildup. And on a long run, you want the gutters bowed from the center down and have gutters at both ends. With a slight fall you can diredt the water to go where you want.

cburnscrx · Nov 7, 2013

Scott H in Wheaton said:
1/2 inch for every 10 feet of run.

On your 25-30 ft gutter you should be 1 1/2 inch lower by the time you get to the downspout.

If your gutter hangers are strapped thru the roof you may have to cut them to get them out of the way.
If you have the old fashioned spike-and-tube hanger they have probably loosened up over time.
You need hidden hangers that go inside the gutter and attach with screws, not those stupid twisted nails that back out after a few years.

This! Exactly this. I researched before I did/am doing my gutters now. If you have those stupid spike ferules, dump them and get the hidden hangers. MUCH better.

cburnscrx · Nov 7, 2013

Scott H in Wheaton said:
Leaf Guard will probably quote you $4000 but would do it for around $2500-3000.
Big Orange box would be $1620
Independants would be all over the board from $800 - $2000

Based on 100 ft gutter and 4 downspouts to do both sides.

Well...

I just did my own, and I went to Reese Wholesale...I think I paid $2.29 or 2.59 a foot...rolled to any length. I got 25' gutters, used an extension ladder on top of the Suburban to support them, and drove them home. Not sure how you'd do driving with a 50' gutter though? Seamless to length gutters with MUCH less cost. The hangers were .59 and I can't remember the end caps or downspout cost. That was for 5" gutters with 4x3 downspouts.

DenisG · Nov 7, 2013

**** in Wisconsin said:
We have a section gutter on our house about 25 or 30' long. A valley drains into it, so it gets lots of water during a heavy rain. Its in front of the kitchen window so when it rains hard its easy to see when it overflows.

After the rain I got the ladder out. There were lots of leaves in the gutter, some in the downspout.

I've never liked the self tapping sheet metal screw at the top of the downspout; grabs the leaves and holds them. So I replaced it with a small button head bolt. Now there is NO dager to catch and hold the leaves.

I got the hose out and washed the leaves towards the downspout, but I realized it was an uphill battled! When I got all the leaves cleaned out, I realized that the gutter drained away from the downspout.

So ... I think I'm going to try to reset the slope of the gutter. What is "normal"? Should I be able to easily reset the slope, actually in the opposite direction?

What do you guys think?

This reference says 1/2" per 10 ft run: http://www.thisoldhouse.com/toh/how-to/overview/0,,442134,00.html

Personally, I try and get the maximum amount of slope possible. That's what I did when I fixed the gutters on my old house in Mass.

coolreed · Nov 7, 2013

A gutter does not have to slope very much. 1 degree will work. That downspout will have to always be clear since the run is so long. You might think about ways to keep leave out of it and/or increase the size of the downspout.

Good Luck.

John in OH · Nov 7, 2013

Typically, 1/16" per foot. So, a 40' gutter would have 2-1/2" of fall.

Gotta agree with Kevin, level is BS. If you've ever had to deal with ice & snow buildup ya know level won't work.

Kevin54 · Nov 7, 2013

DenisG said:
This reference says 1/2" per 10 ft run: http://www.thisoldhouse.com/toh/how-to/overview/0,,442134,00.html

Personally, I try and get the maximum amount of slope possible. That's what I did when I fixed the gutters on my old house in Mass.

coolreed said:
A gutter does not have to slope very much. 1 degree will work. That downspout will have to always be clear since the run is so long. You might think about ways to keep leave out of it and/or increase the size of the downspout.

Good Luck.

@ 1 degree, a 30' run would drop 6 1/4".

Using a 1/2" per 10', for a 30' run you're looking at a 1 1/2" drop.

As far as cut is stone rules go, a lot of things depend on the style of the home, the length of the run, the width of your fascia, then of course, wher you can put the downs.

A downspout DOES NOT have to be on an end. Depending on the style of the home and the roof lines, you can out downs in the center if you so desire and slope to the center from the ends. My garage gutters are 44' long and done in one run with downs on one end only. I may have 1"- 1 1/2" drop in that distance. The gutters that were done previously.....the installer just slapped them up, eyeballed a slope, and called it a day. I had just as much dripping from behind when it rained as there was going to the downs. Last year I had a guy come and redo my garage and a portion of the house. The house was an "L" shaped gutter. From the corner, it drained two different directions to the ends of the "L".

You have to keep in consideration your drip edge which your gutter should go up under where you can. If one follows some of the remarks as far as drop, by the time you get to the other end, you may have to install flashing from under the drip edge, and down into the gutter. You also want to consider surface area of your roof. If you have a real long run with a considerable slope, you may have to step up to a wider gutter. If you get a heavy rain and your gutters are overflowing, either they are plugged, they may not have enough slope, or they may not have enough downs. And one also has to realize that you want to get the water away from the house. And overflowing gutter can be a source of leaks in crawlspaces or basements. I think I mentioned above to, about ice dams building up when the weather changes.

So always remember to add some fall

Consider your drip edge and get the gutter under it as much as possible

Consider more downs, either add one at the other end if you don't presently have one, or if feasible, add one to the center

Rod N · Nov 7, 2013

Still laughing about the no slope. So no need to slope the roof either?
Anyway, having too much of an overhang on your shingles can result in water shooting right over the gutters as well and it's a ***** getting the leaves out.
This is the problem I'm having.

dreamingmuscle · Nov 8, 2013

Rod N said:
Still laughing about the no slope. So no need to slope the roof either?
Anyway, having too much of an overhang on your shingles can result in water shooting right over the gutters as well and it's a ***** getting the leaves out.
This is the problem I'm having.

You don't need any slope if your perfect. But who in this world is perfect?

There's always going to be a low spot if you try to make it level so why even try?

Scott H has said it best. Some slope, not much, larger down spouts or two down spots if your house permits it.

Glen

What should the slope of a gutter be?

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