How to Adjust Gutter Slope in 6 Steps to Improve Drainage
Gutters that go with the flow
This project requires a lot of experience, so we don’t recommend DIYing it. Hire a pro with the special skills and tools necessary to complete the job safely.
- Tape measure
- Pencil
- Drill with screw bits
- Chalk line
- Ladder
Gutters are great inventions—as long as they’re working correctly. While most people focus on removing clogs, it’s important to pay attention to the angle or slope of the gutters, too. Learning how to adjust gutter slope ensures the water flows properly to the downspouts. When water doesn’t flow correctly, the gutters don’t dry properly, allowing mold to form and debris to rot.
As long as you’re comfortable climbing on and working from a ladder, adjusting the gutter slope is a doable, though challenging, DIY job.
Measure the Length of the Gutter
Photo: Lex20 / iStock / Getty ImagesMeasure the length of the section of gutter that needs adjustment. This can be difficult to do without two people on separate ladders. However, you don’t need an exact measurement in this step. You can also take an approximate length measurement while standing on the ground and estimating the starting and ending points.
Determine the Current Slope
If you made an estimated measurement and did not climb a ladder in the previous step, unfortunately, you can’t avoid it in this step. You need a precise measurement here.
Start at the end of the gutter farthest from the downspout. Climb the ladder and measure the distance from the edge of the roof to the top of the gutter. Repeat this measurement at the end closest to the downspout.
You can now calculate the slope. How much slope does a gutter need? For every 10 feet of gutter length, the end away from the downspout should be about 1/4 of an inch higher than the end closest to the downspout. If you have a 25-foot section of gutter, the far end should be 5/8 of an inch higher than the end near the downspout.
If your current gutter doesn’t have enough slope, you’ll need to take it down and readjust it. If it has the correct slope on each end, take a few more measurements to be certain the gutter isn’t sagging in the middle, causing water to collect.
Detach the Gutter Brackets
Photo: Lex20 / iStock / Getty ImagesTo fix the overall slope or a sagging gutter section, disconnect the entire gutter from the fascia board by removing the bracket screws. You can temporarily tack the gutter lower on the board to keep it from falling to the ground. You may have to detach part of the downspout to create space to work.
This step will be slow-going, as you’ll have to move the ladder multiple times.
If you notice any problems with the integrity of the fascia, consider repairing or replacing the fascia board during this process.
Snap a Chalk Line
Using a pencil, mark the desired distance of the top of the gutter from the edge of the roof on the fascia board. Make the proper mark on both ends, taking the slope into account.
Tack the chalk line on one end and stretch it tightly to the far end. Snap it to create the line the top of the gutter should follow along the fascia. If your section of gutter is lengthy, you may need someone else to climb a second ladder and snap the middle of the line.
Attach the Gutter Along the Chalk Line
Use the screws to reattach the gutter brackets, ensuring the top of the gutter is precisely following the chalk line. Again, this step will take a while because you’ll have to move the ladder quite a few times.
Test the Water Flow
Once the gutter is tightly attached again, test the slope you’ve created. Place a garden hose in the gutter at the end farthest from the downspout. Turn the water on at a low flow rate and watch how it moves through the gutter toward the downspout. It should flow smoothly and quickly.
If the water starts collecting or doesn’t flow steadily, the slope measurement is likely still wrong. Double-check your measurements or seek help from a gutter professional.
When to Adjust Gutter Slope
You should take steps to adjust the gutter slope any time you notice water collecting in the gutters instead of flowing to the downspouts.
When professionals initially installed your gutters, they determined how to adjust the gutter pitch for proper water flow. Learning how to design a gutter system requires ensuring the gutters have the desired slope and pitch.
However, a few years after installation, the gutters may begin to sag, affecting the slope. You may then need to take steps to adjust the gutter pitch.
DIY vs. Hiring a Pro
Although you don’t have any costs associated with adjusting the gutter pitch yourself, you will have to invest at least a couple of hours. You’ll need to go up and down the ladder multiple times. If you don’t feel comfortable standing on a ladder and using a power drill, you should enlist the help of a pro.
Adjusting gutter slope is similar to DIY gutter installation. If you wouldn’t tackle installing your own gutters, you shouldn’t try adjusting gutter slope yourself.
A professional can tell you if there are signs you need new gutters. Perhaps your gutters are too worn to adjust the slope properly. If the fascia board is rotted, it won’t hold the gutters in place, causing sagging.
A local gutter installation company can adjust the slope of your existing gutters and make any necessary repairs.
Frequently Asked Questions
The gutter gauge is a measurement of the thickness of the gutter material. If you have gutters that are too thick and heavy for the screws and brackets holding them in place, they may sag. Materials that are too thin could suffer damage that leads to sagging. A professional gutter installer can ensure you have the right gutter gauge.
If you don’t have the right gutter sizes installed, the water may not flow properly. Small gutters need a sharper slope to move the water faster before it can overflow. Larger gutters can hold more water if you must use a shallow slope on the length of the gutter. A gutter installer can provide advice on the right gutter size.
Gutters should not drip at the seams. This problem could indicate that water is collecting in the gutters instead of moving to the downspouts. You could have leaves or other debris blocking the flow of water at the seams. Try cleaning the gutters, adjusting the slope, and sealing any holes or cracks in the material to fix this problem.
