A sagging gutter is almost always one of three things: the hangers are too far apart, the fasteners have worked loose, or the fascia behind them has gone soft. Work out which one you have before you buy anything, because the fix is different in each case and only one of them is solved by adding hardware.
Step 1 — Find out why it dropped
Get up and look at the low point. You are checking three things, in this order.
Is the fascia sound?
Push a screwdriver into the fascia board near the sag, just below the shingle line. If it goes in easily, or the wood is dark and spongy, the board is rotted and that is your answer. Stop here. No hanger holds in rotted wood. The board has to come off and be replaced before anything else you do is worth doing, and a gutter that has been dumping water down the fascia for a season or two is exactly how the rot got there.
Are the fasteners backing out?
If the run is hung on spikes, look along the front face. Spike heads standing proud of the gutter are the classic sign. Spikes are smooth nails held by friction, and seasonal movement in the fascia works them out a little at a time. Tapping them back in gets you through a season at best, because the hole is now oversized.
How far apart are the hangers?
Measure between them. Anything over 24 inches is too wide, and gaps of 30 or 36 inches will sag on their own eventually with no other fault present. See gutter hanger spacing for the full picture.
Step 2 — Check the pitch while you are up there
A gutter should fall roughly 1/4 inch for every 10 feet toward the downspout. Run a level along it. If a section is dead flat or falling the wrong way, it holds standing water, and standing water is heavy enough to pull the run down further. Sometimes what looks like a sag is really a pitch problem, and correcting the pitch as you re-hang solves both at once.
Step 3 — Clear it out first
Scoop the debris and flush the run with a hose before you fix anything. Two reasons: a packed gutter can weigh enough to hold the sag down while you are trying to lift it, and once it is flowing you can see exactly where the water still pools, which tells you where the low point really is.
Step 4 — Pull the run back to line
With sound fascia and a clean gutter, this is the part that actually fixes it.
- Start away from the sag. Begin at a point where the run is still straight and work toward the low spot. Starting at the bottom of the dip just locks the dip in.
- Fit the hooked end first. Seat the hooked end of the bracket — the end without the screw — into the rolled front lip of the gutter.
- Clip the screw end to the back wall and press until it seats. The bracket is self-bracing, so it holds its own position from here and you have both hands for the driver.
- Lift the gutter to line as you drive. Push the run up to where it should sit, then drive the screw through the back of the gutter, through the fascia, and into the rafter end behind it. The bracket pulls the gutter up tight as the screw seats.
- Do not reuse the old holes. Move a few inches into sound wood.
- Fill in the spacing. Add hangers along the whole run at 18 to 24 inches, not just at the sag. If one point dropped, the rest is carrying more than it should.
Keep the driver square and stop when the head seats. Overdriving pulls the bracket out of line and you will see it from the ground.
The part people get wrong
The screw has to reach the rafter end, not just the fascia. Fascia is trim. It is a board nailed to the ends of the rafters and it is not structural. A hanger screwed into fascia alone will hold for a while and then pull through, usually taking a chunk of the board with it. The rafter ends are behind the fascia at regular spacing, and that is what carries the gutter.
Why hidden hangers rather than more spikes
A screw thread bites into the wood and stays engaged through the wet, dry, freeze and thaw cycles that push a smooth spike back out. That is the whole difference, and it is why re-spiking is an annual job and re-hanging with hidden hangers generally is not. We went through the comparison properly in hidden gutter hangers vs gutter spikes.
Hidden hangers also sit behind the gutter lip, so the repair does not leave a row of nail heads across the front of the house.
What to order
Match the hanger to your gutter size — 5 inch or 6 inch. If you are not sure which you have, measure across the open top rather than the outside face.
For a repair, buy enough to re-hang the whole affected run rather than just the dip. Our packs run from 10 up to 500 and are listed on shop by pack size. Every hanger ships with the screw already fitted, and one 1/4-inch nut driver does the job — the full sequence is on the installation guide.
If you want to talk through a specific run before you go up, call (732) 730-7334.
Common questions
Can I fix a sagging gutter without replacing it?
Usually. If the trough is straight and not split, re-hanging it costs a fraction of replacement. Most sagging gutters are a fastener problem, not a gutter problem.
Will new hangers pull the sag out on their own?
Largely, yes. The bracket lifts the run as you drive it. Work along the run from one end rather than starting at the low point, so you are not fighting the sag from both sides.
How long does re-hanging one elevation take?
An afternoon for most single runs, once the gutter is cleared. The screw is already fitted in the bracket, so there is no hardware to sort at the top of a ladder.
What if the fascia behind it is soft?
Replace the board before you hang anything on it. No hanger of any kind holds in rotted wood, and the screw needs to reach the rafter end behind the fascia to carry the load properly.