Winterizing Gutters in St. Louis: The Before-the-Freeze List
The first hard freeze in St. Louis usually lands in the last week of November, give or take a week, and whatever state the gutters are in that morning is the state they'll stay in until March. Water that's sitting becomes ice; leaves that are wet become a frozen plug; a corner that was weeping becomes a corner that's open. Early October is the time to winterize gutters and work through the list below, because everything on it is easier at 60 degrees than at 25.
The list
1. Clean out, but at the right time
Not yet, if you're under oaks. The pin oaks in Kirkwood, Webster and U City don't drop until late November, so a cleaning now just means a second one in December. If you're under sycamores or maples, most of the load is down by the end of October and one thorough clean-out in early November does it. If you have both, the fall leaf calendar has the timing. Whatever the tree, the gutters need to be empty the week before the freeze, and every downspout flushed and flowing from the top. A downspout with a half-plug of helicopters freezes solid in one cold night.
2. Fix the pitch
Stand at one end of each run after a rain and look for standing water. A gutter that holds an inch of water in November holds an inch of ice in December, and an inch of ice in a 5-inch gutter weighs about five pounds per foot. Over a 40-foot run that's 200 pounds hanging on spikes that were already loose. Re-hanging on hidden hangers and resetting a quarter-inch fall per ten feet is a $150–$300 repair per run, and it's the single most useful thing on this list. Gutter repair covers it.
3. Reseal corners while sealant still cures
Polyurethane and tripolymer gutter sealants need a dry surface and temperatures above about 40 degrees for a day to cure properly. October has plenty of those days. January has none. A corner that's dripping now should be scraped to bare metal and resealed this month, because ice forming in a cracked seam opens it further and you'll be looking at a bigger repair in spring.
4. Extensions on, and where the water goes when it's frozen
Every downspout should end six feet from the foundation. Then think about January: water that comes out of a downspout during a midday thaw and lands on the driveway or walk becomes a sheet of ice by evening. Route downspouts off paved surfaces and onto grass or a buried line before winter, and check that the bottom elbow isn't aimed at the front steps. If you've had a buried drain line installed, make sure the pop-up emitter at the end is clear of mulch, because a frozen, blocked emitter backs water up into the downspout.
5. Disconnect the rain barrel
A rain barrel left connected and full will freeze, split, and dump ice against the foundation. Drain it, disconnect the diverter, put the downspout back on a normal extension, and store the barrel upside down or leave the spigot open. The diverter kits sold at the hardware store include a winter bypass; use it.
6. Look at the roof edge
From the ground: the shingles should overhang the gutter by half an inch to an inch, and there should be a strip of metal drip edge visible under them at the eave. Without it, meltwater runs behind the gutter and down the fascia, then freezes there. This is a roofing detail, but it's worth knowing before winter, because an ice-soaked fascia is what fails when the gutter is heavy. Gutter problems that start at the roof explains it.
7. Check the straps and hangers
Push each downspout gently at chest height. It shouldn't move. Look along each run for a gap at the back between gutter and fascia. A loose downspout or a gutter with a gap goes into winter weak and comes out in March on the ground, because ice weight and wind find the loose one every time.
8. Trim branches over the roof
Branches that hang over the gutters drop debris all winter, scrape the roof in wind, and can snap under ice and land on the gutter. Have limbs trimmed back several feet from the roof edge before the leaves are gone and the wood is brittle. Work near power lines is a job for a tree company or the utility, never a homeowner with a pole saw.
9. Note the outdoor faucet and the hose
It isn't a gutter item, but it's on the same walk. A hose left attached to an outdoor faucet can freeze and split the pipe inside the wall, and a hose left lying under a downspout becomes a dam of ice. Disconnect and drain hoses after your last flush of the downspouts.
Mistakes when winterizing
- Cleaning too early under oaks. A gutter cleaned before the last leaves fall goes into the freeze half full.
- Plugging downspouts to keep critters out. Any cap or screen at the bottom of a downspout traps ice. Use a screen at the top of the outlet instead, in the gutter.
- Sealing in the cold. Caulk applied on a 30-degree morning won't cure and peels by spring.
- Leaving the rain barrel connected. It freezes, splits and sends water back up the downspout.
- Forgetting the small roofs. Porch, garage and shed gutters freeze too.
What to watch during the winter
Once the cold arrives, a quick look after each big snow or ice storm goes a long way. From the ground, look for a gutter tipping forward, a downspout pulled away from the wall, or a thick ridge of ice along the eave. Don't climb a ladder onto ice, and don't chip ice out of a gutter with a hammer or a shovel; that's how aluminum gets punctured. Make notes and photos of anything that looks wrong and have it checked in the first mild spell. After the thaw in March, walk the house again with the same list: hangers, corners, pitch and extensions.
The list, in the order to do it
| Week | Task |
|---|---|
| Now (early October) | Reseal corners, re-hang sagging runs, replace soft fascia, check straps |
| Late October | First clean-out under sycamores and maples; extensions checked; rain barrel disconnected |
| Late November, first dry week | Final clean-out under oaks; flush every downspout |
| Any time before Thanksgiving | Move downspout outlets off paving; clear pop-up emitters; note the roof edge |
What this list doesn't cover
Ice dams — the ridge of ice at the eave that backs water under the shingles — are an attic insulation problem with a gutter symptom. Heat cables treat the symptom on houses where the attic can't be fixed, and heat cables and de-icing in St. Louis goes through when they're worth the money. What ice does to the metal itself, and what to look for when it thaws, is in ice, snow and gutters.
If the list turns up more than two items, a gutter cleaning visit in early November with the inspection included is the efficient way to get all of it done in one morning, with the repairs priced from the ladder.
Common questions
Do I need to winterize gutters if I have guards?
Yes, though the list is shorter. Guards keep out leaves, but you still want the pitch right, the corners sealed, the downspouts flowing and the extensions in place. Brush any leaves off the top of the guards after the last drop so meltwater can get through.
Is it too late to winterize gutters in December?
Not entirely. Cleaning, flushing downspouts, moving outlets off paving and disconnecting rain barrels can all be done on a dry December day. Sealant work and re-hanging are harder once the cold settles in, so if those are needed, get them on the calendar for the first mild spell.
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