FALL LEAVES AND ROOF VALLEYS: A PRE-WINTER CHECK FOR TRI-CITIES HOMEOWNERS
By Redemption Roofing(opens in new tab)
By late October, most of the leaves in Northeast Tennessee are coming down, and a good share of them land on roofs. Most blow off. The ones that stay tend to collect in the same place: the valleys, where two roof slopes meet and drain into a single channel.
That is worth paying attention to, because the valley is the hardest-working part of a roof. Rain from large sections of both slopes funnels into one narrow channel, so a valley carries more water than almost any other part of the roof, in a concentrated stream. It is also one of the most common places for leaks to begin.
Why packed leaves are a problem
A valley clogged with wet leaves acts like a dam. Water that should run straight down the channel backs up and spreads sideways toward the shingle edges on either side. Damp debris also holds moisture against the roof for days after a storm, and once the weather turns cold, it gives ice a place to form. Homes under mature hardwoods deal with this every fall.
A quick check from the ground
You do not need to climb onto the roof to spot most warning signs. With a pair of binoculars, or from an upstairs window, look for:
- Leaves or pine needles still packed in a valley days after a rain
- A bare, shiny, or worn track running down the center of a shingled valley
- Rust stains or separated seams in a metal valley
- Shingle edges lifting along the valley line
- Heavy granule buildup in the gutter directly below a valley
- Inside the house, a ceiling stain beneath a spot where two roof sections meet
If you see any of these, it is worth having the roof looked at before winter.
How the valley was built matters
Valleys are not all built the same way. Some use an exposed metal channel, called an open valley. Others run the shingles through the valley, either trimmed along a line or woven together. All of them can meet code, but they behave differently once debris and ice are involved. A smooth metal channel tends to clear leaves and shed meltwater more readily, while shingled valleys give debris more edges to catch on.
For the full comparison, including what the Tennessee Residential Code requires for valley lining, see Redemption Roofing's guide to open vs. closed roof valleys:
https://www.redemptioncrs.com/
A note on safety
Clearing a valley usually means getting on the roof, and wet leaves on a sloped surface are slick. If your roof is steep, high, or simply makes you uneasy, leave it to someone with the right equipment.
