French Drain Pipe Orientation
Which way the perforations face in a French drain, and why holes-down lets the pipe take water in at the trench floor instead of waiting for it to rise.
Give a Buried Downspout a Way Out at Ground Level Before the Line Freezes
Fit an upside-down Y where the downspout enters the buried drain line. If the underground run freezes, meltwater exits at grade through the open branch instead of backing up the downspout, splitting it, or reaching the roofline and starting an ice dam.
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The Problem
Burying a downspout into an underground drain line gets the water away from the foundation and gets the splash block off the lawn. In a cold climate it also creates a failure mode nobody plans for: the buried line freezes.
Once it's blocked, meltwater coming off the roof has nowhere to go but back up. First it fills the downspout. Then the downspout splits at a seam under the pressure of the ice. If it doesn't split, the water keeps rising toward the gutter and the roofline — and water sitting at the eave in freezing weather is how an ice dam starts. The repair for a split downspout is an afternoon; the repair for an ice dam can be a roof.
The Technique
Fit a Y fitting upside down at the point where the downspout drops into the buried line, with the angled branch open and facing out at grade.
In normal weather it does nothing — water runs straight down past it into the buried run, and you get a small drip out of the open branch during heavy rain when the line is running full. That drip is the whole cost.
When the underground line freezes, the open branch becomes the path of least resistance. Water backs up only as far as the Y, exits at ground level, and runs away across the surface. The downspout never pressurizes, and the water never gets near the roofline.
Pro tip: Aim the open branch so that what comes out of it runs away from the house. The point of the relief outlet is to dump water at grade, and grade next to a foundation is exactly where you don't want it pooling — put it where the ground already falls away, or give it a splash block and a couple of feet of run.
This is a cold-climate detail. Where buried drain lines freeze most winters it costs a summer drip and prevents a roof repair; where they never freeze it is a permanent small leak solving a problem you don't have.
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