Reliable Roofing Tips

One roofing detail a week · reviewed by Rob, roofer, 29 years

One roofing detail a week, the right way beside the half-way way.

Written by a working roofer. Read it as craft or as leverage — same facts, four minutes, and nothing here is selling you a quote.

You get the sequence, the spec, and the year it starts to leak.

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The detail

Valley flashing

Sample issue
Cross-section of a roof valley: two sloped planes meet over underlayment with a metal flashing channel running down the center and shingles trimmed back on both sides. An arrow marks water flowing down the metal channel.
Where two roof planes meet — the metal carries the water

Done right

  • Metal valley flashing runs the full length, laid over the underlayment.
  • Shingles trimmed back 2 inches from the center in a clean, straight line.
  • No nails in the valley center, so nothing punctures where the water runs.

Done half-way

  • Shingles woven across the valley with no metal underneath.
  • Nails driven straight through the channel the water uses.
  • Looks perfect at handover. Starts leaking around year 4.

Rob's call

If there's no metal in the valley, it's not done. Ask for a photo before they cover it.

Reviewed by Rob, roofer, 29 years.

The checklist

Valley flashing checklist

6 things to ask for a photo of, before the shingles go on and hide the work.

Sent with every issue

Time to read

4min

On a phone, Thursday mornings. Not 40 minutes of video.

A single asphalt shingle seen straight on, with the nailing zone marked as a horizontal band and four evenly spaced nail heads placed along it.

Next Thursday

Shingle nailing

4 nails, in the zone, not overdriven, not high. Sample detail.

The archive

Every issue stays a page that answers one question, forever.

The detail list is effectively infinite — flashing, fasteners, ventilation, tear-off, insurance scopes. Each detail earns its own issue and its own permanent page.

  • Valley flashingNo metal in the valley, it is not done.
  • Drip edgeUnder at the eave, over at the rake. Easy to get backwards.
  • Shingle nailing4 nails in the zone, not overdriven, not high.
  • Roof overlayA second layer hides the deck. Sometimes fine, usually not.
  • Ridge ventilationA ridge vent with no cut slot underneath vents nothing.

Sample details — shown to illustrate the format