🏠 Your roof assembly – Part 2: Underlayment

This week I’m doing a series on the parts of your roof assembly.

Why it matters: Once a re-roof is completed, you can’t see if it was done correctly.

  • It’s up to you as a homeowner to hold your contractors accountable.

🔬 Zoom in: One of my mentors said it this way, “A roof is no better than its underlayment.”

  • Building code requires underlayment to protect your interior with a “belt and suspenders” approach.
  • When all the underlayment is installed, we say that roof is “dried in” — meaning it could rain and the system of underlayment would shed water from the roof.
  • When shingles are installed on top of good underlayment, you have double protection from the elements.

⚙️ How it works: It starts with a clean roof deck.

🚨 Be on the lookout during a re-roof to make sure the roofers ARE NOT installing new underlayment on top of the old.

  • Most contractors are using the superior synthetic felt these days instead of 15 pound felt paper —> the additional cost for synthetic is < $200 for an average roof.
  • Synthetic felt sheds water better and provides a safer surface for the roofers to walk on when the roof is steep.
  • Ice and water shield comes in rolls and is self-adhering (it sticks to the deck) and self-healing (it seals around the nails that go through it)
  • Ice and water shield should be installed in vulnerable places on the roof —> in valleys, around penetrations like plumbing pipes and wherever flashing is required like around skylights, chimneys and second story intersections.

✅ For your Smart Homeowner list



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