Vapor Barrier

Desired Outcome:

Durable, effective vapor barrier minimizing moisture migration into living space.

Vapor barrier completely covers dirt floor with sealed seams and is secured to the foundation.

Before


After


Steps

  1. Remove debris

  • This includes biodegradable matter and sharp objects.

2. Layout vapor barrier

  • Leave enough material to run up the foundation walls and overlap the seams.

3. Use reinforced barrier in traffic areas

  • In traffic areas it is required to use a crossed-linked or reinforced barrier.

  • If foundation shows signs of moisture wicking, consider installing the vapor barrier 6 inches above adjacent ground level

4. Attach the vapor barrier

  • Use one of the following options 4a or 4b to attach the barrier to the foundation

4a. Option 1: attach & seal w/ furring strips & caulk

  • Secure perimeter of the vapor barrier to the foundation at least 6" above interior grade.

  • Wrap the barrier around the furring strip two times

  • Secure to foundation with masonry fasteners. Caulk along the top of the barrier to seal it to the foundation.

4b. Option 2: attach & seal w/ butyl tape

  • Secure perimeter of the vapor barrier to the foundation at least 6" above interior grade.

  • Clean off the foundation and apply the tape to the walls.

  • Use weighted roller or other tool to attach the barrier to the tape.

5. Seal seams

  • Vapor barrier seams will overlap at least 12 inches and be sealed with Butyl tape, or other adhesive that will cure when applied.

  • Caulk won't cure and cannot be used to seal seams.

6. Attach & seal to masonry piers

  • Fasten and seal the barrier to all masonry piers.

7. Leave gap between wood and barrier

  • Cut barrier 1" to 2" short of any wood post or framing member that extends to the ground.

8. Stake down barrier

  • Stake the barrier to the ground in traffic areas and around edges of wood penetrations.

  • Install tape over the top of each stake.

9. Client Ed

  • Educate the client on things they can do to extend the life of the vapor barrier.