Which insulation is better to insulate inside of stucco walls ?

Asked by Greg
Fresh Meadows, NY

I live in a Tudor style house which was built in 1940. I'd like to insulate the walls.


Lucas Johnson

Answered by Lucas Johnson

Seattle, WA

Cascadia Consulting Group

July 9, 2012

Most importantly, you will need to find a nearby expert to help you with this project.

The good insulation options are all installed with expensive and difficult to operate truck-mounted systems. I recommend starting at or searching for an energy auditor here in GreenHomeGuide's directory.

I think dense pack cellulose (or fiberglass) can be a good option for "drill-and-fill" depending on average moisture levels and indoor air quality goals.

  • Also, there are many new expanding foam options that could work well.
  • If using expanding foam, you need to make sure the expansion pressure will not crack the Stucco.
  • Lastly, remember that you will need to budget for the patching of two holes per stud bay (so probably at least 200 holes per home) and painting wall-to-wall for a nice finish.

Ideally, you are also able to install some rigid foam board underneath the Stucco to create a "thermal break" (the wood framing has very poor insulation value and is about 20% of your wall surface in an older home).

The foam board should be paired with a weep screed and other best practice water managment systems.


For more information:

Read "I want to add wall insulation to my 1920 home. I have two locally available options -- Icynene and Tri-polymer foam. Can you advise me?" a Q&A answered by Alex Georgiou.

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