Exterior wall blown - best practices

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Exterior wall blown - best practices

Postby homerowner » Thu May 05, 2011 10:39 pm


Just had exterior walls done with blown cell and some with fiber. House is vinyl.

They used wood and styrofoam plugs. Should they have used all wood? Should they be glued or just pounded in?
The siding was replaced without nails.
In regards to the foil paper that is under the vinyl...it was cut and when the vinyl was put on there was not attempt to put the foil back in place. What should have been done?

Thanks in advance for any help.
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Re: Exterior wall blown - best practices

Postby Twin City Insulator » Sun May 08, 2011 9:54 pm

Best practice would be to use all wood plugs and seal seam with caulk. Siding should be returned to same or better anchoring using nails or screws. Foil paper is of little or no benefit so the extra cost to have them to replace and properly tape all seams would not be cost effective.

More important than the finishing with plugs is the method used to put the cellulose in the wall. If a tube was inserted all the way up the wall and all the way down the wall you are in good shape. Hopefully the density was between 3.5 and 4.5 lbs/cu-ft and can only be determined by knowing the number of bags used.

If they drilled multiple holes (2, 3 or 4) in the each wall cavity, and ONLY used a directional nozzle inserted in the wall hole, you will likely have settling near the top and unacceptable air flow throughout the wall. We are often hired to "re-blow" such loose filled walls done by "blow and go" companies. Unfortunately, some of these companies still exist!

Also, blowing fiberglass is not a best practice. There are some expensive fiberglass products such as Spider that are supposed to compete with cellulose, but most in the field think the test results are highly questionable. Common sense says you can't pack glass and get good R value and greatly reduced air flow reduction such as found with paper.
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