Dense pack exterior walls with cellulose insulation

[goingreen]

This was a difficult retrofit because it already had fiberglass batt insulation. The owner wanted the 50 year old owens corning fiberglass out, which was a wise decision because it was installed poorly and had many smaller stud cavities and framing corners where it was missing altogether. Most importantly, this house had a lot of air infiltration into the exterior wall cavities from the outside because it lacked a continuous barrier. The bottom half was brick, but the top half was fiberboard with 2 horizontal 1x4 for nailing the vertical redwood siding onto. That meant there were four 1/8' linear gaps in the exterior shell surrounding the entire house! See this video for more on that viewtopic.php?f=12&t=125

First we removed the redwood siding and the middle section of the brown fiber board. Then we pulled out the old fiberglass insulation batts. Fortunately they were stapled on the inside of the stud instead of the face of the stud - so they pulled out without too much trouble.

After putting the fiber board back we drilled our 2 inch hole and dense packed with cellulose insulation. There were several small cavities such as where an interior wall meets the exterior wall as well as the corner framing that had no fiberglass insulation at all. By adding cellulose we increase our r-value to near 4.0, we greatly reduce air flow in the stud cavity and we do not have to air seal the exterior wall top plates (the cellulose seals the stud cavity from the inside). This is a low pitch roof ranch and there is just no way to air seal the exterior wall top plates from the inside. Its difficult to even reach the top plate from the attic much less get a foam gun pointed in the correct spot.

[adam12]

Thanks for that video! I never thought anyone would remove old insulation and replace with new, but in this case you had the perfect opportunity to do it. How much did you charge for a job like that?

[Smazz]

I will prob have to do something similar.
The old insulation is barely insulation at all.

I agree, thanks for posting.

[jeff3000]

Can dense pack be achieved using a Intec Force 2 blower? From looking at their manual it says to drill two 2" holes, each 17 inches from top and bottom of the bay, which to me indicates it can't. The Force 2 seems to be the only machine I can find here locally to rent and no one has the 1 1/4 hose, just 3 inch. Perhaps filling is close enough? dense pack overkill? Would love to do this project myself, but also want it done right. Any thoughts greatly appreciated. thx.

[goingreen]

A Intec Force 2 from a rental/building center is just asking for headache. According to the Intec Force web site these machines are acceptable to blow sidewalls, but that is with the heavy duty blower option and they still say nothing about dense packing. Two hole methods are not dense packing.

Another problem with rentals is that they are frequently not maintained well, and the blowers may need to have the seals replaced. Some operate at less than 50% original power.

There's no way dense pack is overkill, but if it makes you feel better there are still thousands of homes blown every year with the old 2 hole "blow and go" style. Its kinda disappointing though, like putting a hot dog in a brat bun