I'm doing a remodel of my house in Iowa, zone 5. I currently have fiberglass batts in the walls, but I'm going to open them up and re-drywall for big remodel project. Is it best to use dense packed cellulose? Would I be able to dense pack the cellulose from the inside only? Or should I just do some open cell spray foam?

It's possible to dense pack from the interior, either in mesh (preferred, since it's inspectable) or with holes drilled in the gypsum (patched after the fact- use a hole-saw and save the plugs.) If blown in mesh, specify that it be rolled flat to stud-depth after blowing to ensure flat, unbowed gypsum.

What type of sheathing & siding?

If you are taking the drywall off anyway, adding rigid foam underneath the new drywall will outperform refilling the stud bays. And add a well sealed air barrier.

Posted By jonr on 03 Jun 2013 11:51 AM
If you are taking the drywall off anyway, adding rigid foam underneath the new drywall will outperform refilling the stud bays. And add a well sealed air barrier.

You'd need at least 1.5" of polyiso or 2.5" of EPS for that statement to be true. 

Adding that much foam AND refilling the stud bays would roughly double the whole-wall R.

I wanted the benefits of cellulose (moisture buffering) for inside the wall cavity. When I reside the house (within the next 2-3 years) I'm going to add 2" of foam board insulation before new Hardie siding.

You'd need at least 1.5" of polyiso or 2.5" of EPS for that statement to be true. 

Not if you don't empty them (which was the intended meaning).

Hi, Strategery. I’m Dave Wolf –I’m the senior research and development program leader at Owens Corning. I’ve worked on comprehensive air sealing research and building science throughout my career, so I wanted to see if I could help.

With the wall cavities exposed, before reinsulating, I recommend first air sealing. Essentially, you could apply sealant to all the joints and openings in the wall cavity. For example, you would air seal where the sheathing meets the framing.

After air sealing, there are a number of options to insulate the wall cavity, including fiberglass batts and blown-in fiberglass loosefill, which involves netting the interior face of the cavity and blowing the insulation in place. If you do this yourself, many home centers offer equipment for DIY blown-in insulation options.

Not sure if it’s a small or big project, but if you need help, we offer various types of fiberglass insulation and a flexible air sealant (called EnergyComplete) – all of which can be installed by a professional contractor.

Hopefully this information is helpful.