View Full Version : Insulation Questions

Johann Kaple
12-29-2006, 8:28 AM
I've been doing some research on insulation online and asking friends etc and I ended up seeing some discussions on this board about icynene, foam insulaiton, attics and whatnot.
Those threads seemed to give me more questions than answers, but the discussions seemed to be filled with knowledgable people so I thought I'd make and account and see I ya'll could help me.

Basically, I bought a house last year, that was built in the 1920's. Its an american foursquare if that helps out at all. While remodeling the kitchen I found that there was 0 insulation in the walls. While upgrading the electrical, I found that there was maybe 2" of some white/grey popcorn looking foam in the attic floor.

here come the quesitons. I was considering icenene for retro fitting the walls with insulation, but now I hear there are other types of foam to consider, closed cell and open cell etc etc. Is the icynene a good choice or are there other options I should be considering. I'm sure blown cellulose or blown fiber-glass would be ok for the walls, but this house leeks air like a seive so I thought the foam would be a good "new technology".

As to the attic, my original plan was to insulate the roof with fiberglass battons. I just had the roof replaced, all new plywood and some lowprofile vents since the original roof was shingles on ceder shake and nothing in the way of ventilation at all.

Then i thought, hey, if i'm going to do the icynene in the walls, maybe I should just do that in the attic also.

I want to insulate the roof, because eventually i'd like to finish the attic. its a great space with 2 dormirs and the best view in the whole house. would be nice as a master bed/bath, if i can shoehorn in a bath. :)

So, should I be considering something other than icynene, are the home kits like tigerfoam.com ok for doing the cieling in the attic? should I just fiberglass the ceiling in the attic?

Thanks ahead of time for the advice.

Jim O'Dell
12-29-2006, 8:57 AM
Welcome to the Creek! From my limited knowledge on insulation, you don't want to use fiberglass batts against the roof sheathing. It needs air space to vent. That said, there is a spray on expanding insulation that I understand is ok to use. No air space required. But don't take my limited knowledge for gospel, let's see what the collective says, and it would be a good idea to find a trusted person in the insulation field where you live to give the best answers for that particular area. Jim.

ken brueggestrass
12-29-2006, 11:16 AM
I too am an ameteur but I've learned a thing or two during the rehab on my 1910 foursquare, also with little/no insulation.

If the attic makes up what you might consider to be the third floor, local code here says that the first floor needs to be plastered or drywall'd with 5/8 firestop. Logic: give you more time to escape in a fire if you're on the third floor.

If you insulate the floor of your attic, you can use any material you like. Those foam air dams work well but there's a newer product made out of corregated box material that has some wings to block air from going UNDER the insulation.

In my four square, it used a type of framing not seen anymore today called balloon framing. Today, you see the decking laid and the next story of wall studs secured to the top of this. In baloon framing, there is no fire stop between stories which is good and bad. You can effectively run something from the basement all the way to the top of the walls with nothing to block you.

Here's the good stuff. In houses like your and mine, you can seal the botton of the cavity in the basement then have spray foam installed from the very top through a small hole. Check out fomo-foam on the web. They have DIY kits. From what I understand, the difference between closed cell and open cell is quite significnat but one will blow the plaster/siging off the joists and the other won't. You want the one that won't. The product is essentially the same as the pros use only in a kit form that come in propane tank-like containers.

To remove the existing insulation, let's say you want to start over, you can use a leaf blower in vacume mode. Use either that leaf bag that came with it or, get big-time red-neck on your neighbors and pipe it to the outside with some laundry vent material. Seen it, funny as can be.

PM me if you like. I'm getting very close to pulling the trigger. I've also been told that the adhesive qualities of this product effectively glue your house together.

Jim Becker
12-29-2006, 11:34 AM
Ken, there really is a big difference between closed cell and open cell foam insulation products. The latter generally has lower R-value per inch, does not provide it's own vapor barrier and doesn't add significantly to the structural stiffness like the former. That said, I really caution against DIY installation in closed walls with either material...it's so easy to have major problems...that would be major expensive to fix.

Mike Williams
12-29-2006, 12:45 PM

Welcome to the Creek. I know you will get some good advice here. There are a lot of other websites available also, but one of the best is 'Old House Journal dot com'.

You can find a lot of people there with old homes that are going through the same journey you are. We were on that path years ago - I miss the results, but not the years of effort!

Johann Kaple
12-29-2006, 1:43 PM
I'll run over to old house dot com also. But from the previous threads that google sent me to here, it sounded like there was quite a bit of good minds to pick on the subject.

I believe that I do have a balloon construction. I can run things from the basement all the way to the attic using the exterior walls. I was a little surprised when i found that during my kitchen renovation.

So it sounds like closed cell is the way to go to get a vapor barrier? From one of the other threads I believe it was mentioned that icynene was an open cell but it did have a vapor barrier, is that true?
are there other good brands to look at? the icynene dealer in my area has not returned my queries.

So insulating the attic roof with battons and baffles would be ok? or should i bite the bullet and foam that also?

Charles McKinley
12-30-2006, 12:40 AM
Welcome Johann,

If you are not set on foam blown cellulose would also work at a much lower cost. You could do it yourself or hire it out. The trade off would be stopping of the infiltration.

Have you had ALL of the wiring and plumbing that would be in the foamed walls upgraded. I don't think you want to try to replace it after it has been encased in foam.

I would try to get at least two different quotes and several references for the contractor that have done the reto fit before. Some of the problems you could run into are the plaster popping off of the wall, and doors and windows not opening or closing from the over expansion of the foam.

You migh want to search for the "Green Building Alliance" or LEED certification in your area.