Attic air sealing and adding blown insulation

Following as I want to do the same. That you have batt insulation in the attic currently would certainly make this an easier DYI job of sealing attic air leaks prior to having added blown in insulation. I have blown in and moving that aside to seal leaks before adding additional insulation is not very appealing.

My intent is to hire someone to blower door test to determine/identify significant areas of leakage first, and go forward from there.

I did the cellulose insulation and bought everything at home depot. The blower/ hopper I rented at home depot also.It ran me about 400 for everything. Made my wife feed the hopper and did it myself. Goes really fast did the hole howse in about 2 hours. Added 6 inches of thickness over my old fiberglass insulation. The next month my electric bill was cut by 30%.

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if you do just blown cellulose, it will settle and seal very well on its own. You won't gain a whole lot by caulking the gaps with blown cellulose.

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If I already had blown up there and it was a pain to move it all to apply the sealant I may not worry about it, the batt is just too easy to move aside that I might as well do it before adding the blown.

Yes we did. This was and older house. around 2000 sf house. hip roof old style 4 on 12. My wife was not happy on feeding the hopper. She was covered from head to toe . It's a little messy. Just make sure you put the hopper outside. I think at the time a bundle was around 3 bucks and used around 90 to 100 bundles. the hopper was at the time around 150 rental with 200' hose.

Holly crap i just checked home depot on the website. And the bundles if you buy 100 are more they are $8.18 a bundle. 11 bucks for single. they were 3 buck 5 years ago. fkn inflation. So if you do it yourself looks like now it will run you about a grand.
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Hm I wonder how many bags I'd need, my house is 2 story so my attic is smaller than 2000 square feet.

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Can I assume you would recommend air sealing recessed canned light fixtures, and other potentially large, though few in number, attic infiltration areas prior to adding blown in cellulose?

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sealing the penetrations will only help things. I can't remember all the details off the top of my head but if nothing else, sealing penetrations before blowing cellulose may help reduce initial "dust" that will settle into your interior spaces from the attic cellulose until the cellulose settles fully. With blown cellulose, I think the benefits of caulking from an energy standpoint are in the 2-3% range but I will look for some documentation on that.

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I have blown in R-30 fiberglass which off course has settled to some degree over 25 years, and I would like to go to at least R-38. OK to add blown in celllulose over blown in fiberglass?

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Yes! It is called capping. Capping blown fiberglass with a good thick layer of cellulose will actually improve the R rating of the fiberglass at cold temperatures in addition to the added R value from the cellulose. Oak Ridge National Labs had some good research on this topic.

Was in my attic scoping out the scene yesterday. My home is 2 stories but some sections are 1 story so there are multiple parts to my attic, one of which ill have to climb down to through a smallish gap......should be fun.

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Side question.

I am getting quotes go have work done in my attic, Northern Indiana. I have a quote to fill it with blown fiberglass to R30 and they threw in an upgraded quote to fill it to R38 instead for an additional $190.

Is the functional difference between R30 and R38 worth that?

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There are calculators out there to help if you are trying to decide based on length of return on investment. IMO, yes, that is cheap. I would go as high as I could afford. Where I am at in KC, R50 would be a good target. We may get colder than you, though.

Looks like energy guidelines also recommend R50 for your area. IN that case, it probably has a very quick payback.

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EDIT: oops, crawdude beat me. I should have read the whole thread. Sorry.

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All it takes is one misstep in an attic. No thanks.

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Could have been worse. He could have straddled the ceiling joist and pushed his nuts up to his throat. I'd take an 8 ft. drop over feeling my nuts move every time I swallow for a few hours.