1948 Southern California coastal house renovation thread

[rhizomatic]

Originally Posted by S-F

The force 1 is the predecessor of the force 2, which is a decent machine. I haven't used the force 1 so I can't say.
2.9 is all you need to get to 3.5 and up.

Thanks for confirming. I've been reading older posts of yours on this and related topics, and I already value your opinion.

Originally Posted by S-F

I really want to stress that dense packing cellulose is a bit of an art and it can't be learned from reading or watching videos. It isn't particularly difficult but it is easy to do poorly. I work with people who have done this for months and years who still do a sub par job. Your best bet would be to have or make a friend who knows how to do it and have him go through the first couple bays with you in exchange for a case of beer or something like that.

Thanks for the caution. It might turn-out moot because I might be unable to rent an adequate blower anywhere in Southern Cali. I have been to two places and called six or seven. The second to last contractor rental place said that he has equipment for extraction of dry cellulose only and does not know of anyone who rents the equipment in all of the Southland.

I'm beginning to think that my learning will be for informed contracting, not DIY.

Besides I have 1200 sq ft of crawl space to insulate, and probably a few hundred feet of tiny attic areas as well... then there are horizontal jalousie that open to the outside and do not close properly... there is a great deal to do!

[rhizomatic]

The spacing between the subfloor supports is 14" wide by 5.5" deep. In local stores I can buy R-13 faced 15" x 3.5" today in good quantity and get started. I can also probably order Owens Corning R-22, 14.5" wide by 5.5" thick and have it delivered to my local Home Depot, but I imagine there would be a little compression to secure the insulation into a space exactly as deep as the insulation is thick. I would lose one or two points in R value, no?

[S-F]

By compressing fiberglass you do loose R value. But you would probably be better off IMO. For the record I'm not a licensed engineer so this is just from experience.

[MN Renovator]

Originally Posted by rhizomatic

The spacing between the subfloor supports is 14" wide by 5.5" deep. In local stores I can buy R-13 faced 15" x 3.5" today in good quantity and get started. I can also probably order Owens Corning R-22, 14.5" wide by 5.5" thick and have it delivered to my local Home Depot, but I imagine there would be a little compression to secure the insulation into a space exactly as deep as the insulation is thick. I would lose one or two points in R value, no?

R-19 with a 10% thickness reduction would be R17.5, 20% would be R16 according to an old manual on determining heating/cooling loads that I have.

Isn't insulation normally encased between drywall and sheating with exactly the space its rated to take up? I'm not understanding the proble. If it is compressed, it would be better off to go with the 5.5" thick insulation and compressing slightly versus going with an R13. I think you'd have a moisture problem if there is any air gaps.

[S-F]

Wait, I'm confused. You floor joists are only 2x6? They aren't 16" on center? Are they not regular 1 and 3/4"" ?

[rhizomatic]

Originally Posted by S-F

You floor joists are only 2x6? They aren't 16" on center? Are they not regular 1 and 3/4"" ?

The space between joists is 14" and the on center is 15 5/8" ... the measured depth 5 1/2" ... so the joists are 2x6s. How does this affect labeling and classification of the insulation? For example, does this fit? Maybe that's too simple a question. I'll find an answer from home depot or online, but are there greener alternatives to fiberglass that will work well?

[S-F]

Originally Posted by rhizomatic

are there greener alternatives to fiberglass that will work well?

Yes. Cellulose.

[rhizomatic]

Originally Posted by S-F

Yes. Cellulose.

I'll look into it further. For the walls, I'm going with dense-pack cellulose (done by a contractor, at your recommendation and because I cannot get an adequate blower here). For the tiny attic spaces, I'll use blown cellulose too. But this part of the project is the crawl-space subfloor, and I didn't think there was cellulose that I'll be able to apply in my 2'-3' crawl space under the house. I have not found it yet, if there is. Anyway, today I am considering denim and boards.

The latest information I'm evaluating is this:
Crawl Space Insulation Myths - Crawl Spaces are cold or warm due to ventilation. Are they just trying to sell me fiberglass? I was thinking I would enclose the crawlspace during the dry months (April-Nov), and open it during the wet months (Dec-March). That would destroy denim and a paper barrier?

Moving slowly and deliberatively I have a better chance of avoiding costly mistakes... I appreciate all suggestions and corrections.

Regards,
james

[S-F]

Crawl spaces are one of those construction details that make me scratch me head daily and want to cry occasionally. Two to three feet is a HUGE crawl space! You should see some of the 10" (yes, that's ten inches) crawl spaces I've had to get into, remove all of the rotten fiber glass and dead mice and then dense pack.

The way it's usually done with cellulose is to staple up reinforced poly sheeting and dense pack behind that. Since this is your own house, what I recommend is to clean the floor and joists well (as in with a vacuum), cover everything from wall to wall with a rigid insulation of your choice and dense pack behind the boards. You eliminate the thermal bridging that way and add a casual R-14 or so. In a floor you probably have to consider somewhere north of 15% of the area to be framing lumber. That's 15% or more space which isn't insulated without breaking the framing lumber thermally. Just remember to THOROUGHLY air seal the rigid insulation. I saw a job just as I describe some other people did but didn’t air seal the boards and it was mind numbing just how cold the floor was in that area. Also if you don’t tape and foam it all the cellulose would have fuzz blowing out of every little gap, and that’s not fun for anybody.
As far as ventilation is concerned, if you can make the floor impenetrable you have nothing to worry about so just keep it ventilated all the time to deal with potential moisture problems.

[rhizomatic]

Having completed some roof work to stop some leaks, I contracted with a person for the dense-pack blown dry-cellulose insulation into my walls. Though they show up Thursday, I have concerns. The sales person seemed to understand all my concerns about equipment being adequate to the pressure needed. Angie's List reviews gave them an "A" rating on the basis of 100 entries. But the technician with questions has me a little concerned, so I hope someone here will give me feedback. He did not understand my questions about the equipment. He seemed not to know what I was talking about when I asked about the pressure needed for a genuine dense pack that will not settle over time. And he does not insert a hose into the voids. Instead he just has a fitting, a reducer, to allow his machine to pump the cellulose through the hole in the wall. And he won't go through the outside, behind the siding. All the work will be done with small hole inside, that they will patch. My gut tells me to cancel this appointment, but there are few contractors here that even claim to do dense-pack dry cellulose (Californians are just not big on insulation). Are his methods sound?