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Bushka

Q&A Forums Registered User
Posted: 1/03/2010 7:58 PM EST

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DIY Job - Pointers Needed!
[Update: I didn't know photos couldn't be posted, sorry. I did post pic Den 1 in the photo forum but it is under moderation.]

Hi. I just completed a home rebuild. Everything above grade is new, while the den and basement are existing. The rest of the house was spray foamed (I have another thread open on spray foam gap problems). Anyway, I thought I'd try to save a few $ by tackling the den myself. If I find having a pro do it isn't much more, then maybe I'll have them do the job.

So the room is a little unorthodox. See pictures below. There are two walls partially below grade with cinder blocks halfway up the wall. The rest of the wall to the ceiling is insulated and sheetrocked (original from the 1960's). On top of the insulation is another set of studs to build the wall out flush with the cinder blocks. There was wood paneling originally nailed to this. My thought was to add spray foam directly on top of the existing sheetrock to get a double layer of insulation - leave the original alone, and add foam inside. I would add 5 R value styrofoam to the cinderblocks, and then sheetrock over the whole thing. Is there any reason not to add spray foam "on top of" the exterior layer of original, old insulation? Also, pic Den 2 shows a header above the plate on this wall. I would be spraying this as well I assume.

On a third wall (to the right in pic Den 1, and also pic Den 3) is old insulation floor to ceiling. I would replace this with spray foam as there is a garage on the other side of the wall. Above this wall is an area about 12 inches deep and ends at a 12" header. It is currently stuffed with old fiberglas. If I remove that you can see the cavity in pic Den 4. Do I just spray in this cavity and give it a good 3" coating, or should I stuff cardboard or something in there to wall off that space, and then spray the cardboard?

So if you are still reading this, I hope it makes sense. My quesions, summarized are:

1. Is it OK to spray over an existing exterior wall insulated with old fiberglas?
2. Do I spray the header above this wall?
3. Is the R5 styrofoam adequate for the cinderblock area?
4. How best to spray the 12" cavity above the third wall?
Other:
5. Can I spray the metal HVAC ducts in the ceiling that lead to upstairs rooms?
6. If I try to save money by spraying a 1" skim coat, do they make a 2 or 3 inch fiberglas to put on top of that?
7. Is this too ambitious for a DIY spray foam system? I think I can do the work, but I don't know if the DIY systems are any good.

Thanks hugely to anybody making their way through this long post!

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Mason  

Moderator
Posted: 1/03/2010 8:57 PM EST

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RE: DIY Job - Pointers Needed!
As many of you know from my forum, I am not a proponent of do it your self sprayfoam jobs. Sprayfoam applications require extensive technical training in the art of spraying foam, equipment troubleshooting, substrate preparation, masking and trimming, foam chemical handling, safety and health precautions, overspray protection in addition to a knowledge of where to spray the foam to achieve the best results.

My recommendation is to hire a professional that can show you good references on projects similar to the work you need done. DIY projects should be only for very small applications, such as crack sealing around doors and windows or non critical small areas that can be sprayed with the small 2 component bottle units. (even those take some practice to use correctly and remember to wear the proper personal protective equipment, including, respirators, nitrile gloves and chemical resistance suits. )

foamdude

Q&A Forums Registered User
Posted: 1/04/2010 4:03 AM EST

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RE: DIY Job - Pointers Needed!
without a real grip on your wall system...
a few broad generalizations,,
but appropriate for your questions none the less

1. Is it OK to spray over an existing exterior wall insulated with old fiberglas?

no,,do not spray over filterglass,,,ever.

2. Do I spray the header above this wall?

yes,,spray everything you can splatter the stuff on,,and im serious...dont forget the thermal or ignition barrier,,and dont tell me you dont have code in your area...lol...(liability to manufacturer???ooh and it makes me wonder)
3. Is the R5 styrofoam adequate for the cinderblock area?

adequate???compared to what???why not foam it too??
4. How best to spray the 12" cavity above the third wall?

with the pre-expanded froth pak systems,,good luck,,,
Other:
5. Can I spray the metal HVAC ducts in the ceiling that lead to upstairs rooms?

you could,,,but this is not code compliant,,somethin about bendin over and kissin booty with the fire folks,,,

6. If I try to save money by spraying a 1" skim coat, do they make a 2 or 3 inch fiberglas to put on top of that?

just press in a batt...your splatter foam will be of irregular enough configuration that it wont matter in the big scheme of things...

7. Is this too ambitious for a DIY spray foam system? I think I can do the work, but I don't know if the DIY systems are any good.

what mason said,,,
what i say,,your time has to be considered into the equation to make a truely informed decision..
you have to be realistic and admit that even under optimum install conditions your application will be compromised when compared to a professional installation,,duh,,go figure...
you need to remember what started your quest into researching this insulation product that actually works,,,you want performance,,,pay to have it done right...the first time,,,(dont take the cheapest bid maybe if you hire a supossed pro next time,,,lots of posers out there)
the insulation system in buildings can no longer be the cheapest system in the structure...
remodles are frequently the most complicated when trying to create the builiding envelope due to the inherent cobbled together crap you see behind the walls...spray foam excels here,,
get the most for your money,,
i provide the frothpak systems to homeys that call about rim joists and box sills,,particularly in their crawlspacefromhells...

so to paraphrase,,,
hire a pro...is my opinion..go figure...

sorry about the rant,,,
medys havnt kicked in yet...
but serious,,,i hope this helps,,

Bushka

Q&A Forums Registered User
Posted: 1/04/2010 11:57 AM EST

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RE: DIY Job - Pointers Needed!
Thanks for the replies. A photo can be found in this forum: http://www.johnbridge.com/vbulletin/showthread.php?t=80410

Regarding item 1: I wouldn't be spraying directly on top of fiberglas. If you see the sheetrocked wall behind the studs - that's what I'm talking about foaming. There is an existing layer of original fiberglas behind that drywall. Basically I don't have to do any insulation - I could just put up sheetrock, but I want to take advantage of foam's performance and block out that old insulation, rather than rip down all the studs, remove the sheetrock and then reinsulate. I could make some mistakes along this wall and it wouldn't be fatal, so to speak.

Regarding item 3: the space on the cinderblock is only 3/4" due to the lath width, so I'd only be getting 4 or 5 R value from spray, and it will be difficult for me to control the thickness that precisely. I thought I could spray foam any gaps or holes in the cinderblock, then styrofoam the rest.

Regarding item 5: OK, then just to be sure I cannot spray the HVAC ducting? Seems odd since it can't get that hot.

Any more info/pics of the frothpak system?

Thx!

caddis

Q&A Forums Registered User
Posted: 1/05/2010 9:39 AM EST

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RE: DIY Job - Pointers Needed!
You want a pointer? Here you go. Don't try to do this yourself. Hire a professional.

I'm not saying that because I am a foam installer and trying to dig up work for a colleague.

I am saying this because I have been doing this for several years and know that you cannot properly do that project with a frothpak and little experience.

Olger  

Q&A Forums Registered User
Posted: 1/05/2010 9:12 PM EST

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RE: DIY Job - Pointers Needed!
I agree.



`oG

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Bushka

Q&A Forums Registered User
Posted: 1/05/2010 11:55 PM EST

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RE: DIY Job - Pointers Needed!
I don't know if it is possible to answer a pricing question, but roughly what should I expect to pay in NJ if I have the three walls sprayed? Two of the walls are just half walls (about 15 x 5 and about 20 x 5 ft). The third wall is floor to ceiling, about 20 x 8 ft). I could apply the stryofoam to the cinderblock myself.

Aside from who does the work, is there in principle anything wrong with putting foam on top of the sheetrocked outer layer of fiberglas as I mentioned above?

Bushka

Q&A Forums Registered User
Posted: 1/08/2010 8:09 PM EST

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RE: DIY Job - Pointers Needed!
bump.

Mason  

Moderator
Posted: 1/09/2010 11:17 AM EST

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RE: DIY Job - Pointers Needed!
I don't see the photos, but let me see if I have this straight. You have an existing wall insulated with fiberglass with a drywall interior finish. You want to stud out the drywall interior and spray that with foam. ( I presume you would cover the foam with more drywall?) Is there a potential problem with that type of configuration?

There is something about that design that I am uncomfortable with.

The sprayfoam will insulate the interior wall and to some extent work against effectiveness of the fiberglass. This will make the fiberglass insulated cavity closer in temperature to the outside temperature. It will make the original interior drywall surface part of the an exterior wall assembly rather than an interior wall assembly surface. How will this affect the overall moisture resistance and energy performance of the assembly?

1. I think a WUFI simulation or other hygrothermal modeling of the proposed design will tell us what effect it would have on the condensation potential.

2. From an energy performance perspective, the sprayfoam will make the fiberglass perform less effectively than if the foam was the outside insulation element and the fiberglass the inside element. But overall will this specific design save energy? Not sure, I have not seen this specific design to be able to get some field performance history on it and have not seen any lab research on the design either.

My recommendation is to remove the existing drywall and the fiberglass, spray the cavity with foam. Then if you want to reuse the fiberglass install it over the sprayed foam. This is an acceptable practice and will provide the best moisture and energy performance for that type of hybrid insulated assembly.

Bushka

Q&A Forums Registered User
Posted: 1/09/2010 5:38 PM EST

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RE: DIY Job - Pointers Needed!
The photo of the room is the newest one in the Photo Gallery. The interior studs are already in place and are original construction. Until now, those interior studs were covered with wood paneling, and there was no insulation in the cavity between the paneling and the drywall in the photo. Since the whole rest of the house is sprayed, I wanted to complete the job. The most straightforward (ie, easiest) thing is to just spray the existing sheetrock, but like you say, I didn't want to create unintended consequences.

You make an interesting point about the foam reducing the effectiveness of the fiberglass. Now, if I were to fill the interior cavity with fiberglass instead of foam, then I'd have two layers of fiber divided by sheetrock. Would this differ from having foam on one side and fiber on the outside? I know foam won't allow "breathing" or leakage, but is it much different than having the two layers of fiber?

timw  

Q&A Forums Registered User
Posted: 1/11/2010 9:06 AM EST

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RE: DIY Job - Pointers Needed!
Let me start off by saying, I'm a big fan of forums. The willingness for people to help is evident, with this forum being no exception. However, I believe this thread crosses the line. I've visited other professional trade forums that simply have not allowed DIY questions to be posted. While that isn't (to my knowledge) a current policy on this forum, I believe it should be. Every regular poster on this forum makes their living off of the sales, service or installation of spray foam. To be offering advice on DIY foam is basically asking someone to be an unpaid consultant and that isn't fair. Educating potential customers is one thing, but the OP has yet to indicate that he is seeking the services of a professional installer. The help, in this case, should be coming from the manufacturers of the DIY foam. My $.02, take it for what it's worth.

Bushka

Q&A Forums Registered User
Posted: 1/11/2010 4:15 PM EST

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RE: DIY Job - Pointers Needed!
Tim - I only have time at the moment for a quick reply. Check my other threads. How's paying 5 figures to a member of this forum, and still getting a defective spray job affect your opinion of my "right" to ask some questions on another job? Go look at JohnBridge.com for an example of a very successful tile site where professionals and DIYers cohabitate quite well.

If you're a moderator, take my comments constructively, otherwise, keep your $.02, with all due respect. The only opinion that counts to me is the owner of this website and those who are willing to take part in forum discussion. If he doesn't want to help me out, then he has every right. To date, he's been quite helpful with anything I've posted here.

Bushka

Q&A Forums Registered User
Posted: 1/12/2010 6:44 PM EST

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RE: DIY Job - Pointers Needed!
Also, Tim, please reread the thread. I've mentioned more than once that this might be a job I need to hire someone for.

Bushka

Q&A Forums Registered User
Posted: 1/12/2010 6:45 PM EST

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RE: DIY Job - Pointers Needed!
Mason - last question and then I'll let this thread go. If I take down the existing sheetrock and have the exterior wall foamed, and then put fiberglas on top of the foam (and then sheetrock over of course), would I be best to use a fiber with no facing, or does it not matter? I'm wondering if the facing will help trap moisture between the fiberglas and the foam.

Thanks again for your help!

Mason  

Moderator
Posted: 1/15/2010 8:03 AM EST

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RE: DIY Job - Pointers Needed!
If you are using closed cell foam in sufficient thickness for your area, you do not require an additional vapor retarder. So, in that case I would not use a vapor retarder faced fiberglass batt. Check the charts in the 2009 IBC codes for the amount of SPF insulation required in your area to prevent condensation. It can be as little as 1 inch in warm to mixed climates to over 2 inches in the colder areas.

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