OSB and R3 studies

[Rusman]

I am having trouble getting my builder to install r3 sheathing underneath the siding, despite their advertising it on their feature sheet.

To help build my case, I have found all types of documentation showing energy savings with different R3 rated procucts, but these usually compare OSB only vs OSB and the R3 product. I'm looking for something that compares no OSB to OSB and or OSB w/ R3. If you can please help me out, I would greatly appreciate it!

[Rich]

Well I think I've found the same resources as you have as far as comparisons go. I did find a couple products, I'm sure you found the same, that takes the place of OSB and also provides the insulation.
I have to ask though - what do you want to do? OSB and the R3 or just the R3? You never specifically stated exactly what you wanted is the only reason I ask.

[Rusman]

CR, thanks for looking.
My situation is this: I am currently having a home built in Houston. We were offered a credit of $2000 if we went with all siding versus brick on 3 sides. We took this offer with the understanding that there would be no difference in energy costs or anything else with the siding compared to brick.

Looking at my house the other day, I found that the builder is only installing 15# felt under the siding, which is within code, however we were expecting an R3 product to be under the siding. The R3 product is advertised on their feature sheet and is installed under all brick exteriors.

So, I'm looking for any and all documentation that can support my case against the builder to get them to install the R3. From Dow I've printed out a ton of stuff showing higher energy costs without R3, but those cases only show OSB vs OSB installed with R3. Our house has no OSB installed so it's really not accurate for my situation.

Sorry it was so long, but I am very concerned about air infiltration, potential for mold growth, and having less insulation in the walls.

[Rich]

:shock:
No OSB at all? I think that's a really bad idea I don't care what any engineer, code book, or other builder tells me. Siding doesn't give any shear value to the structure. The R3 product would give some but nothing compared to OSB. My concerns are more for structural integrity rather than energy efficiency.
But in regards to energy efficiency - without some type of sheathing between the framing and the siding you will get air infiltration. There's just not a siding product that takes care of all the factors. The OSB acts like another form of house wrap and I might add much better than 15# felt. Think about how felt is installed - it's stapled. Wherever you have a staple you have the chance of ripping the tar paper. As stated, the siding goes over that and the only thing it does is give you a gap every 6" or so inches for more air to come into the house or for conditioned air to leave - either one is bad.
I don't really have a solution or anywhere else to point you. It really turns into a legal issue :evil: between yourself and the contractor. I suppose you could call Dow and talk to one of their technicians and see if they know of further studies. Most manufacturers are more than willing to help - especially if you are wanting to buy their product.

[Rusman]

Thanks again CR. I've talked to a rep at Dow a couple of times and she sent me a ton of good literature.

I think I have two big strikes against me for getting them to install the sheathing: 1)They are not violating any codes and 2)Their feature sheet says they install Dow's 1/2" foam but it doesn't say how much or where.

So, anyway, I talked to an inspector and an independent contractor today. They both stated that there is nothing wrong with the installation, I shouldn't be concerned with mold, and my utility bills won't be that much higher. I asked them point blank if it were their home, would they be concerned and they both said no. So...not sure how to take that because all the documentation I've downloaded is contrary to that. Well, I should be talking with the builder later this week or early next and we'll see what happens. I'll keep you posted.

[Rusman]

Hey CR, got an update for you.

I got a call today from the builder and they are willing to 'upgrade' our home to R-15 in the exterior walls (standard is R-13) at no charge. They will also make sure that our house is tested by a 3rd party Energy Star testing company. So, it looks like it's win-win for us. We get slightly better insulation and the house will be tested. If it doesn't meet the requirements for the Energy Star rating, then they have to fix it and retest.

I'll try to remember to come back with the test results once it's all said and done (sometime in Feb, I hope).
Thanks for the input, and happy holly-days to you!

[Rich]

That's outstanding. Glad to hear it.
I don't know if anyone has heard of Leed's before but it's a pain to be certified. It's more for large scale commercial projects but it's for the US Green Council. We spent over 6 months straight on a project to get it certified. They came back with 19 pages of comments that were so off the wall - we thought they were looking at someone elses submission. Anyway the city ended up putting a stop to the certification because it was costing so much.
In light of that I wish you all the luck. I've never certified a residential project before - it should be interesting to hear about the results.