Massachusetts R-value needed for basement finish


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Old 07-13-12, 06:41 AM
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Massachusetts R-value needed for basement finish

Hello,

Anyone happen to know the building code in MA and what R value is needed when I finish my basement? Is R-13 enough?

Also, if I use unfaced insulation between the studs, how can I make sure they won't fall/slide down with time?

Thanks.
 

Last edited by SBI; 07-13-12 at 09:18 AM.
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Old 07-13-12, 04:39 PM
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Anyone happen to know what R value is needed when I finish my basement?
You can enter the first 3 digits of your ZIP Code, plus some basic information about your house - construction type, heating and cooling systems, existing insulation, stuff like that - into the ZIP-Code Insulation Program to learn that.
 
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Old 07-13-12, 06:54 PM
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You are under the 2009 IECC per your State amendments; http://www.mass.gov/eopss/docs/dps/i...iecc-final.pdf

You will find the current requirements here: 2009 IECC Climate Zone Map - Massachusetts

Fiberglass in a frame wall in the basement may not be the best way to go......http://www.buildingscience.com/docum...study-analysis

Nashkat, I was using that link on this forum in 2009, when it was a year old. Most States have updated to the 2009... you are welcome to use this, if you desire: 2009 IECC Climate Zone Map

Gary
 
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Old 07-13-12, 08:42 PM
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Fiberglass in a frame wall in the basement may not be the best way to go......http://www.buildingscience.com/docum...study-analysis
Agreed. That said, I notice that your link leads to a 71 page document, with no indication of which part might be relevant here.

I appreciate the rich resource that you're sharing, but I wish that I could quickly find my way through it to the parts that particularly apply to the OP's question.

Nashkat, I was using that link [the ZIP-Code Insulation Program] on this forum in 2009, when it was a year old. Most States have updated to the 2009... you are welcome to use this, if you desire: 2009 IECC Climate Zone Map
Gary, I enjoy and use the 2009 IECC Climate Zone Map. In fact, I may have first found it through following a link you posted. But the reason I keep using the ZIP-Code Insulation Program, and referring members to it, is that it drills down to include the specifics of construction type, energy supply and comfort systems for the structure in question. That is what makes it more valuable to me.

BTW, IIRC, I was using that program in the late 1980s. Certainly well before 2009.
 
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Old 07-14-12, 07:26 AM
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Thank you all.
I spoke with the building inspector. Minimum needed is R10 and I will be using R13 fiberglass in the walls. I would use a higher value, but in some spots the wall is right against the foundation and I really don't have enough room for thicker insulation (the unfaced R13 is 3.5" thick).
 
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Old 07-15-12, 03:57 PM
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You won't use unfaced for obvious reasons as you mentioned. If the basement is totally below grade it is geothermally correct to begin with, as the temperature will not change from season to season appreciably. R13 is sufficient as indicated by your inspector, so I would install kraft faced stapled to the studs to keep it from settling. It will provide your moisture barrier (minimal at best, however). With that said, using a product like Roxul will not result in settlement between the studs. Just add a poly vapor barrier over it before you apply your final wall covering.
 
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Old 07-15-12, 05:29 PM
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Actually, I am using unfaced. Reason is, I already have a vapor barrier on the entire basement wall. I did a drain system around the perimeter and part of it is installing clean-space which is a vapor barrier, from the top of the foundation all the way down (connected to the drain channels).
I will try (not sure how it works) to use insulation support (16").
 
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Old 07-15-12, 06:19 PM
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If the basement is totally below grade it is geothermally correct to begin with, as the temperature will not change from season to season appreciably.
You say this a lot and I was wondering what exactly you mean by this?
 
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Old 07-15-12, 06:30 PM
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Droo, it is similar to geothermal heating/cooling. You run water into the ground through pipes and it equalizes the temperature year round. Run that water back to an air handler and it will blow out the same temperature almost constantly, making it comfortable all the time. Depending on where you live and how deep things are, the ground won't change temperatures and will transfer that same temperature all year long. Generally it is around mid to low 70's. So, if the walls are below grade, the majority of the dirt surrounding the walls will be the same temperature.
Now, insulating the walls at that point would be a personal preference, and not a bad idea. I just don't like to see people poking R36 in walls that won't change temperature. It is redundant.
SBI, where is your vapor barrier? If it is against the concrete, don't put another vb up. I know you may already have your insulation bought, but if you look for Roxul, you will be happier with the install.
 
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Old 07-15-12, 07:24 PM
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Yes, I already have bought rolls of fiberglass insulation.

The VP is against the field-stone foundation, and it covers the entire basement.
 
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Old 07-15-12, 09:22 PM
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On the third page in there are Chapter headings listed. F.G. on a basement wall will have problems; pp.7 (on computer), 26, 47, 69-71.

No poly below grade in basements or faced insulation, unless SPF or enough foam board directly on concrete is present; http://www.buildingscience.com/docum...lation-systems

With your frost depth at 50-60", you need insulation below/above grade; BSI-045: Double Rubble Toil and Trouble — Building Science Information

Be sure to insulate the sill and rim joist above the rubble; BSI-041: Rubble Foundations — Building Science Information

The savings can add-up fast; http://www.quadlock.com/technical_li...Insulation.pdf

If you read those links, you'll see with a frame wall and no SPF, you will experience summertime condensation on the rocks, wetting your f.g. insulation. No interior vapor barrier/retarder to dry to the inside as the only way it can. Also expect convective loops at the f.g. warming your rim joist area from the areas below (unless SPF); There's more to insulation than R-value | New Life Journal | Find Articles

Gary
 
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Old 07-16-12, 09:16 AM
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OK chandler, you hooked me up on this Roxul thing, even though it's a bit pricier compare to fiberglass. I didn't open any of the fiberglass bags that I bought and I can still return it. Same 3.5" gives me R15 compare to R13 with fiberglass.
Quesiton - on (vertical) walls, do I not need any support? Will this insulation stay standing over time, or can it collapse? I see that these are shorter bats, so I need to stack one on top of each other. How firm are these holding up?
 
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Old 07-16-12, 02:23 PM
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They are quite stiff and fit in the bay rather snugly. I have never heard of them settling down.
 
 

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