# New Construction, insulation questions



## Kylel (Jan 5, 2016)

Hello, this is my first post so bear with me:biggrin2:
I'm building new house about 4200 sq.ft. We will have 2 story family room and foyer. First floor has 10 ft ceiling, 2nd floor 9 ft, basement 8 ft. House is located near Philadelphia, PA. Outside walls constructed using 2X6.
Outside finish is Dryvit with 1.5" foam, water barrier is some kind liquid staff they used (see pictures attached). One HVAC unit is in the basement, second one is in the attic. Two electrical vents were installed on the roof along with ridge vent. So my questions are :smile::
1. What type of insulation should I use for outside walls.
2. Ceiling in the basement?
3. Ceiling on the second floor? (might be challenging, because plywood was installed on the attic floor)
4. Walls in the basement? (we're planning to have it finished)
5. Attic insulation? 
6. And the last but not least, since we have two story family room and foyer I would like to install some kind of sound insulation for the walls that facing open space and second floor corridor.

To my understanding most people recommend to use blown insulation vs batts. Currently I live in the house with no insulation what so ever, that's why I'm very concerned to do it the best possible way. I do not think I will use spray foam, I spoke with several GCs, and they were against it (please do not ask me why:smile.

Thank you!:help:


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## Bud9051 (Nov 11, 2015)

Kyle, welcome to the forum, but, I have to ask,
How in the dickens did you get this far along in the building process without having decided how you are going to insulate this. Many of the energy efficient steps are best installed during construction, air sealing being the number one. With that is the decision on where your thermal barrier will be and how it will be maintained as continuous.

The architect who drew your plans should have specified all of the answers to your questions. What are the plans calling for?

Bud


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## Alketi (Dec 20, 2015)

They covered the attic floor with plywood but didn't put insulation down first???

Are you planning on using the *entire* attic for storage? If so, the plywood will limit your insulation to the depth of your floor joists, perhaps 7" or so for 2x8s, which is below recommendations...


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## Kylel (Jan 5, 2016)

Bud9051 said:


> Kyle, welcome to the forum, but, I have to ask,
> How in the dickens did you get this far along in the building process without having decided how you are going to insulate this. Many of the energy efficient steps are best installed during construction, air sealing being the number one. With that is the decision on where your thermal barrier will be and how it will be maintained as continuous.
> 
> The architect who drew your plans should have specified all of the answers to your questions. What are the plans calling for?
> ...



Bud, we had very bad experience with our GC, architect specified only R-Values, that's it. Can you be more specific regarding air sealing? 

Alketi, yes you're correct they installed plywood before the insulation in the attic. We have 12" joists throughout the house.

BTW, drywall is not installed yet, currently they finishing up wiring the house and still have some duct work.


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## Alketi (Dec 20, 2015)

Kylel said:


> Alketi, yes you're correct they installed plywood before the insulation in the attic. We have 12" joists throughout the house.


Wow. I'm not a home builder, but that seems somewhat clueless. How were they planning on insulating the attic? Isn't there a building code in your area?

My .02 -- you'll need to pull up ALL the plywood (which isn't that big of a deal, likely either 4 screws or nails in each 4x8') and insulate those joist bays.

Blown-in cellulose is a very good option.

You should also consider how much storage space you need in the attic. If little or none, remove the plywood permanently, other than perhaps a central catwalk. That will let you blow-in 17" of cellulose which is about R60.


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## Kylel (Jan 5, 2016)

Yes, we definitely can remove plywood from the attic, 
You're saying blow-in cellulose, what about blow-in fiberglass? Should I use it on the walls as well? What about sound insulation, can you recommend anything?


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## Bud9051 (Nov 11, 2015)

Kylel,
Even if I listed a bunch of insulation and air sealing steps that should be included, that does not give you the foundation you need to do this job right. If your first architect failed to properly design this house you need to hire another one and sue the first for the added cost. It is the architect who is responsible for your design meeting all codes and it is his insurance, along with his training and experience that should be overseeing all work. They don't just make drawings, they make sure those drawings are followed.

Becoming your own general contractor carries a lot of risk, especially when you know nothing about building. You are off to a bad start and the next most important decision you have to make is not how to insulate the house, but who is going to oversee this project to be sure all work is done correctly. And I don't see how that can be you. Your permit was pulled under your GC's name. Your insurance co is expecting a properly engineered house built by an experienced contractor. They don't like insuring a house being built by a home owner acting as his own GC.

You need a pro standing right next to you.

Bud


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## HDS (Jun 21, 2014)

Air sealing the second floor ceiling is also important. Well you have lights in the ceiling of the second floor? Those boxes will need to be air sealed.


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## HDS (Jun 21, 2014)

Also, do you have ridge vents and soffitts? How will the attic be ventilated? Calling an insulation and air sealing company now might not be a bad idea especially with no drywall up.

Air sealing and insulating the rim joists between the first and second floor now would be good also.


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## Kylel (Jan 5, 2016)

Bud, I can send you a list of what was done wrong by previous GC, many mistakes, unfortunately there are a lot of GCs out there who simply know how to pull the permit and have bunch of subs. We're in the process of hiring new GC, but from now on I want to know exactly what needs to be done and how. And I do not want to listen opinion of only one GC I want many opinions from other people, that's why I came here.

HDS, we have vented soffit, ridge vent and 2 electrical vents installed on the roof.


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## Alketi (Dec 20, 2015)

Kylel said:


> Yes, we definitely can remove plywood from the attic,
> You're saying blow-in cellulose, what about blow-in fiberglass? Should I use it on the walls as well? What about sound insulation, can you recommend anything?


Kyle, both insulation types are valid, but cellulose has some advantages over fiberglass: it has a better R-value per inch, it's more fire-retardant, and it's easier to handle (not itchy).

And, as others have already mentioned, you want to AIR SEAL all the gaps in the attic floor BEFORE adding any insulation. You should also be air sealing the rim joist and sill plate in the basement (assuming those haven't been done properly).

I would start by watching these two videos which do a pretty good job of explaining the air/insulation issues in an attic as well as the difference between cellulose and fiberglass insulation. This guy also has a number of other videos detailing basement and other construction issues. Good luck!


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## Kylel (Jan 5, 2016)

Alketi, you're the best, I appreciate your help!
Thank you.


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## Bud9051 (Nov 11, 2015)

Here's a link on air sealing:
http://www.efficiencyvermont.com/stella/filelib/TBC_Guide_062507.pdf

Bud


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## Kylel (Jan 5, 2016)

Thank you very much for all your help!! Much appreciated!


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## Windows on Wash (Aug 30, 2011)

Well, you are Zone 4 or 5. Insulation requirements will vary slight on exterior wall R-Values. 

http://energycode.pnl.gov/EnergyCodeReqs/?state=Pennsylvania

Good Read on exterior foam levels: http://www.greenbuildingadvisor.com...lating-minimum-thickness-rigid-foam-sheathing

Zone 5 = R-7.5 if you have a 2x6 wall. That means with the 1.5" of likely EPS foam in the Dryvit, you need another 1" foam to meet the R-7.5 requirement if the current foam is continuous. 

Air seal the back side of the sheathing and pull up the plywood in the attic (hopefully it isn't nailed) and air seal all the top plates and penetrations before blowing loose fill (cellulose is best) over the attic. Be sure to run borate only cellulose. 

No need for insulation between conditioned spaces if you don't care. It will help with sound, but only slightly. You need to uncouple the framing to make it really quiet when talking about floors. 

Read the insulation links below for basement wall strategies and there isn't much you can do to a wall that will slow sound reflection that is part of the drywall. There are drywalls that slow sound transmission but I don't know of one that is designed to slow sound reflection. Look at the paints and as well as wall coverings for that stuff. 

Some Links that Gary has posted over the years that are good:


http://buildingscience.com/document...ng-cold-weather-condensation-using-insulation
http://www.nrel.gov/docs/fy13osti/55802.pdf
http://buildingscience.com/document...-foundation-8-xps-2x4-framing-with-fiberglass
http://buildingscience.com/documents/information-sheets/air-barriers-airtight-drywall-approach
http://www.diychatroom.com/f98/biggest-loser-fiberglass-insulation-90438/
https://www.energycodes.gov/sites/d...uide Air Leakage Guide_Sept2011_v00_lores.pdf


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## Kylel (Jan 5, 2016)

Thank you very much!


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