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I had to repair a small section of drywall in my house so I inspected how the walls were insulated. The walls are framed out of 2x8 lumber with the bottom plate being screwed to the concrete flooring in the house. The insulation is r19 with the vapor barrier on the inside wall. This leaves a gap of a couple inches between the insulation and the chipboard. After that is housewrap and vinyl siding. In the winter months, the house feels cold even though it may be 68 inside. I can feel air coming in around plugins as well. I have been contemplating removing my siding and chipboard so I can add maybe some r11 to the outside. Should I do this? Or is the air gap a good thing in the wall? Also should I put a vapor barrier underneath the chipboard as well? Thanks.

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Discussion Starter · #3 ·
Located in southern Kentucky. The sheathing is in good condition. I had part of the siding off before when I replaced a door. As far as the 2x8 walls, the exterior walls used to be log. The logs were not maintained well and we're replaced.

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Not sure that you need to remove the wood here then.

No vapor barrier on the exterior as the wall needs to dry in one direction or the other.

I theory, you could drill and fill from the exterior, but you will probably have to compress the existing insulation to get proper and dependable fills.

Short of that, you can definitely air seal the exterior sheathing and clad it in some rigid foam to help with the thermal part of the equation.

The thing that you will need to consider is that you will likely need 2" of rigid foam to the exterior as compared to 1" given your significant wall depth and what will likely be your outside framing edge temperatures.

https://energycode.pnl.gov/EnergyCodeReqs/?state=Kentucky

http://www.greenbuildingadvisor.com...lating-minimum-thickness-rigid-foam-sheathing
 

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Discussion Starter · #5 ·
Installing 2 inches of foam over the chipboard is more work than i can do at this point. I would have to reinstall all of my windows and also i have an upstairs deck to deal with. Maybe another time i can tackle it but right now its a no can do :/

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Welcome to the forums!

" I can feel air coming in around plugins as well. I have been contemplating removing my siding and chipboard so I can add maybe some r11 to the outside. Should I do this? Or is the air gap a good thing in the wall? Also should I put a vapor barrier underneath the chipboard as well?"------------- pull the sheathing a panel at a time, add some unfaced R-13 FG (compressed is fine)- even fire-foam in a can around the electrical boxes/wiring-plumbing holes in top/bottom plates if you want- ADA the sheathing... or add another housewrap to air seal. Imperative to stop the convective looping from that gap next to sheathing robbing you of about 60% rated R-value now- plus the house condition air feeding it.

No foamboard with your vapor barrier as is... possibly-- if only asphalt faced FG- but foamboard is not even recommended per code or BSC for climate less than Zone 5- especially 2"- imagine the cost compared to adding more FG...; http://buildingscience.com/document...ulating-sheathing-vapor-retarder-requirements.

Gary
 

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Good catch Gary. Should have specified what type of foam in this case if you go that route.

See the previous remarks about exterior vapor barrier.

Plenty of sheet EPS foams are available that will give you all the perm rating that you need to maintain the walls ability to dry out. I agree that is is probably overkill given the climate, but the fact that there will be nearly R-26 in the wall means that they outside edge of that sheathing is going to be ice cold. If there is any moisture in that wall system, it will far more likely to condense on a supremely cold framing edge.

Couple that with an airtight exterior sheathing and that moisture can't as readily move to outside.

Something to keep in mind.
 

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Discussion Starter · #8 ·
Alright so i shpuld add r13 faceless fiberglass insulation to my walls. Im a little lost after that though. What do you mean by ada the sheathing?

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"Plenty of sheet EPS foams are available that will give you all the perm rating that you need to maintain the walls ability to dry out. I agree that is is probably overkill given the climate, but the fact that there will be nearly R-26 in the wall means that they outside edge of that sheathing is going to be ice cold. If there is any moisture in that wall system, it will far more likely to condense on a supremely cold framing edge."----- -- -----not with his interior vapor barrier... 1/2" foamboard (R-2.5) for his climate to prevent condensation is not worth the work involved and still have a big gap to the sheathing inside the cavity.
"Couple that with an airtight exterior sheathing and that moisture can't as readily move to outside."--- ---- ---- VB on inside and air seal with WRB OR panels ADA, I really doubt he will worry about moisture... air seal is totally different than a vapor barrier; http://buildingscience.com/documents/reports/rr-0004-air-barriers-vs-vapor-barriers/view

ADA; caulk the wood framing to sheathing, at least at perimeter. http://www.buildingscience.com/documents/information-sheets/air-barriers-airtight-drywall-approach/

Gary
 

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That's all fine and true Gary, but in order to have ADA in this case, please explain to him that he is going to need to remove all of the sheathing as well as most of the insulation to expose the backside of the drywall so that he can air seal every penetration as well as the bottom and top plates.

How do you plan on doing that if the room side insulation is installed via stud stapled flanges?

Sounds great in practice, but it will be an undertaking to remove all of that insulation to get to ADA standards. As we both know, any small gaps and air movement in that insulation will move a bunch more moisture through it as compared to diffusion.

derekeh....keep in mine that when you remove all of that sheathing as well, you are going to be torquing on that wall a good bit. Be prepared for some drywall cracks on the interior surface to touch up.
 

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That's all fine and true Gary, but in order to have ADA in this case, please explain to him that he is going to need to remove all of the sheathing as well as most of the insulation to expose the backside of the drywall so that he can air seal every penetration as well as the bottom and top plates. -------- I stated to ADA the SHEATHING, not the drywall. I said to locate the electrical and cut through the insulation/asphalt paper to canned foam around it and the wire hole through the plate- follow the wire...

How do you plan on doing that if the room side insulation is installed via stud stapled flanges?

Sounds great in practice, but it will be an undertaking to remove all of that insulation to get to ADA standards. As we both know, any small gaps and air movement in that insulation will move a bunch more moisture through it as compared to diffusion. --------------------------- If you fill the cavity with more insulation you will limit the convective looping, especially with an 8" thick wall. You only remove the small area at the electrical box and at wire hole in plate, not all of it. It may/not be stapled on faces/sides of studs- wrong side to do it all- the ADA is for sheathing. Once you plug the holes from wire, and you have a vapor retarder/barrier inside, and you air seal the sheathing--- which stops the interior air from exfiltrating through the cavity, no water will enter without a major exterior leak in the roof/wall. By adding the compressed FG, it stops any convective loops because of the density. The temperature of the exterior wall at the sheathing (because of more insulation) is not an issue, IMHO, because his low average of 45*F is not cold enough to worry about; https://www.currentresults.com/Weather/Kentucky/average-annual-temperatures.php In fact BSC/Code doesn't require a vapor barrier in Zone 4a or 4b due to moisture in the wall is NOT a problem; http://buildingscience.com/document...sheet-310-vapor-control-layer-recommendations So where, exactly is this moisture coming from?

derekeh....keep in mine that when you remove all of that sheathing as well, you are going to be torquing on that wall a good bit. Be prepared for some drywall cracks on the interior surface to touch up.
--------- first, if you use a nail puller and remove the nails- one at a time, the sheathing will fall off. Removing one nail at a time doesn't shake the wall enough to cause a drywall crack, in fact- I have never ever seen drywall crack, except before installation to a wall/ceiling- or a tree. Plaster will crack but usually it is keyed in so well you can remove one whole side of an interior wall and not even harm the other side's plaster finish. With drywall, you may get a fastener pop but that is far different than a "crack". Actual remodeling experience (years) is very helpful in answering a lot of questions. I'm sure Erik can answer some window questions better than I could... Gary
 

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You could also add some roll insulation used under vinyl siding (closed cell, R-2, or R-3----- 4.5 perms) before the WRB to air seal rather than caulk all the sheathing perimeter... just tape the seams.

Gary
 

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Thanks for the uber secret tool tip about the nail puller. Sounds fancy.

Without knowing how and what was used to attach the framing, to claim that you may not impact the interior wall finishing is probably foolish. 2x8s will be much more deflection resistant here than standard 2x4 framing, but if they attached the framing with some long'ish framing nails, even using a magical nail puller will create some wall stresses.

We even discuss this potential with clients when we are pulling siding with 1.5" nails in it. You won't typically have any large issues in the open areas of the drywall, but you can get nail pops and areas around window trim and jamb extensions are more prevalent.

Seeing as more air leakage, on average, comes from the cumulative areas of top and bottom plate gaps and seals, I will stick to my original concerns regardless of fishing through every wire and electrical outlet box. You are going to spend a good bit of time pulling off each piece of sheathing and sorting through all the insulation for every penetration, wire, and envelope breach.

I would recommend that you get puddy pads for the back of the boxes as they are more inert than foam here and will probably be easier to put on and get tight. You can order them online from Hilti or other places. Most contractors withexperience and that do this type of work know about those things.

Good luck with it. Sounds like a pretty good project by the time you pull the stuff but hopefully you can segment it out and just work down the walls in order.
 

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Discussion Starter · #14 ·
Im not too concerned with the drywall. If it cracks then i will fix it. I have 3 walls i want to work on. The other wall has a garage on the outside of it so its not much of an issue. Im confident that i can finish a wall in a day. I would like to do the back wall of my house first as it seems the worst as far as feeling air around recepticles and such. It also happens to be the shortest wall. I dont think sealing around outlet boxes and wiring will be that bad. Im still unsure if i should add insulation or not though.

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Thanks for the uber secret tool tip about the nail puller. Sounds fancy. --------------- actually, it took me about 5 years to find the best nail puller, while I used many, many inferior ones during 27 years of framing houses and 7 years of remodeling.

Without knowing how and what was used to attach the framing, to claim that you may not impact the interior wall finishing is probably foolish. 2x8s will be much more deflection resistant here than standard 2x4 framing, but if they attached the framing with some long'ish framing nails, even using a magical nail puller will create some wall stresses.--------------- the framing should be attached with "longish" nails, it is the sheathing that would require only 2" or max. 2-1/2" nails. Surprised you don't know the terminology.
"TABLE R602.3(1)-continued FASTENER SCHEDULE FOR STRUCTURAL MEMBERS

ITEM DESCRIPTION OF BUILDING
MATERIALS
DESCRIPTION OF FASTENERb, c, e SPACING OF FASTENERS Edges
(inches)i Intermediate
supportsc, e
(inches) Wood structural panels, subfloor, roof and interior wall sheathing to framing and particleboard wall sheathing to framing 30 3/8″ -1/2 ″ 6d common (2″×0.113″) nail (subfloor wall)
8d common (21/2″×0.131″) nail (roof)f 6 12g 31 19/32″ - 1″ 8d common nail (21/2″×0.131″) 6 12g 32 11/8″ - 11/4 ″ 10d common (3″×0.148″) nail or
8d (21/2″×0.131″) deformed nail 6 12" from; http://publicecodes.cyberregs.com/icod/irc/2009/icod_irc_2009_6_par013.htm?bu2=undefined


We even discuss this potential with clients when we are pulling siding with 1.5" nails in it. You won't typically have any large issues in the open areas of the drywall, but you can get nail pops and areas around window trim and jamb extensions are more prevalent. ------ Remodel requires informing the clients... remove pictures from walls, clear area, etc... in that 7 years we had three nail pops. Even 2x4 studs are pretty resilient, try a different puller.

Seeing as more air leakage, on average, comes from the cumulative areas of top and bottom plate gaps and seals, I will stick to my original concerns regardless of fishing through every wire and electrical outlet box. You are going to spend a good bit of time pulling off each piece of sheathing and sorting through all the insulation for every penetration, wire, and envelope breach. --------- simple, really. Measure the box on the inside, locate it by measuring outside, pull that area of the insulation at that side of stud only, vapor barrier should be fastened to both sides- the other side will hold that side up. Only remove a little higher than outlet is off floor by measuring inside first. The wire hole should be easy at the plate. Don't worry about the holes through sides of studs where wire was daisy-chained to the next box. There shouldn't be much air difference to force infiltration/exfiltration of the house air with an air barrier on both sides, when it has no where to go. Super job, air seal the drywall/ceiling joints in the attic/crawlspace.

I would recommend that you get puddy pads for the back of the boxes as they are more inert than foam here and will probably be easier to put on and get tight. You can order them online from Hilti or other places. Most contractors withexperience and that do this type of work know about those things.
Good luck with it. Sounds like a pretty good project by the time you pull the stuff but hopefully you can segment it out and just work down the walls in order.
--------------- I think they are called "putty pads", since it is putty on a sheet...; https://www.us.hilti.com/firestop-%26-fire-protection-systems/firestop-putties/r4559---------- for $143 plus shipping compared to $8 for a can of great stuff to do the same 20 outlets..... a no brainer- at least for me :). And you need the foam anyway to fill the wire/plumbing holes or by more putty- minimum order is.... lol. Or a small house.

Gary
PS. Yes add the extra insulation to stop convective looping. Number/letter for rows each piece of siding on the backside as you remove it.
 

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