# Dealing with older blown in insulation



## Radcon91 (Sep 23, 2014)

Alright, to give you some quick background, I'm 23 and just bought my first house last year. It's a story and a half built in 1930, and like almost every other house of this age, every previous owner has had their way with it... One, in particular, did some horrible things to it, mostly in the wall finishing and wiring. I bought the house knowing it would need a lot of work and am doing it a little at a time.

Anyhoo, I'm looking for some advice: one previous owner, in the 80's I think, had all windows replaced and blown-in insulation put into all the exterior walls. It looks like a loose fill white fiberglass. That being said, the entire house is lined with either wood paneling or MDF board, and when I began to remove it i found the original plaster and lath to be in horrid condition in most places. So I decided I'm going to gut the entire house and hang drywall (I'm not looking for a lecture on this decision). I'm not sure what to do about the blown-in insulation when I start on the exterior walls. Is there a possibility of reusing it? Or am I better off just scrapping it and installing batt insulation? Or someone even mentioned using rigid foam... I'm doing this project a room at a time and was told spray foam would be way too expensive doing it this way.

Any advice is appreciated. 

Josh


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## Windows on Wash (Aug 30, 2011)

Don't bother try to re-use it. You will spend more time messing with it. 

Don't both with SPF either. You can air seal all you need to via some caulking and canned foam. 

Post up some pictures of the interior walls (once demo'ed) and the exterior walls and you will get more poignant feedback.


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## joecaption (Nov 30, 2011)

Balloon framed? If it is you need to add fire blocking at the top and bottom of the walls.
Has the wiring been up graded?
Going to find some interesting things when you strip those walls and old trim.
Often times no one ever removed the trim around the windows so there's going to be a big empty hole in the wall where the old weights where that never got insulated and it's common to be able to see day light.
No air sealing where the wiring and plumbing was run through the top and bottom plates.
Big voids in the insulation where it sagged and outright got missed.
Wiring nightmares.
I've found where there was old windows or even doors covered over with no insulation.
It's going to be a lot of work but well worth it.
Rent a big dumpster, buy a cheap box fan and set it in the window to help get rid of the dust.
Consider building out the walls if there just 2X4's so R19 will fit.
Just need to make some jamb extensions around the windows and door's, simple job.


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## Radcon91 (Sep 23, 2014)

I believe the house is balloon framed. What should I use as a fire stop? 

The wiring is mostly the original knob and tube with the occasional scary looking junction box where one of the previous owners hacked a piece of 2 wire Romex onto the k&t. But lucky for me, my girlfriend's father is a certified, self employed electrician, so he's giving me a hand with doing all new wiring when he can. 

I'm not sure what I'm going to do about insulation right now. My studs are mostly dimensional 2x4s, which makes me wonder if I can still use batts meant for modern 3.5" wide 2x4s. Or if that extra half inch of air space is going to cause a problem.

Thanks for the input so far.

Josh


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## Windows on Wash (Aug 30, 2011)

Fireblock with wood and a combination of drywall if you really want to get crazy.

What does the exterior sheathing and cladding consists up?

That will dictate, in large part, what is the best way to insulate the exterior wall.

You lucked out on the father-in-law.


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## joecaption (Nov 30, 2011)

Incoming power may need to be upgraded, need to contact your local power company to find out.
If it's the original panel box it needs to go and a permit pulled to replace it.
All the old knob and tube needs to go and all new wiring and outlet used.
Should have been home inspection 101, old knob and tube, deduct at least 2 or $3000.00 from the asking price.


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## AndyGump (Sep 26, 2010)

Where are you located?

Andy.


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## Radcon91 (Sep 23, 2014)

I haven't gotten far enough to know what the exterior sheathing is yet, but I'll look into it.

Joe, I'm well aware of everything you mentioned in your last post. As I said, I knew the house needed a lot of work before I bought it, and got it at a good price.

I'm located in central Iowa.

Thanks, Josh.


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## Fix'n it (Mar 12, 2012)

my money says you have plank, or even tongue & groove sheathing.


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## Radcon91 (Sep 23, 2014)

The sheathing looks like 7/8" x 9" boards, I assume that is what you refer to as plank? 

Thanks, Josh.


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## Windows on Wash (Aug 30, 2011)

Exterior cladding (siding, stucco, etc.)?

Time for some rigid board toward the outside wall and then batts. 

Whether you want an air space depends on the cladding and how it dries.


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## Radcon91 (Sep 23, 2014)

I've got slate siding for the exterior. 

But if I understand correctly, I can put a piece of 3/4" or 1" rigid foam in the back of the stud bay, air seal around it with foam or caulk, and then lay my fiberglass batt on top of that?

Thanks, Josh.


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## 747 (Feb 11, 2005)

Make sure you inspect the plumbing. It might be galvanized. If so. All needs to be replaced. Just because it looks good on outside doesn't mean big problems on inside. Can you say 20,000. Probably new electrical new insulation new drywall new plumbing. Problem with an old house. You can open Pandora's box. Its also balloon framed. Don't mess with any structure. It is for experienced carpenters only.


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## Windows on Wash (Aug 30, 2011)

Radcon91 said:


> I've got slate siding for the exterior.
> 
> But if I understand correctly, I can put a piece of 3/4" or 1" rigid foam in the back of the stud bay, air seal around it with foam or caulk, and then lay my fiberglass batt on top of that?
> 
> Thanks, Josh.


Roger that. I would keep the foam just a tiny bit off the wall to allow for some convection and any drying to the outside. 

You can rip some 1/2" furring strips as a guide but everything else you said is perfect. 

Foil faced foam facing to the outside is a great option. 

+1 to 747 on the other stuff.


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## Fix'n it (Mar 12, 2012)

Radcon91 said:


> The sheathing looks like 7/8" x 9" boards, I assume that is what you refer to as plank?


yes .........


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## Radcon91 (Sep 23, 2014)

One good thing a previous owner did was replace all plumbing with copper and pvc, so I'm good there. 

Does it really matter what thickness foam board I use? Any reason I couldn't use 1/2"? I just know they say not to compress fiberglass batts too much, since it's the air that insulates, not the fiberglass itself.

Josh


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## Windows on Wash (Aug 30, 2011)

1/2" is fine.


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## 747 (Feb 11, 2005)

Radcon91 said:


> One good thing a previous owner did was replace all plumbing with copper and pvc, so I'm good there.
> 
> 
> Josh



:thumbsup:


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## Radcon91 (Sep 23, 2014)

Couple more questions...

What should I use for caulk to seal around my foam board? Also, what's the suggested/best way to secure the foam board in the stud bay? And finally, once I put up the new batts, do I need to put up a plastic vapor barrier before I put up my drywall?

I kind of feel like I'm asking too many questions here, but I'd like to do this right the first time...

Thanks again, Josh.


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## Windows on Wash (Aug 30, 2011)

Answers:

- Any caulking or foam that is foam compliant (i.e. no VOCs). Standard Latex or Urethanes will typically work. If you have questions, do a test spot and make sure it doesn't melt the foam.

- As far as spacing the foam, rip the 1/2" foam or whatever air gap you are going to leave into strips. Use those strips to maintain the air gap. The foam can be back caulked on the spacing strips and just tacked into place with small (shallow) staples.

- You don't want to form a vapor trap and depending on the foam used, you will have a Class I, II, or III vapor retarder level there. 

Gotta know what kind of foam you are going to use but in most cases, you will not need a vapor barrier on the insulation. 

Use roxul anyway. Better stuff.


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## Radcon91 (Sep 23, 2014)

I've done some more research and made a decision on what I'm going to do. I decided to use foil backed 1/2" rigid foam and I'm going to leave a 1/4" gap between the exterior wall and the foil face by cutting some spacers from a couple of 2x4 scraps I have around. Then, as we discussed, seal everything up with caulk and spray foam. And finally put up Roxul R-15 batts and drywall over that. 

I'll also take the opportunity to bring all my wiring up to date while I have the walls opened up as well.

Thanks for the help everyone, I'll try to post pics as I go along.

Josh


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## Fix'n it (Mar 12, 2012)

so, you are saying that you are going to put all that in a 2x4 stud bay ?


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## Radcon91 (Sep 23, 2014)

Yes, I'm only 3/16" over the 4" (actual) depth of the stud bay... My 1/4" spacer, plus my rigid foam (actual measurement of 7/16"), plus my insulation meant for 3 1/2" deep studs. Am I missing something here?

Josh


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## AndyGump (Sep 26, 2010)

Might as well not use the foil face then as 1/2" gap is really not enough.

Andy.


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## Radcon91 (Sep 23, 2014)

Okay...i hope don't come off sounding like a jerk, but I'm confused. I said 1/4" gap, and windows on wash, who's been guiding me on this whole thing, said 1/2"... If it needs to be more than that, why was it brought up to begin with? I mentioned I was trying to fit all of this into a 4" deep stud bay, so I assumed we were talking about the best way to do that.

Maybe it's best if someone can explain the point of he gap and the foil faced foam. I know the gap is for air flow, but how much is enough?

Thanks.


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## AndyGump (Sep 26, 2010)

The gap from foil faced radiant barrier is not for "air flow" it is to have a dead air gap (though flowing air is better if possible) so that the radiant energy will not radiate into the living space. 1-1/2" is considered minimum for this. 

The foil (radiant barrier) is commonly recommended for locations that have a warm climate more than locations that are not considered worm so as to reflect the radiant heat energy back outside.

I have not read all previous posts from everyone and you do not sound like a jerk.

Andy.


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## Radcon91 (Sep 23, 2014)

So am I still okay doing what I said above, only not using foil faced? 

I'm starting to feel like there's no good way for me to do what I want to do here...

Josh


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## Fix'n it (Mar 12, 2012)

Radcon91 said:


> Yes, I'm only 3/16" over the 4" (actual) depth of the stud bay... My 1/4" spacer, plus my rigid foam (actual measurement of 7/16"), plus my insulation meant for 3 1/2" deep studs. Am I missing something here?
> 
> Josh


i just want to let you know = DO NOT over stuff a bay with roxul, must be pretty much flush with the stud. otherwise you are going to have bulging drywall.


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## Radcon91 (Sep 23, 2014)

So even my 3/16" over is going to cause a problem? At this point, it's either I go back to using fiberglass batts, (which I don't really want to do as everything I've read about Roxul sounds waaay better than fiberglass) and keep my air gap. Or, I get rid of the air gap and just put my rigid foam directly onto the exterior sheathing and seal it up. It sounds like what little air gap I can get is going to be pretty much useless anyway?

I'm right at the prime point to start this project since it's not too cold, but not too hot out to not have insulation for a couple of days while I do the demo work. 

Any input is appreciated. 

Josh


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## Fix'n it (Mar 12, 2012)

Radcon91 said:


> So even my 3/16" over is going to cause a problem?
> Josh


it doesn't need to be absolutely flush. but pretty close.


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## Radcon91 (Sep 23, 2014)

So I started to demo the first exterior wall in the room that I'm currently working on. People are right in saying you never know what you're going to find. Just the first stud cavity turned up a muffin tin, a child size leather shoe, some old post cards with a 1 cent stamp spot on them and quite a bit of broken glass.

Anyway, since this is a balloon framed house, I was wondering what I need to do about the space in the stud cavity that goes past the floor level (where the sill plate meets the foundation). Do I need to insulate that the same as the rest and put fire blocking at the floor level? Or can I insulate it from sill plate all the way up to my ceiling fire block? I've attached a picture to help explain.


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## Windows on Wash (Aug 30, 2011)

Should be fire blocked for both safety and air tightness.


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## Radcon91 (Sep 23, 2014)

Bit of a problem... I realized that while my interior partition walls are dimensional 2x4s, my exterior walls are built with studs measuring 1 5/8" x 3 1/2"... 

But it also looks like there's already some kind of fire blocking at the ceiling level of each stud cavity (see attached picture).










The above picture is looking up into the stud cavity










And then just what it looks like from the outside

I'm wondering if this house is a true balloon frame... What the hell am I going to do now to insulate??? I can't fit my 4" of insulation, plus the air gap in a 3 1/2" deep cavity...

Any help is greatly appreciated, cause I'm lost now...

Josh


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## Radcon91 (Sep 23, 2014)

After some thought, I think I'm going to fur out with 1x2s... Only major problem is that I've got two different floor registers on one wall that I'm going to have to move about an inch away from the wall. I hope it won't be too much work to disassemble the ductwork and cut a little off...

Josh


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## Fix'n it (Mar 12, 2012)

i furred out all of my exterior walls.


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## Windows on Wash (Aug 30, 2011)

Fix'n it said:


> i furred out all of my exterior walls.


Show off...:laughing:

In all seriousness, you are going to see such a huge difference in the home once you are done (provided you do it correctly), you won't believe the difference in performance.


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## Radcon91 (Sep 23, 2014)

I did some more research and decided I'm going to get a spray foam gun and foam my rim/band joist area. Then I'll put my fire block on top of that, and then seal everything up from there. 

Josh


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## Windows on Wash (Aug 30, 2011)

Radcon91 said:


> I did some more research and decided I'm going to get a spray foam gun and foam my rim/band joist area. Then I'll put my fire block on top of that, and then seal everything up from there. Josh


Sounds good. Post up some before and after pics.


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## Fix'n it (Mar 12, 2012)

Windows on Wash said:


> Show off...:laughing:
> 
> In all seriousness, you are going to see such a huge difference in the home once you are done (provided you do it correctly), you won't believe the difference in performance.



:laughing:

i had not been in this house, the way it was, long enough to get a lasting feel of what it used to be. but i do know it was an energy hog. now, it is very comfortable and pretty efficient. and i am not done yet.


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## Radcon91 (Sep 23, 2014)

Just for fun, here are a couple of before pictures:



















Notice the attractive flower pattern  .
. that was soon gotten rid of, along with the plaster on one wall:










Won't get back to it until this weekend.

Josh


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## Fix'n it (Mar 12, 2012)

you are going to take the lathe off ?


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## Radcon91 (Sep 23, 2014)

Yes, the lath is coming off. I'm taking the whole room down to studs. That picture is just as far as we got that day. I'll post a picture or two after we get everything demo'd this weekend.

Josh


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## Fix'n it (Mar 12, 2012)

what i found works the best. remove all plaster first, get that all out of the room. then take the lathe down. it is FAR easier to work and clean up doing it this way.


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## Radcon91 (Sep 23, 2014)

This weekend we got the north wall of the room down to bare studs. Then I put foam into my rim/band joist, sealed it off with my fire blocking and was able to start on putting my foam up. I got all of my full length pieces cut and put up, but still need to cut all my small pieces for around the window. I also got my new wiring ran for that wall, and put up my furring strips, so we got quite a bit done. I still need to do some adjusting with the furring strips to get the wall relatively flat.

Next weekend I'll hopefully get all my batts up and then move onto the west wall.

Here's a pic:










Josh


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## Fix'n it (Mar 12, 2012)

why do the furring strips not go all the way up ?


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## Radcon91 (Sep 23, 2014)

I forgot to mention, since I haven't torn down my ceiling yet, I can't do the last 6" of my furring strips. That's also in the plans for next weekend.

I didn't get as much done on this room as I wanted to, because I also decided to take down the ceiling above my back door.

I was also wondering, since this house is a story and a half, about a third of the ceiling in this room is going to be insulated. What is the best/right way to insulate that area? Can I just use the Roxul batts for 2x6 framing? 

Thanks, Josh.


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## Fix'n it (Mar 12, 2012)

Radcon91 said:


> I
> I was also wondering, since this house is a story and a half, about a third of the ceiling in this room is going to be insulated.
> .


:huh: idk what you are saying :confused1:


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## Radcon91 (Sep 23, 2014)

Sorry, I'll try to explain better: the upstairs isn't completely finished. There are knee walls on the east and west sides of the house that run north-south. These knee walls block off a part of the second floor that I would call unfinished attic space. Reading about the most common way to insulate this type of house, I need to insulate the floor in these spaces, leaving the exterior wall and roof sections uninsulated. 

Having said that, the room I'm currently doing is in the northwest corner of the house (it's a square shaped house approximately 30'x40'), making part of the area above the room unfinished attic space. Currently it is insulated with the blown in fiberglass, but I'm getting rid of that when I demo the ceiling.

I hope this makes sense  

Josh


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## Fix'n it (Mar 12, 2012)

can't help ya there. i don't have experience with that.


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## Windows on Wash (Aug 30, 2011)

Josh...post up some pictures when you can. That will help.


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## begal (Jul 23, 2014)

23, well did you do any test for asbestos?


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## cleveman (Dec 17, 2011)

I'm trying to recall what I did with my 1 1/2 home regarding the knee wall area. I think I insulated the floor and wall of the knee wall area with batt insulation. It is either this, or insulate the underside of the roof, right?


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## Radcon91 (Sep 23, 2014)

I borrowed this image from Roxul's website because it's almost exactly how my second floor is set up. It also shows how they suggest insulating this type of space. I've got dormers on the front and back of the house (south and north sides respectively). There's one bedroom, a half bathroom and a weird little space that doesn't have much use right now. Then the unfinished attic space on the east and west sides that run the full length of the house.

From some research I've done, I've found my house is a cheaper simpler version of an American Foursquare style. I lack the usual second story and big front porch, but it seems to be the closest fit with the boxy shape and pyramidal roof. 

I'm not sure exactly what I could take pictures of that would help. But I hope this helps explain better.

Josh


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## Windows on Wash (Aug 30, 2011)

I prefer conditioned knee wall zones. Easy to do with rigid foam.


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