Replace exterior wall insulation from inside?


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Old 12-11-09, 12:04 PM
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Question Replace exterior wall insulation from inside?

Replaced my siding over the summer, had a contractor do it. I asked him to PLEASE check the plywood and insulation BEFORE he put on the new siding. I wasn't home, my wife said he checked it and it was all good. I had her take pictures of the house while he resided, the plywood was dark, looked to me like it was water logged and stained dark now from the water.

Granted we don't feel the drafts as much as we used to - old siding was that graphite crap. But if I put my hand on the 2nd floor north facing wall it's cold to the touch. I'm convinced the contractor didn't bother to look. I am fairly certain the old siding let water in. We had 6 windows replaced and the 4 north facing windows sills were just about rotted out from water damage. I believe my insulation (house built in 89) is most likely sitting at the bottom of each bay, water logged, compressed and doing nothing.

Today it's 25 outside and my pellet stove is cranked almost full and I'm only getting 78 degrees in the room it's installed in (south side 1st floor) 67 degrees in the north side 1st floor and 66 degrees at the top of the stairs to the 2nd floor. Already checked the attic, nothing wrong up there, all insulation is full and where it should be. If I stay up there and put the trap door back in place I feel no heat escaping into the attic.

I hate to have to do this, but think the only way to replace the wall insulation from the inside it to tear down the sheet rock? Too bad too because the 2 rooms I would need to do this in were repainted last spring.

Any other way to replace exterior wall insulation from the inside? I was really hoping to save on Oil bill this winter...
 
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Old 12-11-09, 01:25 PM
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I would try cutting a section of drywall maybe 12" wide in the middle of the wall down the entire length. That way you can pull the old insulation out of that hole, patch it up, and blow cellulose back in. Maybe you will need more than 12" or remove something like that from the lower part of the wall and from the upper part of the wall. Low rise expanding foam is another option to consider.
 

Last edited by drooplug; 12-11-09 at 01:25 PM. Reason: typo
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Old 12-11-09, 01:32 PM
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With your method - good idea by the way, I would not have a vapor barrier any longer. Or would I need it seeing how the pictures my wife took shows the contractor was at least smart enough to use vtek under the siding.
 
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Old 12-11-09, 02:21 PM
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Resercon Company - Home and Inspection Services: Insulation - Home Performance with Energy Star

The above link is an article I wrote about "Home Performance with Energy Star". This is actually a nationwide program but States have different names for it. I suggest you find out if it is offered in your State and take advantage of it.

Most people certified under this program will use a thermal imaging camera in conjunction with the "Blower Door". This will confirm your idea about the insulation or not. Besides this the program in your State will probably provide more information in reducing your energy costs than just adding more insulation.
 
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Old 12-11-09, 02:41 PM
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Good point about the VB. If you use closed cell foam, you won't need an additional VB. Using cellulose, you will. That certainly makes the project a little more tricky. Instead of doing 12 inches from the start, try doing something more narrow. When you go to widen the access hold, don't cut all the way through the drywall. Score it with a utility knife and try to break it off like that. You might be able to avoid damaging the vapor barrier. By having that margin of exposed VB, you might be be able to overlap the replacement and tape it at the seam, then cover with the drywall. Try this method on one or two bays before you go all out. If you decide you are willing to tear the whole wall down, then it certainly won't hurt to try my method.

I've read about vapor barrier paints. I know they aren't as good as having the plastic VB, but may be an option. Investigate the perm ratings of them and see how they compare to the plastic sheeting.
 
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Old 12-11-09, 02:48 PM
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Just the thought of cutting open the finished room when the contractor could have done it much less painfully from outside when the old siding was down... it kills me.

I just remembered I have a crawl space I can get into to see the west wall, we have a Gambrel, the west wall on the 2nd floor is behind the Gambrel roof so I can get in there thru the closet and look at the existing insulation. North wall, no luck there, I'll be cutting a hole. Crud.
 
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Old 12-11-09, 03:12 PM
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Try picking up one of those IR thermometers. You can shoot it at different walls to compare their temperatures. You can get one on Ebay for roughly $26. Do it at night to make sure you aren't comparing walls that have been heated by the sun to ones that havn't.
 
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Old 12-11-09, 03:53 PM
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Just a couple of comments.
1. The contractor only replaced the siding? right? If that is so, he never saw the insulation, it is behind the sheathing/plywood.
2. The new siding would have very little to do with heat loss, unless you/he added some rigid insulation under that siding.
3. How thick are the walls? If 2x4, then extra insulation (rigid) should have been added, regardless of the condition of what is there.
4. What type of siding did you put on? If vinyl, then when warm it can easily be pulled back to inspect the plywood. Just need a reasonably warm day, which we don't have right now, and the contractor can do that.
5. Take a look at the pictures again to see if the dark plywood was the plywood or tar paper, common in 89.
6. Your concern that your insulation is gone is best confirmed before you tear into those walls. As resercon suggested, an energy auditor with an IR camera or the full audit would answer that and more. IMO, your insulation is still there and functioning, just not enough. And that gets back to how thick are those walls?

Whether you do an audit or you hire an auditor, knowing where your heat is going is the first step to take before you decide to add more insulation. The sad part is you are probably correct that the siding guy should have told you some of this and sold you some extra insulation when it was easy to install. But get some numbers and then you will know what direction to head.

Have you addressed air sealing? It is number one for heat loss and number one for being an affordable easy fix.

Bud
 
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Old 12-11-09, 04:54 PM
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1. Yep, just replaced siding but I did ask him to pull a sheet back, never happened.
2. No added rigid insulation, wouldn't be thinking about replacing the old if that were done.
3. 2X6 - confirmed twice
4. Vinyl siding, hate to pull it off to do this but that might be the lesser of two evils...wait till summer and start over?
5. Plywood for certain. You can even see where the nails have streaked and stained the wood from the water damage.

(sorry can't get an image or a link to work to show you)


What's this about air sealing? Time to google...
 

Last edited by fnworks; 12-11-09 at 05:04 PM. Reason: image not posting
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Old 12-11-09, 05:03 PM
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This may help:
http://forum.doityourself.com/electr...your-post.html

6" walls should be around r=19. On a cold day/evening, an auditor with his/her infrared camera would be able to show you in a few minutes what is in there. Even a fire department with a friendly fireman might have a camera.

Bud
 
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Old 12-11-09, 05:10 PM
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IMG_4710 on Flickr - Photo Sharing!
Thanks.
Local FD is only 2 miles away... hmmm
 
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Old 12-11-09, 05:31 PM
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Originally Posted by fnworks
IMG_4710 on Flickr - Photo Sharing!
Thanks.
Local FD is only 2 miles away... hmmm
Be sure to bring beer with you.
 
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Old 12-11-09, 05:35 PM
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After 20 years that sheathing looks to be in really good shape to me.
 
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Old 12-11-09, 05:35 PM
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I think they know me well enough, lots of burning permits over the last 12 months to get a bigger back yard in the works for the kids.

RE Air sealing. Didn't know that was the term but yeah, cover all that already. Only issue I have is one of the garage doors as a 1/8 - 1/4 inch gap on one side for about 2 feet I can't seem to seal. but the door from the garage to the house is solid so it shouldn't be much of an issue. New garage doors hopefully from Santa in 2 weeks anyway. ;-)
 
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Old 12-11-09, 05:38 PM
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Originally Posted by drooplug
After 20 years that sheathing looks to be in really good shape to me.
really? I'm certainly no pro, and I know if the siding was junk the plywood could "breathe" and dry itself out... but with the window sills rotted... 3 of the 4, I was worried about what was under the plywood. This side of the house sees all the weather too. All but the sun. Don't they say that moss grows on the north side of trees?

you really think that stuff looks OK?
 
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Old 12-11-09, 06:18 PM
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That is my opinion. If the plywood was seeing the same amount of water as the sills, it wouldn't look so clean. Yes, the nails appear to have rusted and there are some vertical stains from that rust, but I don't see any weathering of the plywood. You don't need very much moisture to cause those nails to rust. That also could have happened before the siding ever went on the house.

Just because there was water intrusion at the window doesn't mean that water was finding its way behind all of the siding. Where the siding meets the window is a weak point and the one of the most likely places for a leak.

From what you describe there seems to be an issue with your insulation. I would keep investigating to find out if there is a problem with it, but I don't think the water intrusion was nearly as bad as you had suspected.

Moss does grow on the north side of trees. That's because of the shade, not because it rains more on the north side. The south side is typically the most weather beaten. That is certainly the case with my house. The north side is the nicest.
 
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Old 12-11-09, 06:26 PM
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More reading and advise taken. (And a jault to the boys in red as I went for a DnD Coffee). Though they'd love to help out they can't spare anyone tonight. Advised to go to the local HomeDepot and pick up a RYOBI for $40?...

Anyone use either of these?
Ryobi Thermometer - IR001 at The Home Depot

Ryobi Tek4 4V Professional Infrared Thermometer - RP4030 at The Home Depot

I would tend to go with the more expensive one cuz let's face it, I'm a man and I love my electronic toys. Maybe I could tell wifey to pick it up as an early Xmas gift that will be an invaluable tool as home owners... but she's a pincher too...so... Comes down to functionality.

drooplug, you're right, I wasn't seeing the forrest for the trees. Invetigate further then tackle the problem instead of potentially making a bigger one. Thanks for the fruitful advise.
 
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Old 12-11-09, 06:29 PM
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Is the new siding already going up in that picture? Looks like they weren't putting anything behind the siding.
 
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Old 12-11-09, 06:36 PM
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IMG_4715 on Flickr - Photo Sharing!
and
IMG_4716 on Flickr - Photo Sharing!

hhmmm.. good catch, damn I shoulda been home. While it looks like the did on most of it. The second shot shows they definately did not use anything around the garage doors!

totally off topic but here's a great before shot and the major reason for my concerns that I had watered down insulation issues.
http://www.flickr.com/photos/4549739...60996/sizes/l/
 

Last edited by fnworks; 12-11-09 at 06:43 PM. Reason: added before shot
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Old 12-11-09, 08:20 PM
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They would have used the tyvek throughout. They just started above the garage and went back and filled it later.

Your sheathing looks like boards, not plywood. Some areas may be patched, but not sure. Are you sure it is plywood, 4 foot by 8 foot sheats.

If you pick up an infrared thermometer, they are completely different in function to an infrared camera. All you get with the thermometer is the temp in one spot and if the distance to spot ratio is say 12 to 1, then from 12 feet back you are looking at a one square foot spot. Not very sensitive. Good ones are 20 or 50 to one. Anyway, they are fun, but just seeing the surface temp will make it difficult to identify missing or damaged insulation. There are lots of IR examples on the internet.

Bud
 
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Old 12-12-09, 05:27 AM
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It's definitely plywood. It looks like there was no building paper under the original siding. You can see that in the picture where the old siding started to peel away.

I now understand why you think there is a problem with the insulation. I don't see any problem with the sheathing. Certainly water and/or moisture could have gotten through to affect the insulation. How long was that siding peeled away like that?

Keep investigating. The infrared camera is a good idea. If you don't go that route, try a few small investigative holes in the wall. I know you are trying to avoid that as much as possible, but you will never rest easily until you know for sure.
 
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Old 12-12-09, 11:39 AM
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Make sure you get a warranty with the installation against water intrusion from them. The Tyvek housewrap should have been installed continuously around the corners or the corners folded 4-5 times 2'wide for air and water tightness. Just butted to the corner trim and vinyl butted there is a weak joint. Not really caulkable either due to the different materials. The bottom of the windows may be a problem due to the incorrect application: http://www.napleslumber.com/catalogs/HTyvek-81994.pdf Installing and Flashing Windows Correctly - Fine Homebuilding Article
The plywood looks fine, even with the leftover lines from the horizontal lap siding pressing on the building tarpaper.

If you insulate, closed cell foam is the best though you will need an additional vapor barrier (poly) IF one is required by your local Building Department. Sprayed foam has a permeability rating of 1.8 at 1" thick, to be a vapor barrier, not retarder, it would need to be sprayed 24" thick (.08 perm.)to be impermeable like poly sheeting or foil. At 3-1/2" thick when sprayed at 2#, it has the perm of 0.5, about the same as asphalt faced paper (.4 perm.) on glass batt insulation (vapor retarder- semi-impermeable): http://www.henry.com/fileadmin/pdf/H...l_Brochure.pdf

The Tyvek is an air/water membrane, not a vapor barrier. With an inside v.b. (0.1 or less) any moisure in the cavity dries to the outside, through the plywood (.75 perm.), then theTyvek (85 perm.), and finally the vinyl siding (75 perm.). Be thankful you have plywood, not OSB with a water leak: http://www.rci-online.org/interface/...ton-murphy.pdf

Be safe, Gary
 
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Old 12-13-09, 07:26 AM
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I came across this link that I thought could be helpful. A person in your similar situation did a similar approach to what I suggested and used spray foam to re-insulate.

http://www.sprayfoamdirect.com/appli...trofilling.php
 
 

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