Insulating old house

Discussion in 'Remodel Forum & Blog' started by Master Brian, Jan 9, 2009.

  1. Master Brian

    Master Brian DIY Senior Member

    Messages:
    368
    Location:
    Kansas
    I have a 1915 Craftsman style Bungalow with clapboard siding. I know the walls aren't insulated well/if at all. I am also pretty sure there is no sheeting under the siding, as when I went to drill a hole for a bathroom vent, it was siding then empty wall spac.

    I am going to be doing a paint job this spring on the outside of the house and have a few thoughts....

    I am pretty sure I can pull one or two rows of siding off in a few areas to get access to the inside of the walls and if not, I am thinking I can take my 2" hole saw and just drill holes at every cavity, then replace the plug, fill and sand. The 1st method would be the cleanest and quickest if it works like I think it will, but I know I can do the 2nd method.

    My questions are what type of insulation should I blow into the walls? I still have the lath and plaster and don't want to create any issues with it. I have thought and read about the foam, but think it might be too risky and expensive. At this point, anything is better than the dead air space I have as insulation now.
  2. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

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    22,134
    Location:
    New England
    My thoughts...without a vapor barrier, you risk rotting the structure if you use something like cellulose. A closed-celled foam might qualify as a vapor barrier - you'd have to check carefully.
  3. Master Brian

    Master Brian DIY Senior Member

    Messages:
    368
    Location:
    Kansas
    Can you explain?
  4. Master Brian

    Master Brian DIY Senior Member

    Messages:
    368
    Location:
    Kansas
    When I ask to explain, maybe I should clarify...

    I understand the vapor barrier keeps moisture and such at bay, but I thought cellulose was good at combating mold. I'm sure the spray foam is out of the question do to cost and the fact, I probably won't/can't do it myself due to lack of tools for that job.

    I guess I hadn't thought of the vapor barrier angle as I've just heard and seen of others doing this often. How do you get around the vapor barrier and/or how do you determine if it's needed?
  5. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,134
    Location:
    New England
    Insulation moves your dew point (the point where condensation occurs), and without a vapor barrier, it could end up inside of the wall. Cellulose doesn't allow air movement much if installed properly so that helps, but if the cellulose gets wet from condensation, it will take forever to dry out. It might not mold, but the wood, can.

    There are companies that sell spray foam in large kits in various configurations that are much more ecconomical than little cans and maybe a contractor doing it. It can be a messy job, and you need to be careful not to put in too much, or you can split walls, break windows, bow walls. But if you follow the instructions and pick the proper foam to do it, you shouldn't have problems.
  6. frenchie

    frenchie Jack of all trades

    Aside from the vapor-barrier - what about a weather-resitive barrier?

    If there's no sheathing, and you have any leaks in the siding... right now, water gets in but also gets out, and there's possibly enough airflow to dry things out. But if you stuff the cavity with insulation, especially a non-waterproof insulation like cellulose... your house will rot.

    The right foam for this situation is poured, not sprayed, and it's pretty expensive. And if there's no WRB, or if the WRB is degraded, you'll still have moisture coming in via the studs; more to the point, you'll be effectively glueing the siding on, good luck with any repairs later on.

    Sorry, but the only really correct approach, is to pull the siding completely. Insulate, sheath, wrap, and re-side.
  7. pmoe

    pmoe New Member

    Messages:
    25
    Location:
    Norwood OH
    Keep in mind there is more than one kind of foam. There are expanding (looks like shaving cream) and non-expanding foams. Within the expanding category, there are open and closed cell varieties.

    If you're worried about blowing the plaster and lathe, you can use the non-expanding variety, e.g.:

    http://retrofoam.com/
    http://www.usainsulation.net/

    Expanding:

    http://www.demilecusa.com/
    http://www.icynene.com/
    http://www.emegabuild.com/

    DIY kits:

    http://www.tigerfoam.com/

    FWIW, I used expanding foam (Demilec) on plaster and lathe in my finished attic, and only had a problem over one window. I figured that plaster would have needed repair anyway, so I'll just put up some blueboard and get it skimmed when the rest of the room is finished.

    I didn't have any problems with the underside of my roof deck blowing out any plaster. An experienced insulation contractor should be able to advise you. I certainly wouldn't discount it before talking to someone who has experience in retrofitting insulation. You may very well be fine.
  8. Master Brian

    Master Brian DIY Senior Member

    Messages:
    368
    Location:
    Kansas
    Frenchie, You are probably correct about the leaks, I had thought about that. I haven't decided what I am doing yet, but I will say, when I paint, there won't be any gaps/cracks anywhere I touch. I plan on using expanding foam spray and 50yr caulking throughout. With that said, I realize there is always the potential for a shift or crack to occur that I miss.

    I don't see any future concerns regarding "glueing" the siding on with an expanding foam, as this is the original clapboard siding and I don't ever plan on replacing it!

    I also checked on a few of the foam products and haven't found any dealers in my area, but I may call them next week and see what they say.

    Tearing the siding off is a thought. I just wonder how much work/trouble it would be furring the windows and such out to account for sheating. Hmm... Siding in and of itself doesn't scare me one bit, as I used to be a siding sub on new construction for a few years. Problem is I've never messed with the clapboard much and I want to keep this original siding.

    Let me ask this, is there some wrap that I could possibly use in place of using sheeting? I know sheeting would be preferred, but.......

    If I pull the siding off, should I just install fiberglass batting? I know the sprays might be more efficient, but I am not easily convinced all of that type of stuff is really worth the added cost. I'm sure not paying someone $10k+/- to insulate my house. The other thing I worry about is getting this house too tight and causing issues. These old houses are designed to breathe.

    Thanks for the things to ponder....
  9. frenchie

    frenchie Jack of all trades

    Even if the foam means it starts rotting?

    Google "pour foam".

    Yes, you could then use fiberglass, or cellulose... Would the savings, from not using foam, cover the extra hassle? Not sure.

    As for sheathing - house that old probably has left-in bracing for racking/sheer resistance, so it's not absolutely necessary. Probably ok with just housewrap. It's been there for awhile, right? And it's still fine?

    If you open up the walls & there's no bracing, though... I dunno.

    Mind you, if you don't add sheathing, you'll have to be extra-careful with flashing, because it's one less backup drainage plane. And must tape every seam, because it's also your air-seal, now. FG is useless if there's air movement, it's just a big air filter then.

    You're right that the old walls are designed to breathe - they work by a very different process than modern walls. The old walls let water in, but also let it out again; and they have plenty of airflow (drafts) to make sure things dry out, later. That's why it gets complicated when you insulate them. It's easy to cause a disaster. You stick insulation in there, now there's something that holds water if it gets damp.

    So your water-management details have to be tighter, and you have to seal up the drafts, to prevent moisture-laden air getting in & condensing inside the wall. But by doing that you're also making it harder for any moisture that does get in, to dry out... The worst outcome is when you try to compromise between new & old approaches. An insulated wall that leaks, doesn't last long.

    A lot to think about, for sure.
    Last edited: Jan 12, 2009
  10. Master Brian

    Master Brian DIY Senior Member

    Messages:
    368
    Location:
    Kansas
    You are correct, there is a lot to think about. The worst part is for every question, there are a dozen different answers!

    No, the foam is not good if it gets wet and the wood rots out. I do think, at least to some extent, that if I at least stay on top of the exterior maintenance, any rotting should be kept to a minimum. It would be one thing, if it sat and sat and sat in damp conditions for years, but, if you can catch the issue, that "should" buy some time. That theory probably works best when dealing with rain and such. The condensation is another thing all together and a real concern, because my windows ice up badly in the really cold weather!

    I have googled pour foam before, but will do it again. I know there are some DIY kits, but they just seem really, really expensive. My average utitlity bill is probably $250-$300, for this 1-1/2 story, 1900 sq ft house with about 700sq ft of unfinished basement. I know that is not good by any stretch compared to today's newer houses, but it is what it is on these old houses. In fact my previous house was 1300sq ft and 1-1/2 story and it cost me about $25 per month more for utilities! My point is, it would take 10+ years to justify spending ~$10k on having someone insulate the house correctly. I just am not certainit's worth that.

    I also know from experience, with watercraft, with two part foams, they do tend to get waterlogged over time. I suppose one solution which wouldn't provide excellent R value, would be to use 2" rigged foam panels, cut to size and inserted into the walls. With that, I would then leave a little "air chamber" as well throughout he outside of the wall, which would allow the wall to still breathe! Thoughts?
  11. Scuba_Dave

    Scuba_Dave Extreme DIY Homeowner

    Messages:
    885
    Location:
    South of Boston, MA
    I went thru similar problems with my old house - 1905
    Luckily it had sheathing & tar paper
    The inside was a mess so I gutted room by room on the inside & insulated

    The problem I see with the rigid foam boards are they have to be tight
    If you have any gaps it will let air flow in
    That said any insulation is better then none, but better to do it right the 1st time. My kitchen was cold & drafty before, after it was nice & warm.
    I was heating with wood - open floor plan, so it cut down on the amount of wood I went thru

    Is your basement "warm" ? I had single pane windows & a door that did not shut right. New door, new windows, insulated the sill plate all the way around. Basement went from 45 the 1st year to now around 58-63 depending upon outside temps

    How old are your windows? As purchased our house had vinyl replacement windows, But they never took out the sash weights & insulated the cavities. I spent maybe $4500 on new windows, I have since saved that money in reduced heating costs. An added bonus is the house is much quieter
  12. Master Brian

    Master Brian DIY Senior Member

    Messages:
    368
    Location:
    Kansas
    There is always a chance, there is something on a different wall, but where I drilled through had nothing. Hmmm....

    If I did the rigid foam, I think I would lightly push the panels against the plaster wall. As long as it isn't tight, it shouldn't hurt the lathe and it would allow some air movement. I would then use gap and crack spray foam to seal the panels to the studs. This would not only keep it in place, but stop drafts. I would also then have about 1" of dead air space between the outside wall and the panel, which should allow sufficient air movement to keep things dry. That is my thoughts in any case, not sure how it would work in the real world. I am not overtly impressed by the R value of the foam. 2" foam seems to be 7.8 R value. I'm sure if I foamed the edges, it would go up and again, it is better than what I have now and shouldn't rot anything out.

    Basement is ok, it gets a little chilly, but there again nothing is insulated. I am going to be going in and sticking something in the cavities along the sill plate. I am also going to most likely insulate the ceiling with at least 3-1/2" fiberglass batting. This is only to stop sound as I will be turning my basement into a game/tv room.

    Windows all appear to be original and I'm not changing them. I currently have some wood storm windows, which I plan on making/installing on all windows and some aluminum storm windows on some. Most windows have nothing on the outside and most probably need re-glazed. I have read through several sites that the old windows, when rebuilt and maintained are just as efficient as current windows, except they have a much longer life span. I will probably eventually get to the sash weights and either rework them, per "This Old House" and insulate them, or remove the weights and use the "Sash Springs", which work similar to a tape measure thus freeing up that cavity to be insulated fully.
  13. Scuba_Dave

    Scuba_Dave Extreme DIY Homeowner

    Messages:
    885
    Location:
    South of Boston, MA
    If you are going to seal the rigid boards then that would work
    Just be careful about codes & renovation. I know someone who was renovating a house in a cold climate & the building dept stepped in & said they would have to meet current insulation codes, His intent was to sell the house, so that was the main reason I believe

    I can see wanting to keep the look with a 1915 Craftsman
    My old house was just a cottage that had been partially updated
    My current house has R7 insulation, 3/4 sheathing, & thick old wallboard with a heavy plaster (?) finish. It does very well on heat, but every window I had to custom cut the trim

    The windows & doors made the most improvement in my basement
    But insulating the sill plate also helped - I could feel the cold/cold air
    I went around with a caulking gun & sealed everywhere I felt cold air
    Insulating where the sash weights are was another major improvement

    With the garage addition, sunroom, greenhouse, 3 season front porch, & a new 6" wall in the front I have added additional insulated areas around the old walls of my house. If I ever get "caught up" I will take down the wall board from the inside, remove the R7 on 2 rooms & insulate them with R15. The rest of the house is OK with the additions

    I've learned over the years its better to do things right the 1st time
    In some cases I made Temp fixes until I could do what I wanted
  14. Master Brian

    Master Brian DIY Senior Member

    Messages:
    368
    Location:
    Kansas
    Doing things right the first time is what I want to do as well. The hard part is it normally requires starting 5 other jobs, just to complete the one....

    Nothing worse than later regretting the job. To be honest, if I have to go through the work of pulling off all the siding, I probably won't do anything. A friend of mine is a contractor and he seems to think blowing the cellulose in would be fine as well. Of course, he is used to new houses and thinks I am crazy for wanting one of these old ones. Everyone has their opinions.

    On another note, I wonder how much R value this old lathe and plaster has compared to sheetrock.....
  15. Master Brian

    Master Brian DIY Senior Member

    Messages:
    368
    Location:
    Kansas
    Ok, well I called by Owens Corning and GreenFiber. Both said I shouldn't have any issues with their blow in material IF my siding is in good shape. They said moisture shouldn't pose any problems.

    Owens Corning was a professionally installed product, GreenFiber can be purchased at Lowes and HD, so that is the option I would choose.

    I guess my last question is how do you determine if/when moisture might be a problem? They did ask me where I lived....
  16. frenchie

    frenchie Jack of all trades

    You're a natural! We were just talking about that approach, in a carpenter's forum the other day. You'll have to wade through a really stupid argument in the middle, but the rest of the thread is worth reading:

    http://forums.jlconline.com/forums/showthread.php?t=45436&highlight=cabin
    [Standard warning: that site is adamantly pro-only. There's a lot of good information there, and if you register it makes searching easier (no image verification thingy), and lets you download attachments. And anybody can register, but only people who build or fix houses for a living are allowed to post. JLC members can be really mean, nasty, rude and/or obnoxious bullies when enforcing that rule. You have been warned...]

    That thread is about doing it from the inside, but same basic idea. You definitely need to find a way to drain the cavity, somehow (occurred to me later: you could just scarf the front of the bottom plate). And remember to bug-net the openings...

    Worth it to spray the edges, like Dave said. Air-sealing's critical.


    But they would, wouldn't they? :) ...seriously, though, it might be fine. To a certain extent, blown-in can dry through the wall, same as the cavity does now.

    The possible problem is that because you've insulated, the cavity's a lot cooler than it used to be (in jargon, you've changed the hygrothermic balance of the assembly). Basically, less warmth = less evaporation... So there's a risk.

    It might be okay, it might cause problems. Depends on the specifics of your house, how much air leakage there is, etc.

    Moisture meter. Check the wall cavity before/during/after a bit of rain.

    Or: open a wall somewhere, just enough to take a peek. Look for drip-marks on the backside of your siding, especially around & below windows, etc.

    If you mean after insulating - the first sign of moisture issues, usually, is peeling paint on the siding.
    Last edited: Jan 13, 2009
  17. Master Brian

    Master Brian DIY Senior Member

    Messages:
    368
    Location:
    Kansas
    Thanks for the link, problem is they also talk about doing it from inside out, taking one side of the wall apart. I wouldn't mind doing that, IF the siding pulls off ok, but something tells me that isn't going to be the case with 100yr wood and nails. Working one or two rows all around the house is one thing, working every board is another.

    Yes, I would suppose the two companies would say that, but then again, sometimes people are actually honest and would say, no this is not what you would want.

    I also checked with the Dept of Energy's website and it look like they seem to say in my area a vapor barrior isn't a necessity. I plan on trying to call my local inspection office and/or the states DOE and see what I come up with.

    Another thought, I just had was there is an upstairs bathroom, which has been remoded since probably the 80's. I believe it has fiberglass batting behind drywall. Being as I plan on remodeling this bathroom in the near future, maybe I'll cut a hole in the wall and see what is going on. If it is dry with no real signs of water that has sat, maybe I'll be ok. It's probably the best answer to my question.

    My lingering question here is how much different does air flow around fiberglass batting vs. blown in cellulose? I would think the cellulose would be a tighter "pack" thereby not drying as much; however, I tend to read that cellulose is better at absorbing and distributing the moisture. Hmmm..

    Another thing I am wondering about is a two-fold approach, much like is discussed on the other board. What if, I was to remove the bottom 1' of siding, intall some foam panels about 1' high in such a manner as to create a stop, so that the cellulose wouldn't be allowed to settle at the bottom of the wall. My thought is I woul get good fill for 99% of wall, but if any moisture did accumulate, it could settle, via gravity, towards the bottom of the wall and then mitigate out the wall. I have attached a crude drawing.... Only problem is, this might put too much water on the bottom plate....

    Attached Files:

  18. Chessiec

    Chessiec New Member

    Messages:
    23
    Location:
    durham, nc
    Assume moisture will get into walls, whatever you do. It is a when, not an if.

    That was the learning from the EIS "stucco" system and all the lawsuits that resulted when relatively new homes rotted from the inside out, and more quickly than would ever be expected.

    The drainage plane idea is key.

    The headaches of insulating the walls right is such an expensive bother, I would make sure that all of the higher priorities of energy efficiency have been done first.
    #1. Attic, including plugging all joints/gaps which create convective loops, then insulating it to the max. And don't forget to do effective sealing and insulating of all attic access points.

    #2. Plug up the fireplace, if any, either permanently or by using a fireplace 'pillow' plug. Or plug by doing to a direct vent device.

    #3. basement, crawl space insulation. If no water infiltration from exterior, go to a closed crawl space. Check out the great information at the Advanced Energy Corp. website on closed crawl spaces. If you are not sure that the grading of the lot, etc. keeps water away from the crawl space, insulate the floor instead of using the closed crawl system.

    Of course, plug up any gaps and cracks in the exterior shell, and put insulating foam gaskets in any interior electrical outlets located on the exterior walls.

    After that, I would weigh whether the windows or exerior walls were of higher priority. In part, this depends on how tight or leaky your window frames are. But no way does the building science support that old windows are near as energy efficient as decent, current dual pane windows. In my own home, b. 1948, I have 20 old windows, most of them large. They test reasonably tight in a blower door test. But I don't kid myself that they are near as good as decent new ones.

    (FWIW, my background is having developed an extremely energy efficient neighborhood. I have rehabbed three houses. But I'm no expert on energy efficient rehabbing. For specific info on how to do the insulation if you move ahead, some of the prior advice sounds pretty nuts-and-boltsy.)
  19. Master Brian

    Master Brian DIY Senior Member

    Messages:
    368
    Location:
    Kansas
    I am working towards everything else you have mentioned.

    I hope you aren't saying that possibly replacing my windows with new units at a likely cost of $25000, is a better bet than spending $1000 on blown in insulation.

    I think I just read yesterday on the Dept of Energy's website that single pane glass has an energy efficiency of maybe 65-70 and tripple pane maybe 85. Now I don't know how to exactly figure that, but I am pretty sure it wouldn't cut my energy bill in half, but for fun, let's say it would. I spend about $200 during the extreme months to heat or cool my house, that doesn't include other energy/gas uses. If it cut it in half that is $1200 per year. I have about 38 windows. New "energy efficient" units would run me about $500-$1000 per unit on up. For fun, let' say $750 each. I have some very large windows! 38 X $750 = $28,500. Let's now take $28,500 / $1200 = 23.75 years to break even. The life span of a new window is 15-30 years. I would bet that if I bought the 30 year window, it would cost about double and they'd have to be professionally installed to get the gaurantee and I seriously doubt my bill would be cut in half, maybe cut down $50 p/m at most. So with any way I figure it, it would take me more time to pay off the windows than I would ever save. In fact, before they could be paid off, I would be replacing them. How is that efficient?

    I do want to slightly appologize for the rant, but I am tired of telling me I should replace my windows and get something more energy efficient. My windows do need work, but I can glaze and install storm windows far easier and cheaper than I can replace windows and I'll probably see that payback long before they need it again. These windows will also still be around in another 100yrs unlike the newer versions which will be worn out in a fraction of that time!

    I can totally see energy efficiency on new homes, it's the right thing to do and doesn't cost that much more, but just because it is labeled as energy efficient doesn't automatically make it the correct thing to do for the environment as a whole!
  20. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,134
    Location:
    New England
    If there's a lot of air leaking, fiberglass will just act like a filter. It only works properly in dead air. Blown in cellulose, when installed properly, is much more dense.
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