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Help with Insulating my house

Post in 'The Green Room' started by mrfjsf, Oct 28, 2011.

  1. mrfjsf

    mrfjsf Member

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    Hey all, I have a 1930's-40's cape cod with a dormer addition on the rear. Approx 1300 sq/ft. The addition is aluminum siding over wood frame. Im guess the addition was put on 10-15 yrs ago, Maybe later. The original portion of the house is solid brick with backup block and plaster finish. There is only a 1/2" air gap between the plaster and exterior brick so no room for blow in insul.

    Im trying to insulate the best I can with what I have to work with. What im thinking of is stripping the alum siding, putting insulation board over the whole house, moisture barrier, the insulated vinyl siding over everything, brick included.

    Do you all think it would make much of a difference to get the insulated vinyl over regular vinyl? Im sure the cost im substantially higher so I want to be sure it is going to be worth it.

    Im just looking for the best possible way to insulate this house without getting into MAJOR reconstruction. Any suggestions?

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  2. semipro

    semipro Minister of Fire

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    Adding foam board insulation to the outer shell sounds like the way for you to go. You'll find some good info on this at the greenbuildingadvisor and building science websites.

    My understanding of insulated vinyl is that its a waste as air is able to circulate behind it negating any gains Spend the money instead on the insulation and a good, well-sealed infitration barrier under the vinyl.

    Oh yeah, address air infitratin issues in your house before worrying about thermal insulation.
  3. Jack Straw

    Jack Straw Minister of Fire

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    How is your attic or with a cape the ceiling insulation. I am under the understanding that around 80% of the heat loss goes up. I would do some research before I spent that much money. I have read articles that said vinyl replacement windows have about a 20 year payback. I'm not sure doing the brick area is going to help all that much.
  4. midwestcoast

    midwestcoast Minister of Fire

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    I have a 1950 brick cape, but mine's wood frame, brick veneer. I'm all for boosting efficiency, but like Straw, I wonder about the attic situation.
    A couple years ago I blew cellulose into my attic after a lot of research on various building science & home improvement sites. The main take-away from that research was that old homes leak a lot of air & cape styles leak more than most. There are big potential savings from air sealing that are very cheap & must be done first if you're to see much benefit from adding wall insulation.
    Start in the attic as hot air rises up & out. In my attic (common in old Cape's) I found that all the upstairs floor joists were open straight through to the side attics. That means we had unconditioned air flowing between the upstairs floor & ground floor ceiling. I sealed about 20 of those joist bays or approx 17 sq feet! Other major gaps I found were around the plumbing stack and unsealed attic hatch. Smaller leaks were all over as well. When I accessed the 2 larger side-attics I found no insulation at all over the ceilings, just the plasterboard. There was about R-1 balsa wool for insulation on the backside of the knee-walls and over the stairway ceiling.
    I couldn't access the 2 smaller side attics so I just drilled a few 2" holes & blew maybe 3 feet of cellulose in there.
    Another feature of the cape-style homes is relatively little exterior wall area since the sloped roof serves as exterior walls on the long sides of the upper floor. Another reason why attic insulation is very important.

    After the attic, look at air sealing in the basement as that's where cool air is drawn in the most. Insulate the rim joist well & consider insulating basement walls, especially those parts that are at or above ground level.
    Air seal the ground & 2'nd floors including fixing-up drafty doors & windows.

    All that stuff will have a very short payback & should cut your energy consuption significantly.
    Only THEN consider adding exterior wall insulation & siding. It's a much bigger job & is gonna have a longer payback. Read a lot about it on building science sites before jumping in.
    If you do it I'd go for the thickest foam possible & as Semipro said don't count on any foam on the vinyl for insulation as air will flow behind it anyway. Also think about how much work & cost might be involved in building out all your window & door frames out past the new foam & siding.
  5. woodgeek

    woodgeek Minister of Fire

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    While I am a big fan of attic/rim airsealing and insulation, the OP has NO insulation in any of his walls! He should do the attic first as described above (faster payback), but I think he will still want to insulated the exterior eventually. He could do the Dormer first....he might also look at insulating from the interior with foam to keep the brick exterior. A lot of brick construction in the UK is being retrofitted--you might research what they do....
  6. btuser

    btuser Minister of Fire

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    I think you're nutz to cover up brick if its in good shape. Definately a good tip to insulate from the inside out.

    That also sounds like a hell of a lot of work for any potential gain. Get a good heat loss calculator and then figure out what your payback period would be. Through-wall heat loss is right around 10% in typical construction (if you go to r100 in the attic, this number will get skewed but its a good place to start) so you'd do the most good by sealing around any penetrations, sills and the like before you start adding r2-r7 of foam board to the outside of your house. I've thought about it and costed out with my house and it would be cheaper/easier for me to rip down the inside walls and sprayfoam than it would be to insulate/reside from the outside.

    Unless I was trying to tackle an exterior aesthetic issue at the same time I would exhaust every opportunity/option before I tried this.

    Edit:

    I just re-read your post. What is the exact construction of the walls in your house? by back-up block do you mean brick/cinder block/strapping then plaster? What is the thickness of your walls? If cinder block are the blocks filled with vermiculite/foam beads? That would give you about r7-r10 which is a lot better than nothing, but depends on sealing the top plate to keep air movement to a minimum.

    Sounds like a cute little brick house. Wanna trade?
  7. mrfjsf

    mrfjsf Member

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    Thanks for the tips all!

    By siding the whole house, I would be addressing aesthetic (sp?) issues as well as insulating. The aluminum siding on the dormer is in poor shape, as are my gutters, downspouts, soffit, fascia, etc etc. Not to mention, the previous owner painted over all the brick grrrr :(

    The side attic/crawlspace on the rear of the house was eliminated with the dormer. The front is still in-tact and I believe has R-12 or 15 between the joists. ( I thought about upgrading this to the highest R-Value batt I can find or should I blow in?) The attic, or lack there-of is insulated, im not sure of the R-value as I have no attic access. When the upstairs/dormer was added by the previous owner, they never left access to it. I thought about adding attic access and blowing in cellulose to help. Im guessing the insulation that is in there is not all that great because in the summer it is STUPID hot upstairs. I do believe there is insul between the rafters up to where the attic begins, once again, not sure of the R-Value

    The exterior construction is as follows. Solid block (4"x4"x8" I believe), then some sort of hollow brick (can't describe the shape but they are strange looking, I know they are about 2" thick), then plaster directly over the hollow brick.

    Insulating on the inside walls is out of the question, my rooms are small enough as it is and I dont want to ruin the appearance of the original plaster.
  8. dougstove

    dougstove Member

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    If you insulate the outside you could incorporate all that brick & block into the thermal mass of the wall, and it might give a significant buffering effect for solar gain or woodstove space heater output.
  9. mrfjsf

    mrfjsf Member

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    This is my thought. Once the brick gets cold, it takes forever to heat the house up, its constantly fighting against itself. But once I get the hearth room hot, I can actually melt a 6" perimeter of snow from around my foundation. Im hoping the insulation board will help keep some of that heat in.
  10. smokinj

    smokinj Minister of Fire

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    If your melting 6 foot you have a very leaky craw space.
  11. mrfjsf

    mrfjsf Member

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    6 inches
  12. barkeatr

    barkeatr Member

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    i would not install siding over brick. your brick most likely has an air drainage cavity behind it and you dont want to block that and any insulation on the cold side of a masonry veneer is going to be ineffective unless you somehow totally seal up that masonry cavity....anyway..dont cover brick it adds great value to your home. you wont be able to use the brick thermal mass effectivly if you try to insulate the outside and bring the brick mass inside the envelope because the original building insulation will block thermal flow to it. again, there is most likely an airspace between the brick and the insulated wall so the brick is not really making the home colder....

    insulated vinly siding will not add to your total r value of the wall. siding is generally thought of being on the outside of the thermal envelope.
  13. GaryGary

    GaryGary Feeling the Heat

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    Hi,
    If the brick wall faces south, you could think about glazing over it with something like SunTuf polycarbonate glazing. This can be set off the brick with spacers. It makes the brick wall act a little like a Trombe wall, and it increases the night time insulation a bit. You would still get the look of the brick through the glazing. It costs about $1.25 a sqft.
    http://www.builditsolar.com/Projects/SpaceHeating/nicksthrombe.htm


    If you want an idea where the best payoff might be, you can get an idea how much is going out walls, ceiling, windows, ... using this calculator:
    http://www.builditsolar.com/References/Calculators/HeatLoss/HeatLoss.htm
    Its easy to use, but you do need to find out what your current insulation levels are.

    Gary
  14. mrfjsf

    mrfjsf Member

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    Not sure how siding over my brick will bring the value of the house down. If the brick was original finish, i.e not painted over, then yes I can see why siding over it could degrade the home's value. However, its not. The brick is painted over with a crappy paint that is peeling, certain spots need repointing, etc.

    I would think by adding an easy to maintain, good quality vinyl siding, it would actually increase the value of the house.

    On the attic, I was looking at lowes today and saw that they rent blown insulation machines. I looked at the bag of insulation and it said with 16" thickness I can yield an R-60. Does that sound right or is there better insulation out there. Also, I was in the front portion of the attic today and saw that portion of the attic is insulated with R-11. The back wall of my bedroom is in that portion of the attic and there is no insulation on that wall so im thinking by adding some insulation to that back portion of the wall should help a little as well because it was pretty darn cold in that part of the attic this morning.

    I can add attic access and blow in for an R-60 on the peak portion of the attic and the front portion of the attic, but, what do I do about the portion that I cant get to, such as the ceilings upstairs where the drywall is butted up against the rafters with the R-11 behind it? If I cant rip it out somehow, will me adding blown in to the upper portion help?
  15. barkeatr

    barkeatr Member

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    i only read your original message, missed any comments about the brick being painted. thats not so good...maybe covering it makes more sense. cellulose is good insulation it tends to seal air flow better than fiberglass. any additional r value will help, it does not have to be througout to count. good luck!
  16. mrfjsf

    mrfjsf Member

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    Thanks, ill at least start with that. If I can rip out the R-11 between the ceiling plaster and the rafters and blow in-between and down them, then I will, otherwise just the peak attic will have to do.
  17. jharkin

    jharkin Minister of Fire

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    There is a book called "insulate and weatherize" by Bruce Harley. Highly recommended reading before you make any decisions. Also check out buildingscience.com and maybe post this question over at oldhouseweb.com.

    Remember that insulation levels are relative. Going from nothing to as little as R10 will make an enourmous difference. the same 10 point jump from R30 to R40 would not even be noticeable unless the rest of the house was super tight and super insulated. Concentrate on the air sealing and uninsulated areas first, then work on upgrading the parts that are insulated.

    Check around to see if there are any subsided energy audit/weatherization programs you might be eligible for.

    Finally, and this is just MHO I have to say I'm not a fan of vinyl anything, and would vote for keeping the brick. You can have it media blasted to take off the paint.
  18. DBoon

    DBoon Minister of Fire

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    It doesn't sound like there is any easy solution here....

    But if the brick is really in bad shape, is painted over, and needs re-pointing (which I know can be pretty expensive - $7k per side, perhaps, depending on the area), why not consider dismantling the brick and rebuilding a new heavily insulated wall over the block substructure? I know that I'll get lacerated by others for suggesting that (I am a big proponent myself of preserving old house details), but fixing the brick is going to be costly, and simply covering it up may not be the wisest move either if it is structurally unsound (i.e. needs repointing) or has a drainage cavity between the brick and the sub block.
  19. midwestcoast

    midwestcoast Minister of Fire

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    Sounds like you're getting on the right track with the attic. Yes, insulating the backs of walls btw the living space and the side attics (called knee-walls) is important. You want to seal those side attics off just like you would an exterior wall. The sloped portion where the ceiling meets the roof rafters can be tough. It depends on how much access you can get to those areas. If the R-11 looks to be in good shape & well installed and the area is hard to get at, you may be better leaving it alone. If you can reach those spots from the attic and/or side attic you can pull out the R-11 and replace it with layers of rigid foam board cut & pushed in to fit snug with the rafters. Doing a half-a$$ed job of that leaving gaps is probably worse than leaving as-is though. You want an air-space between your insulation and the roof decking, that keeps your roof from overheating in summer so DON'T fill the rafter bays up with cellulose (assuming your roof is shingled here).
    In the side attic you accessed were the joist bays open to the underside of your floor? If so you really need to seal them up. rigid foam & spray foam is good, or a plastic bag stuffed tight with fiberglass will do for quick & dirty.
    TRy to get acces to all side attics if possible. I cut a hole in a downstairs closet ceiling to get to one for example.
  20. midwestcoast

    midwestcoast Minister of Fire

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    While you're poking around up there can you find out how much insulation is over the ceiling of the dormer addition? That could change the equation here too.

    Have you considered getting a good energy audit to give a whole-house evaluation & help you prioritize this work? Might be money well spent before going at it one piece at a time.
  21. mrfjsf

    mrfjsf Member

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    WHen I re-did my ridge vent this summer I saw that it was insulated, im assuming fiberglass batts probably R-11 like everything else. Im thinking of cutting access to that area in my ceiling upstairs, and blowing cellulose overtop the fiberglass to yield around a R-60 or better. Like I said before it gets UNREASONABLY hot upstairs in the summer and believe it or not, colder in the winter than the downstairs is.
  22. mrfjsf

    mrfjsf Member

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    I know we talk alot here about air sealing, my question is; what areas are do's and dont's for caulking and sealing? I know around windows is a must, all of my windows are sealed, are there other areas I need to address? areas not to seal up?
  23. jimbom

    jimbom Combustion Analyzer

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    Establish a boundary in your mind. Mine is every interior paint and flooring surface of my living space and basement. I took each wall and ceiling individually. Working one at a time, I sealed every penetration to the paint boundary. Room by room until every paint boundary was intact. Then I went into the basement and attic and sealed every pipe, wire, and gap I could find. This is also a good time to hit the tops of the electrical boxes in the attic. You will only need a few cans of foam to do this. Go around the exterior and seal all the obvious openings for pipes, wires, and boxes.

    After that, take an IR thermometer this winter and identify any interior cold spots. Try to identify the reason. Most of the time a spot of colder wall will be some sort of infiltration. If not, put that spot on the to do insulation list.

    When your house is very tight, infiltration at the windows and doors may become more apparent. Fix those.

    Monitor things for a winter while you read the information on the net from sites like http://www.buildingscience.com/index_html Then you will have an idea of the various approaches to insulate your house.
  24. barkeatr

    barkeatr Member

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    Go to the site Fine Homebuilding and type in energy fixes or some such...they have some Great articles on this. Band joists are a biggy..
  25. jharkin

    jharkin Minister of Fire

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