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additional external walls / double vapor barrier / what to do?

additional external walls / double vapor barrier / what to do?

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  #1  
Old 01-23-06, 09:23 PM
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Join Date: Mar 2003
Location: northern wis./upper mich.
Posts: 16
Cool additional external walls / double vapor barrier / what to do?

i need some good advice on this project! i'm framing in 2x4 sleeper walls flush up to my external living room walls from the inside. i'm doing this for an additional r-13 insulation value, outlets & wall lights. the U.P. of Michigan is unforgiving most winters. here's my problem, when i insulate and vapor barrier my new sleeper walls, what do i do to the old existing walls so they will breathe thru. they consist of latte & plaster / with 2-3 layers of wallpaper. that effectivley makes a vapor barrier halfway thru the 8'' thick double walls. do i drill a ####load of holes in the original existing walls so no moisture gets trapped??? the original existing walls were pumped full with loose fill {blow in} cellulose 7-8 yrs. ago. and no i don't want to knock the old plaster off so it can breathe thru the latte boards. any ideas greatly appreciated. i've talked to a few local carpenters about this but did'nt get a clear cut solution. this 120 yr. old house thanks you for any ideas!
 
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  #2  
Old 01-24-06, 08:08 AM
doug thomas's Avatar
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Location: Detroit, Michigan
Posts: 104
The biggest problem here is that someone has convinced you that your house needs more insulation.

In reality, there is a 99% chance that you have enough insulation. The main problem with your home is that you have too much stack effect through the roof, and it is drawing in cold air through your walls to replace it.

Any home energy auditor who inspects your house will make these recommendations: air seal your ceiling, and then air seal the walls.

The ceiling you can either caulk all the joints and gaps, or you can sweep your insulation up, put down a thin spray foam layer, and sweep the existing back on top.

The walls you'll want to caulk the top & bottom, and corners.

Any comments guys?
 
  #3  
Old 01-24-06, 12:00 PM
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Join Date: Mar 2003
Location: northern wis./upper mich.
Posts: 16
more insulation is always a good thing to add when possible. i just finished 500 sq. ft. of living room ceilings. unfaced r-19 insulation for sound dampening, shimmed, furred, drywall, finished., i also ran miles of cables to all rooms in the house, ethernet, phone/data, sattelite, and extra cables before i did the ceilings. now these sleeper walls give me 3 things. additional r-13 value, locations for about 20 outlets, 8 wall lights, 10-12 dimmer switches for recessed,wall,chandelier, ceiling fans/lights., and a good smooth wall application. my existing walls are bowed in and out in areas. the ceilings we're a huge shimming project, joists bowed running both directions, but is was worth it. it's all about the finished look. i'
m still not sure what i need to do about the double vapor barrier issue. anybody? ideas?
 
  #4  
Old 01-25-06, 11:05 AM
andy2's Avatar
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Join Date: Jul 2005
Location: Ottawa
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Originally Posted by workingman
i need some good advice on this project! i'm framing in 2x4 sleeper walls flush up to my external living room walls from the inside. i'm doing this for an additional r-13 insulation value, outlets & wall lights. the U.P. of Michigan is unforgiving most winters. here's my problem, when i insulate and vapor barrier my new sleeper walls, what do i do to the old existing walls so they will breathe thru. they consist of latte & plaster / with 2-3 layers of wallpaper. that effectivley makes a vapor barrier halfway thru the 8'' thick double walls. do i drill a ####load of holes in the original existing walls so no moisture gets trapped??? the original existing walls were pumped full with loose fill {blow in} cellulose 7-8 yrs. ago. and no i don't want to knock the old plaster off so it can breathe thru the latte boards. any ideas greatly appreciated. i've talked to a few local carpenters about this but did'nt get a clear cut solution. this 120 yr. old house thanks you for any ideas!
I didn't think wall paper could act as a vapour barrier! I would check with a building supplier or contractor about wall paper and if it can act as a vapour barrier.

If you continue with your project and wall paper does act as a vapour barrier; you may want to remove the wall paper or slash it.

First though, check for and seal air leaks and openings/penetrations in the house. You'll be amazed at how many penetrations there are in older homes. This will make your home more air tight as well as block entrances by rodents.

Andy
 
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