Replies

1. 
   Guest_ | May 22, 1999 07:17am | #1

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   Jim

   Not that this will answer the efflorescence question but if you proceed, try using foil faced polyisocyanurate for increased R value.

   -pm

1. 
   Guest_ | May 22, 1999 08:14am | #2

   *Gentlemen, This does not really answer Jim's question, but I dont't see how effloresence can be caused in this situation. As I understand effloresence, it occurs when minerals in the masonary are drawn to the surface by evaporating water. Jim's insulation would not introduce any new moisture. Also, the minerals in masonary eventually exhaust themselves over time eliminating the situation. I am no expert on masonary and I would like to hear from someone more knowledgeable about effloresence.

2. 
   jim_eaton | May 24, 1999 02:48am | #3

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   Dear Fred

   Thanks for your comments. I don't know what the Neutral Pressure Plan of my building is, let alone what it means. However, your statement about possibly trapping moisture between the insulation and brick is something I suspected could happen and don't want to. I do know that bricks will pass heavy amounts of moisture and with that their natural salts creating efflorescence (come visit my basement). This is something I don't care to risk for the sake of what little energy costs 3/4" foam might save me.

   Thanks again.

   Jim

3. 
   Guest_ | May 24, 1999 03:20am | #4

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   Jim,

   It seems we are over looking the "VDR" (vapor diffusion retardant), or formally know as a vapor barrier in your situation. The general consensus here is that the use of common drywall taped with two coats of latex paint should do the trick (cough) this should prevent moisture from getting behind the foam.

   In an effort to make weather tight your wall you will also need to do some work on the outside as well as on the inside. You would need to make sure no air or moisture can get in form cracks of holes in the masonry, pointing would be a good choice, if so required, only a careful inspection can determine this. Patrick's suggestion is also a good choice.

   The NPP (Neutral Pressure Plan) is that magical place in your home where the inside air pressure is equal to the outside air pressure. You can search the archives for more on the subject.

   Joseph Fusco

   View Image

1. 
   Guest_ | May 24, 1999 03:24am | #6

   *JimYou might consider an additional layer of foam i overthe nailers, sealed with foil tape if using foil faced polyiso, adding R value, and moisture sealing if done carefully and precisely.-pm

4. 
   jim_eaton | May 24, 1999 03:24am | #5

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   I'm planning on remodelling an unheated kitchen (radiator removed yrs ago for more cabinet space) in a brick 2 flat in chicago (read weather extremes). I'm removing the old plaster and lathe from the brick exterior walls and want to put 3/4 styro panels for insulation between the firring strips before dry walling. Will the styro have an adverse effect on the brick as far as "breathing"/ moisture/creating efflorescene?

   Thanks in advance.