Replies

1. 
   rez | Sep 23, 2006 02:47am | #1

   What are your insul values now as it is?

    

   The bitterness of poor quality remains long after the sweetness of low price is forgotten.

   
   

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   Edited 9/22/2006 7:48 pm ET by rez

1. 
   tfarwell | Sep 23, 2006 06:16am | #4

   I have 2x4 walls, built in 1977. The insulation is sprayed in foam - I couldn't believe it until I open up sheetrock and looked. So I am assuming about R13.

    

1. 
   rez | Sep 23, 2006 06:28am | #6

   Don't know if you're in a very cold environment or not but seems that foam insulation more than suffices for a wall as it gives true values.

   Being just a wall and already tight it seems hardly worth the effort for what little bit of value you would be adding but it's your call and your place so if you want to then go for it, if not just for the feeling of accomplishment.

   Now if a whole wall were already opened it might be a matter of principle to go ahead and place another layer there. IMHO

    

   The bitterness of poor quality remains long after the sweetness of low price is forgotten.

   Edited 9/22/2006 11:32 pm ET by rez

1. 
   tfarwell | Sep 23, 2006 06:33am | #7

   Thanks rez - you make good sense. I live outside Portland, Oregon. The climate is not too cold, but kinda wet a lot of the year.

1. 
   PatchogPhil | Sep 23, 2006 08:19am | #8

   Sounds like you are NOT considering putting the 1" foam board on the wall ABOVE the counter tops (because your counters are extra deep).  That wall area is the only spot open to the air of the room. 

   From an insulation point of view that area above the counters would benefit more from extra insulation (cabinets do add ~some~ insulation and block air flow across the wall surface),  but.....  since you need the depth for the extra deep counters....  See what I mean? 

   There will not be any noticeable difference if you add any insulation behind the cabinets.

2. 
   tfarwell | Sep 23, 2006 06:28pm | #10

   I am going with the theory that a room is a system that has a given overall R value on the exterior walls, and that increasing some locations gives an average improvement.  But behind cabinets is an interesting question - since I already have some default insulation and airflow blockage as stated above. I have foam in the walls, but the 1 inch rigid foam will stop some level of thermal bridging.

   Either way, I will fir out the cabinets with 1 inch strips. I an just interested in the topic of adding R to the envelope where you can. I have checked out the building science website, but there is not a lot on this specific topic.

   I figure 2 sheets of 4x8 rigid foam is going to be $30. Labor to install between the firring strips that backup the cabinets, not much.

   I also have soffits in the kitchen, which I am keeping. I am planning on insulating those with fiberglass. I will drill some 4 inch holes into the stud bays to allow for airflow.

    

    

    

    

    

    

    

    

2. 
   PatchogPhil | Sep 23, 2006 02:47am | #2

   Well,  it might keep the backs of the cabinets extra warm.  But I doubt it will affect the rest of the kitchen. 

    

3. 
   WayneL5 | Sep 23, 2006 03:03am | #3

   I don't know for sure, but there is a potential problem that can arise.  If you insulate how you propose, then the wall surface (that is, between the insulation and the wall) will be colder than it is now.  That might invite condensation, especially in a kitchen which has high humidity.  It won't dry well behind the foam so you may create conditions for mold on the wall.

1. 
   tfarwell | Sep 23, 2006 06:27am | #5

   Yup - that was my concern: mold, mositure.

   I figure adding 1" of foam is almost free in this case, and has to help out in some way, especially in the summer. Most of the kitchen is facing south and gets full sun from about 4 feet down (eves block the rest)

   I want to get every "R" I can, but not at the expense of moisture problems. If moisture is a problem like this, why don't cabinets with melamine backs trap it as well?

    

1. 
   WayneL5 | Sep 23, 2006 05:28pm | #9

   Insulation over the wall will make the wall surface colder than if just cabinets were against the wall.  So it would be more prone to condensation.  I can't say for certain that 1" of insulation is enough to cause condensation, only that it tends in that direction.