Exterior Walls: 2x4 vs 2x6 ????

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  #1  
Old 10-23-01, 02:57 PM
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Question

Planning to build 2nd house. First house was in MN and was it standard to build exterior walls using 2x6's.

Moved to lower Michigan and have decide to build a basic 2 story "saltbox". The contractor I am considering tells me that it is standard here to build exterior walls with 2x4's. He will build with 2x6's if I so desire but at an xtra cost.

What are the advantages of a 2x6 wall over one built with 2x4's? Is it a structual/strength issue? An insulation issue? (The walls would be insulated to same necessary R value, correct? Same zone as my previous house)

What would be the main advantage of a 2x6 wall over 2x4?

Please clear this up for me?

Thx

Nodak
 
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  #2  
Old 10-24-01, 11:10 PM
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The main advantage of 2x6 as oppossed to 2x4 is insulation value, R20 over R13. However, you can still achieve R20 with 2x4 walls by applying a 2" layer of extruded polystyrene on the stud exterior. This is a better insulated wall as it prevents heat loss via conduction through the studs (Thermal Bridging).You need to be familiar with the local building requirements for insulation values.If authorities have set R13 as a minimum then some contractors will meet this limit. But it is a MINIMUM. Framing walls with 2x4's require 16"O.C. Using 2x6 exterior walls you can use 24" centers, using less lumber, and you can still apply the rigid insulation on the exterior for a R28 wall.
Here is something to consider. Seventy per-cent of heat loss is stopped in the first 3" of insulation. After that the return on investment of added insulatiion diminishes. Equally important as the insulation is the air tightness of the envelope. You can insulate as much as you please, but air leaks can carry away a lot of your energy dollars.
Best of luck.
 
  #3  
Old 11-03-01, 02:10 AM
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good info allen,,,
another option would be the spray applied polyurethane foam insulation. this would provide a seamless air infiltration barrier in addition to high r-values. an R-19 is easily obtained in about 3" of product, and it can out perform fiberglass systems by about 50% once wind is "working" on the structure. additionally, it provides an effective sound deadening barrier greatly reducing noise pollution.
let me know if i can provide you with further information
mark
 
  #4  
Old 11-03-01, 03:36 PM
rbisys
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Greetins Nodak,

You will never save in energy what it costs to go from 2x4 to 2x6.

I would suggest a radiant barrier system for the walls a ceiling. My experience is that a fiber glass house will use at least 40% more winter energy and up to 200% or more a/c energy than a radaint barrier house. You can also wrap the exterior with a perforated radaint barrier which will help insulate the wall studs and act as an air infiltration barrier.

The foam is extremely costly and will probably not perform as good as the radiant barrier system as it will lose the gases that help give it its "R" value. I live in a foam panelized house and find the sound reduction disappointing.

The radaint barrier is not carcenogenic and will not cause condensation or mold/mildew to form.

If you cannot find a contractor up there that does radiant barriers and you have time to DIY let me know and I will help you with the info you need.

For more radiant barrier info enter into your search engine, "radaint barriers" or "reflective insulation".

Minimum requirements for your area is two layers ceiling and walls, three layers maximum.

Thank you for considering my opinion.
 
  #5  
Old 11-04-01, 08:51 AM
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If your building a new construction home here is my suggestion on properly insulating your home.

First most heat loss is due to air infiltration through electical outlets, small spaces around window and door openings etc..2nd largest heat loss is through ceiling areas.

Prior to installing any insualtion I would foam seal around all windows, doors and electrical outlets and any other penetrations through exterior walls and ceilings.. Use caution to apply foam products appropriately.. approx 1/2 thickness is all that is necessary for the faom to stop the air infiltration.. the balance of any gaps can be filled with fiberglass scraps left over from the installation at walls and ceilings.

The I would install R-13 Kraft Faced fiberglass batts in all exterior walls. In the ceiling areas that are accessable from the attic I would install R-19 fiberglass batts and then blow an addition R-19 of loose fill fiberglass or cellulose over the top... This will fill all voids and the nooks and cranny's you can't fill completely with a fiberglass batt..

In conventional framed areas where access to the ceiling area is not accessable put in the maximum amount of insulation available..

2" x 12" s high density r-38 batts
2" x 10" s high density r-30 batts
2" x 8" s high density R-21 batts

here are a few websites I reccommend you visit prior to starting your insulating..

http://hem.dis.anl.gov/eehem/96/9609insulation.html

http://www.ornl.gov/roofs+walls/insulation/ins_08.html

http://www.ornl.gov/roofs+walls/radiant/rb_05.html

If you would like further advice just ask

Good Luck

Jim


 
  #6  
Old 11-08-01, 06:09 PM
rbisys
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Greetings,

Kraft paper fiberglass (FG) has an extremely high fire spread rating not to mention that the fumes from the pitch that is used as a glue will be comming through your walls.

The "R" values qouted are for lab conditions, bone dry, very low humidity and minimum radiant energy effects. Tests by a major FG manufacturer in the late 60's showed about a 50% drop in "R" values in installed winter conditions.

There are no advantages in going from "R" 19 to "R" 30-38. You will probably never pay for the costs of the additional material. FG also loses a grat deal of its "R" value in the ceiling too.

By the way the websites mentioned are the ones that are designed to disciourage you from using radiant barriers. I covered these on another thread.

Remember these fiberglass salesmen are trying to get you to use a material that not only cannot perform in your walls and ceilings as advertised, it can also damage your home and affect the health of you and your family. You can find plenty of FG health related problems on the web.

Thank you for considering my opinion.
 
  #7  
Old 11-11-01, 07:22 AM
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First I like to say the replies were very informative but I would like to read what you guys will do with this. There is a third option you can consider when building a new home. That is STAGGERED WALL CONSTRUCTION. The unique aspect of this type of construction is the vast majority of studs do not go directly from the inside wall to the outside wall and is considerably sounder than the other two types of walls. The way this wall is constructed is two 2x3 plates are put side by side around the perimeter of the home. In the cornor on the outer 2x3 plate a 2x3 stud is put and subsequent studs put 16 inches on center. On the inner plate, 8 inches on center from the cornor a stud is put and subsequent studs 16inches on center. This puts all the 2x3 studs on the inner plate halfway in between the studs on the outer plate. Therefore the inner plate studs do not touch the outer wall and the outer studs do not touch the inner wall with a stud every 8 inches on center. How will you guys insulate this one? And by the way, the wall is 6 inches thick.
 
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