Non-typical wall construction, your opinion ?

[jimbob44]

I am planning to build (mid south location) using conventional stud wall construction.
I plan on using horizontal lapped cedar siding on the exterior and shiplapped pine planks on the interior. (Sawn on my mill from my trees)
I plan to put nothing between the cedar and pine except cellulose insulation as per the cellulose manufacturer's (Regal Industries, Inc.) instructions (no vapor barriers, etc.).
I plan on leaving the cedar bare and using clear a clear 'poly' finish on the pine.

Has anyone done something similar to this, or does anyone see any problems with it, and if so, why ?

[jraabe]

I think I'd want an air barrier in there somewhere. You will have a vapor barrier on the interior once you seal the pine with poly but that won't stop air leaks from moving air about.

A housewrap of Tyvek will keep the winds under control and reduce the potential for condensation in the cellulose. It will be best on the outside of the studs since it will help seal the rim.

Do you not have to worry about bracing? Maybe you'll do some metal straps.

If not the place will fold up pretty fast in a tornado or hurricane.

[jimbob44]

Thank  you John for you comments.
As for an air barrier, blown in cellulose is supposed to be excellent in that regard, its compaction restricts air movement, much more so than fiberglass.
And as for condensation, also excellent; cellulose wicks any moisture to it's driest part where it can evaporate, whether that be the interior or the exterior. In fact, according to the manufacturer, any vapor barrier would be detrimental to the insulating properties of the cellulose and would lead to possible moisture deterioration of the wall components. In other words, if  any condensation did occur within the wall due to very high inside or outside humidity, it would pass through via the cellulose.

[JRR]

I worry about the use of cellulose in walls of houses built in the Southeast.  If the humidity in the Southeast is high enough, and prevalent enough, so that vents are no longer recommended in crawl spaces .... can we not assume that the same high humidity will cause drying problems in wall insulation cellulose?  

Once wetted by driven rain, will the high humidity cause the cellulose to rot?

I have never used cellulose, but have been interested in it for a while.  Until I know more, if I were to use exterior wall shakes or shingles ... my plan would be the following:

1. Exterior of wall studs to be covered with landscape fabric.  This will not impede the migration of liquid or vapor ... but should stop loose cellulose from escaping, and present a plane onto which we may install wet blown cellulose.  A welded wire barrier will be needed at top and bottom to keep creatures out.
2. Next a layer of diagonal furring.
3. Next a layer of heavy building felt (we have now created a substantial drain plane!).
4. Finally horizontal furring and shingles.

Though extra materials and labor are involved, this seems like a meets-all approach and does not violate:
http://www.regalind.com/techPDF/General%20Information/Should%20You%20Use%20House%20Wrap.pdf

[MountainDon]

Do you not have to worry about bracing? Maybe you'll do some metal straps.
If not the place will fold up pretty fast in a tornado or hurricane.

From your description of your planned wall it doesn't seem like it would be very high up the list as far as resisitance to sideways forces.  Somewhere around here there is an example of the racking resistance of various wall contruction, butI can't find it!    HELP GLENN!!  

JimBob44, would you describe your climate as a "hot humid"or a "mixed humid"?  The folks at buildingscience.com do recommend blown in cellulose for mixed-humid, but not for hot-humid.  http://www.buildingscience.ca/documents/primers/plonearticlemultipage.2006-11-16.8755545932/section-1-introduction/view?searchterm=climate%20map

http://www.buildingscience.ca/documents/primers

[JRR]

MountainDon,  Thanks for that Building Science link ... lots of good info.  

But, as I read, they show a New Orleans design that uses rigid foam insulation. ... But also is shown a Lake Charles design that uses cellulose insulation.  Both locations would be hot-humid I'm sure.  I probably missed some other info that you saw.

Thanks for your time.

[glenn-k]

Sorry Don, I have been getting sidetracked by work lately - building a 2 story airplane hanger at a residence out of town. Very swamped for a bit in the near future. :'(

Here is some of the info from the old forum.  Still not totally what you are looking for though.  Maybe I'll find it.

Topic Summary
Posted by: John Raabe       Posted on: Oct 9th, 2005, 9:17am
This is another article by Paul Fisette (see beam article below).  

http://www.umass.edu/bmatwt/publications/articles/bracing_foam_sheathed_ walls.html

It explains the forces at work on the exterior of the house and why structural sheathing (OSB or plywood) gives so much strength to a building.  

When exterior foam board replaces this sheathing more sophisticated bracing is needed to hold the house together when the wind blows.

PS - Cick the "List by Titles" link on the upper left for more well done articles on topics such as OSB vs plywood, cellulose insulaton vs fiberglass, details that keep walls watertight, and others.
Posted by: Amanda_931       Posted on: Oct 9th, 2005, 6:00pm
So the standard bracing used in the 70's with black-board was fine.  Pieces of plywood the same thickness as the blackboard in the corners.  

Posted by: John Raabe       Posted on: Oct 10th, 2005, 2:21pm
Plywood at the corners gives basic structural rigidity. Alone this is not usually enough for earthquake areas and it is not as good as plywood or OSB sheathing over all the studs.
Posted by: Amanda_931       Posted on: Oct 10th, 2005, 9:17pm
Somewhere around 100 miles W of here one starts getting into a lot more earthquake possibility--the New Madrid fault.

But while there was a minor earthquake in the county some months back, Middle Tennessee doesn't worry much about them.

We could be wrong.

We do get tornadoes.
Posted by: John Raabe       Posted on: Oct 11th, 2005, 5:55pm
For 99.99% of its life a house only has to deal with downward loads. This is what we call simple static loads.

It's the sideways and upward dynamic loads that happen so very infrequently that can spell doom for a house. The extent to which you need to design and build for this varies considerably not only by the big picture earthquake, wind and water forces of your region, but by the very local sheltering or non-sheltering aspects of your site.

There are a few simple concepts that will help tie the structure together inexpensively:

• Try to get a two stud bay (2'-8" or 4' wide) panel of structural sheathing for the full height of the wall at both sides of all major corners. Nail this well to studs, plates and sills. Have horizontal panel joints meet over solid framing and nail both sides of the joint. You are building a box beam and adhesives will add even more rigidity.
• Use metal hardware such as straps, framing anchors and bolts to tie the wood framing to the foundation, the floor framing to the walls and the walls to the roof framing. You want these parts of the structure to work together and reinforce each other - especially at the corners.
• Check that all roofing, siding, sheathing and framing is installed with the right type of fasteners and at the right spacing. Many of the Katrina houses failed because framers and roofers used short staples or too few nails to keep things from blowing away. Nails are cheap insurance - use lots.

[MountainDon]

Sorry Don, I have been getting sidetracked by work lately - building a 2 story airplane hanger at a residence out of town.

Uh, how do you get the airplanes in and out of the second floor?    

I had a problem with that link not working (even with copying it all as it was broken, didn't all get included.... don't know how to describe, but you can see by looking that the blue, underlined portion doesn't encompass it all.  Maybe I'll try searching that site from the home page.

What I was remembering is a series of drawings comapring a framed wall, with horizontal 1x sheathing, diagonal 1x, sheeting of different kinds, etc.

[MountainDon]

...they show a New Orleans design that uses rigid foam insulation. ... But also is shown a Lake Charles design that uses cellulose insulation.

HMMM. I'm confused... two links I followed for New Orleans and Lake Charles both show foam on two different architectural designs. Or is there another Lake Charles design?  Here's the two I followed.  

http://www.buildingscience.ca/documents/primers/plonearticlemultipage.2006-11-17.6022614454/section-2-the-basic-hot-humid-climate-house/

http://www.buildingscience.ca/documents/primers/plonearticlemultipage.2006-11-17.4476388816/section-2-the-basic-hot-humid-climate-house/

[glenn-k]

Don said,

Uh, how do you get the airplanes in and out of the second floor?

Well - it's like this.  The owner is a bit like me - great guy.  He bought two forklift masts and they oppose each other 50 feet apart.  He is having beams designed to go between them.  The airplane will be pulled up onto the ramp on the beams.  The beams will take it to the second floor on the double hoists.  The first floor will then be open for projects as the owner desires.  I spent some time discussing different designs with him today.  Actually the airplane will be most of the second floor.  Loft in the back area.

[MountainDon]

http://www.umass.edu/bmatwt/publications/articles/bracing_foam_sheathed_walls.html

That works. I don't know what was wrong before  

EDIT: That was informative! Good article; makes one have second thoughts about not using 4x8 plywood or OSB at each corner. I never heard of diagonal studs at the corners but see how they could be advantageous. Not too sure I'd trust some of the local hired help   to put it together, but that's another story.

Also interesting was the quote about Simpson... Simpson Strong-Tie's product manual clearly states that metal wall braces prevent walls from racking during construction and are not designed to replace shearwall load-carrying components.

[JRR]

Mountain Don, confusing it is!  Open the pdf file and check out page 5:
http://www.buildingscience.ca/documents/primers/lake-charles-la-house-drawings/

[MountainDon]

(re 2nd floor airplane)
Well dang, that's too clever, Glenn!!

[MountainDon]

Mountain Don, confusing it is!  

Hmmm??   :-?  More than one way to skin a cat, I guess.    I see that plan uses a layer of exterior foam as well, similar to the cold zone design with cellulose wall insulation and 1" of foam.

Good Article on Cellulose...
http://www.umass.edu/bmatwt/publications/articles/cellulose_insulation.html
One of the keys to a satisfactory job if using the wet application method is choosing the right contractor.

[jimbob44]

Somehow, this thread got sidetracked on the rigidity of the wall instead of the insulation. Of course, I would brace the wall with diagonally inlaid 1x4.
The thought on the insulation was that cellulose makes a good insulation choice especially for preventing air infiltration and moisture problems, and that it's correct installation uses no vapor barriers of any kind.
Regal Industries, a cellulose manufacturer, has some interesting reading on this topic at http://www.regalind.com.

[jraabe]

Here is the diagram of comparative rigidity of wall structures.



My own experience with cellulose insulation is that it has not performed up to expectations. I used it in a house many years ago where the installer used treated cardboard baffles and them pumped the cellulose behind this to a specific density. I did a floor and ceiling of a concrete block house. We did not insulated the walls.

There was very little change in comfort or heating bills. Of course, the windows and walls were still poorly insulated. However, that supplier is no longer in business. Not sure why.

The only insulation that I am confident combines good airflow control with a high R-value/inch is Icynene spray foam. It is so expensive that I only use it for airsealing tricky places such as floor rims and rafter floor connections.

That said we don't have much experience with wet spray cellulose in the NW - I think the climate is too wet already and builders don't want to add a moisture laden product to the walls. However, if you have an experienced installer and (hopefully) have someone who has used it the way you plan to, then good-on-ya and all the best.

[MountainDon]

Here is the diagram of comparative rigidity of wall structures.

That's what I was thinking of . Thanks.