I’m having a new home built this summer. I live in southern Wisconsin. I’d like some tips on the best construction method for the exterior walls on my new home. So far, I’ve had three options bid out, all with 2×6 with studs 16″ oc and Tyvek house wrap:
- 1″ foam sheathing with metal corner bracing (12′ reinforced metal bracing run diagonally at corners)
- 1″ foam sheathing with 1/2″ plywood or OSB corner bracing (with 1/2″ foam sheathing).
- 3/4″ plywood/OSB exterior walls covered with 1″ foam sheathing.
Which is best? I like the third option for the strength of the construction. I’ve never liked the thought that someone could kick through the exterior walls if you just use foam sheathing. Any other comments or thoughts would be appreciated. Thanks!
Edited 5/16/2002 5:03:08 AM ET by YODADA
Replies
YODADA,
We use 2x6 ,16 on center, for walls all the time,1/2" ply wood is more then enough as sheeting.Most windows and doors are made with standard size jambs 6+9/16" or 4+9/16" that fit walls 2x6 with 1/2" ply outside and 1/2" rock inside or 2x4 walls with ply and rock.
3/4" just seems like a waste for wall sheeting to me.
Vince Carbone
I agree...1/2" sheathing is plenty...and why the foam? (I'm just an ignorant Oregonian but always curious...it doesn't get very cold here on the coast). Some people would bitch even if they were hung with a new rope.
I agree with the others, that 3/4" plywood is a total waste on the outside of a house. No way does a house need that much shear strength.
I'm not a fan of metal braces - You need lots of nails and lots of braces to even come close to the strength gained by using plywood corners.
Two thoughts come to mind. The plywood corners with 1/2" foam (and 1" foam on the remainder) sounds like a good option. I know people could theoretically "kick through the exterior walls" if they wanted to. But have you ever heard of it happening?
If you don't like the foam, use plywood or OSB on the exterior, and upgrade the insulation in the walls to something better. I think wet blown in fiberglass will give you an R value around 23, compared to R19 for typical batts. Or maybe try icynene.
Avoid cliches like the plague.
1/2" ply or OSB on outside and 1" foam on inside.
Foam on out can cause rot from trapping moisture.
3/4" ply is wasteful, not to mention my aching back from thinking about the installation. Save the bucks for the foam.
You don't mentiuon subfloor so I wonder if you misunderstood the bid? Is He figuring 3/4" Ply subfloor which is where it belongs - that is unless he has learned that Advantex subfloor is the way to go.
Piffin,
I'll bite....what is Advantix subflooring?
Davo.
jesus! try putting it on the roof. (oww, my back)
Jesus could do it! He works the high stuff from the top.
Excellence is its own reward!
Advantex is the subflooring t&g material that looks like OSB but is much better and thicker. It'll stand up to ;oads of snow and rain in the extended construction environment.
The crumbling foam may have come from being left exposed to the elements for too long. Most manufaacturers recomend no longer than thirty days of UV exposure. If that orginal builder was so careless in other areas, he may have taken forever to get it covered up or to install the door, leaving the edges exposed. Or he might have bought it from one of those seconds / liquidators places where it had been outside on a palatte for a year first.
Excellence is its own reward!
Jesus retired from construction. He does this teaching thing now.
That's right; his last experience with a hammer and nails was a real killer. Then he saw the light, got out of construction and had an uplifting experience.
May we all take one of his lessons...
Holiness is its own reward!
Done the 3/4 thing on the roof 3 or 4 times too. Damn them architects, I think they get a kickback from plywood manufacturers. I used to be 6' tall, now only 5'7", after those homes. Lots of sheets.
Brudoggie
can't even climb into the back of the truck anymore. Had to get extendo-bed.
have to start taking flexeril two days before hard-hitting work.
Edited 5/17/2002 8:13:19 PM ET by panama red
Hired a 19 yr. old to do the hard work. I just stand and bark orders. (Yeah right) He and I just finished sheathing 12/12 roof on 30 x 50 garage. Only 5/8" this time, piece of cake. Except the 6 dormers, "what a garage" .
Brudoggie
1/2 " plywood is enough, done some 3/4 as architect spec, hard on the crew( maybe slower at the end of the week). If you really think you need the foam, Piffin is right, put it inside. I'd just save the $ and put it towards High density batts( R-21), stabilized polyfilm, airtight electrical box enclosures, and good sealant for poly joints. We put the " first string" on insulating & especially vapor barrier installation. If your house is going to be that tight, you've got a ventillator right?
Good luck,
Brudoggie
Okay, I goofed...that's what I get for typing when I'm half asleep. The actual bid provides an option for "install 7/16 inch exterior wall sheathing in addition to 1 inch styro". The contractor described the 7/16 sheathing as OSB.
I guess part of my reluctance to just use just Styrofoam is that my existing home is 11 years old and was constructed using 1" styro, no wrap. I replaced a garage window and exterior door last summer (the originals were cheap - door was an interior hollow core door - great construction - I put in a good steel exterior door) and the styro around the frames was crumbling. I had to strip the siding and replace the styro. Was this just cheap material? Was it a lack of wrapping? I don't want to build a new home knowing that the exterior walls are going to disintegrate after 10 or so years. Any thoughts on this?
We have an air exchanger in the HVAC. Should we use BIB insulation or batts? The builders are pushing the BIB system, but I haven't found much info that is definitive that BIB is better. Thanks again for the feedback!!!!!
Davo - the exterior will be mostly vinyl w/ about 50% brick on the front. Thanks!
Edited 5/16/2002 10:03:38 PM ET by YODADA
Yodada,
Could have been cheap foam, was it the bead type? There are lots of causes for degredation. As for blown in, versus traditional batt, each has its supposed advantages. Blown , better coverage around electrical boxes,etc. Batts probably just cost ,and the fact the system has been proven for decades. Personally, I like batts, applied very carefully, with a well sealed vapor barrier. If you decide to go with blown, make sure applicator has sufficient experience. Lack of proper technique can quickly elliminate any benefits of the system. This also applies to batts, but most builders have plenty of experience with batts.Hope your new home proves to be more pleasing than the last. As for sheathing, 7/16 is ok at 16OC, but I use 1/2 , prefer plywood to OSB, just my oldschool teachings.
Brudoggie
Edited 5/16/2002 11:23:12 PM ET by BRUDOGGIE
Thanks Brudoggie!
Ya, my current home is not the best. I also had problems with the basement. Leaked at the tie rods (from the forms). The builder didn't break off all the ties and seal the exterior of the foundation. What a pain fixing that problem this year (and not cheap)! That's another thing that I'll make sure is taken care of this time around.
So your recommendation for the best exterior wall is 1/2" plywood, no styrofoam, high density batts, etc. Thanks for the info!
Yodada
Since you mentioned foundations and leaking form ties -
I used this stuff last year:
http://www.deltams.com/deltams/index.html
I'll never build another house without it.
Exaggeration is a million times worse than understatement
Hi YODADA,
Plywood corners are always better for shear strength and racking. A lot of homes that are going to have a brick veneer exterior in my area are sheathed only with the foam; however the corners are still plywood, not metal braces.
I personally think the foam is a waste. I would much rather have my home sheathed with wood. A lot of homes around here are sheathed using either 7/16 OSB or 1/2 inch (4 ply) plywood. I agree with everyone else that 3/4 is overkill for wall sheathing.
What is the planned exterior for your home?
Davo
YODADA,
Here's my version of a wall, exterior to interior:
Half-inch ply over 2 x 6's. Stud cavity insulation is blown in cellulose. Gets in to all the nooks and crannies and has a few upsides compared to FG.
On the interior, I use 1" foil-faced polyiso insulation (R7.2 per inch) over the studs. Sheets gapped by about 3/8th of an inch, then the gaps are foamed with canned foam. Over the polyiso goes furring strips, horizontal at 16" oc. Drywall gets screwed to the furring strips. Good detailing on any electrical boxes will give you near air-tight construction.
Your house will be tight, it'll be phenomenally quiet in terms of outside noise (lawnmower, screaming neighborhood kids, etc) penetration, you'll need way fewer BTUs in the winter and you can likely omit air conditioning in the summer due to the foil faced polyiso.
Used to live in Cheddarland...still have a place up on Big Cedar (Big Cheddar) Lake up in Slinger. In-laws are in Elm Grove, just outside of MKE. I'll be up at Big Cheddar in June/July.
Cheezily,
Mongo