You can "stand by" R8 all you like, but even with infiltration and thin spots in the EPS it's performing considerably than that, even a 30mph breeze. If you can make a case that they're skipping whole stud-bays maybe you can get net performance that low, but seriously, even with R11s with numerous smaller compressions & gaps, and ONLY half-inch EPS with a bunch of major slashes in the housewrap it's still going to be in the R10 range, which sucks, but it's better than R8. I'd need real data (not just a WAG) to believe that it's performance is really that low. Even half-inch foam buys a lot.

Also fiber insulation has a "heat exchanger effect" on infiltration & exfiltration paths- the infiltration losses (while still substantial) aren't nearly what a simple math model of 0.18 BTU per degree-F per cubic foot of infiltration model suggests, at least when flowing through the fiber as opposed to a 1" gap the top or bottom of a stud bay. (Building Science Corp is currently cooking up a better model using test assemblies.)

I'll bet most of that stucco has major cracks and fissures going on within 5 years if they're framing it without racking reinforcement. Does AZ have building code enforcement anymore? As I understand it the AZ statewide code is still based on IBC 2006, but most cities & towns have amended or newer versions in place, though some have none. Since it's only administered by municipalities, if there isn't a budget for an inspector, some towns are just skating, hoping the builders are doing the right thing.

Posted By Dana1 on 24 May 2013 11:49 AM
You can "stand by" R8 all you like, but even with infiltration and thin spots in the EPS it's performing considerably than that, even a 30mph breeze. If you can make a case that they're skipping whole stud-bays maybe you can get net performance that low, but seriously, even with R11s with numerous smaller compressions & gaps, and ONLY half-inch EPS with a bunch of major slashes in the housewrap it's still going to be in the R10 range, which sucks, but it's better than R8. I'd need real data (not just a WAG) to believe that it's performance is really that low. Even half-inch foam buys a lot.

Also fiber insulation has a "heat exchanger effect" on infiltration & exfiltration paths- the infiltration losses (while still substantial) aren't nearly what a simple math model of 0.18 BTU per degree-F per cubic foot of infiltration model suggests, at least when flowing through the fiber as opposed to a 1" gap the top or bottom of a stud bay. (Building Science Corp is currently cooking up a better model using test assemblies.)

I'll bet most of that stucco has major cracks and fissures going on within 5 years if they're framing it without racking reinforcement. Does AZ have building code enforcement anymore? As I understand it the AZ statewide code is still based on IBC 2006, but most cities & towns have amended or newer versions in place, though some have none. Since it's only administered by municipalities, if there isn't a budget for an inspector, some towns are just skating, hoping the builders are doing the right thing.

My-my, aren't we a little testy here.

When I had an inspection/energy audit done on my home the thermal images found wall areas that were completely missing insulation. The supposed R-38 attic insulation was more like R-30 as numerous areas were missing insulation or they had settled and only 6" remained. I had them blow in a few more inches of the loose fiberglass and got it to around 13"- 15". I believe I am around R-40 right now. Over 20+ issues were discovered on the 1-year old home, all of which were submitted to the builder and they at first refused to fix them but some threatening letters and a call to the County changed their mind.

They will occasionally put OSB on the corners of a 2-story to help with racking and there will be the occassional strap installed (if it is nailed down correctly). As far as code enforcement goes. The inspector would sometimes drive by the home and never get out of the car and simply check-off the home that it was inspected. This was very common during the building craze of 2004-2008. Even if they did get out and inspect, the code is a joke out here. The allow them to use dimensional lumber that is completely full of bark as a structural piece. Instead of throwing it in the scrap, they will run 30 nails into it so they can use it.

Racking is more prevalent on the 2 story homes. My gable attic vent is a prime example. The gable wall could be moved with one hand as there is no OSB up there. It would literally move a over an inch if you put a hand on the wall. During wind storms you could go into the attic and watch the gable ends move in and out like an accordion. Eventually the large gable vent shifted out of place and when it rained the water would come in and cause interior wall damage. I had to brace the gable ends and they had to come out and reinstall the gable vents.

Sadly, my home is actually the better built homes out here. There are plenty of junkier built homes, that is for sure. I've seen them lap the tar paper the wrong way, so when it rains the water is funneled behind the tar paper and into the wall cavity. To get a window installed they would run a nail through the BOTTOM of the window frame, right into the drain weep channels. So when it rains instead of the water draining out, it goes into the nail hole and drains into the wall. Welcome to Phoenix, Arizona home construction. I hear Nevada is just as bad.

Southern Utah as well. My mother-in-law had a house down there, she wanted me to add an outlet on her patio. I cut the hole, 1/2 inch of stucco, then 1/2 inch of foam, then I was in the bay. It was kind of a what the heck moment. The stucco had been applied very dry (easy to have happen in that climate), and it fell to powder as I cut into it. I had to epoxy the sides of the cutout to get it to support the box. I think the only thing holding it together was the paint, so I wouldn't count on it to supply any racking strength. I did see other houses under construction in the development, and they were strapping the corners, but that was about it.

Posted By dave111 on 24 May 2013 11:50 PM
Southern Utah as well. My mother-in-law had a house down there, she wanted me to add an outlet on her patio. I cut the hole, 1/2 inch of stucco, then 1/2 inch of foam, then I was in the bay. It was kind of a what the heck moment. The stucco had been applied very dry (easy to have happen in that climate), and it fell to powder as I cut into it. I had to epoxy the sides of the cutout to get it to support the box. I think the only thing holding it together was the paint, so I wouldn't count on it to supply any racking strength. I did see other houses under construction in the development, and they were strapping the corners, but that was about it.

That's correct, I remember hearing that southern Utah was also cheap construction.

That's typical of the stucco here also. It has absolutely NO strength to it. I ran a masonry screw into it trying to attach a hook and the stucco crumbled into dust as soon as the screw touched it. The only way to attach the outlet box is to attach it next to a stud in the wall. You can litterally take a long flathead screwdriver and with one hand gently push and it will penetrate the outside wall and the screwdriver will end up past the drywall and you will be inside of the home.

Tyvek's Drainwrap is a wrinkled house wrap. When you fasten panels or planks over it, flattens cutting off drainage and air circulation. Your best bet is to use Ben Obdyke's Hydro Gap or Tamlyn Wrap, which have extruded filaments spacers. In case you have to install furring strips, these filaments will create a standoff between the membrane and furring strip allowing it to drain behind the board, avoiding water accumulation and damage to the membrane...

For a stucco application, I would you a secondary house wrap or at least paper over any drainable house wrap to create that drainage gap.

From somewhere I recall that a double layer of Drainwrap or Drainwrap + normal WRB was much better than a single layer of Drainwrap.

I was talking to a Ben O rep and he had his little clear plexiglass contraption to put a piece of
housewrap tight between two pieces of plexiglass and dump water on top and watch how fast it drained. Of course their hydro gap outperformed tyvek drain wrap, but I had him do regular tyvek and then tyvek drainwrap and I was shocked how well the drainwrap worked, so it works.

That said, their Hydro Gap was way better than Tyvek Drainwrap in their little demonstration as far as draining water.