Insulating the Roof with Polyiso foam boards

I finally climbed up on the roof during the process of installing the 2 layers of polyiso foam boards. I think you can see what the guys are doing here.

First they install a solid layer of 1.5" polyiso across the roof and tape the seams. I don't have a photo of this step.

Then they install nailers which the second layer of 1.5" polyiso in place and tape those seams as well. The function of the nailers is to give the roofers something to easily attach the roofing to.

This method also allows us to add an overhang with no thermal bridging, no direct connection from the inside of the house to the outside of the house. This way the rafters cannot conduct heat to the inside or outside whichever is colder. 

It is a fairly complicated working on the roof the this way, but it seriously enhances the thermal boundary of the house. We do have porches on 3 sides of the house which makes this work so much easier. 

In the photo below you can see the underside of the rafters and how the overhang is built.

Sealing the edge of the foam on roof

To add more effective insulation on the roof and to eliminate thermal bridging we have add 2 layers of 1.5 inches of polyisocyanurate foam insulation. The first layer was applied as a continuous layer on top the plywood and the felt. Then the second layer was installed between 2 x 4 nailers with no overlap of seams below. I'll get Carlton to take some pictures tomorrow. 

This photo is from a commercial construction site but it demonstrates that the seams between the polyiso are staggered so you don't have a continuous seam where they line up and leak air, heat, and moisture. (http://continuingeducation.construction.com/article_print.php?L=140&C=442 accessed on 8-25-13) 

I am trying to figure out how to seal these edges of foam on the roof. I meant for the Carlton, Chris, and Myron crew to do that as they went along, but I did not specifically tell them to do that. 

I have posted a question on Green Building Advisor for help with this matter.

Who needs a blower door test?

Who needs a blower door test when you are in the middle of a Southeastern US monsoon season? I am pretty sure we are getting an inch a day of rain in the month of August. The ground makes a squishing sucking sound with you walk on it. It's pretty amazing.

It is also challenging trying to build an air tight house under these circumstances. I certainly don't need to do a blower door test to find the air leaks when I have puddles of water everywhere.

Corner detail. The guys are going to patch that when they install the 2 layers of polyiso on the roof.

Second floor dormer - major leak in on the right of photo.

These seems to be where the leak is coming from, but I thought I had closed it up by using Prosoco Joint and Seam sealer. Apparently not.

Another view of the leaky area. I think I didn't tool the seam sealer very well and it didn't really block the water. The house wrap has not been installed yet, but I want these problems fixed BEFORE the housewrap goes on. 

Leak on second floor gable end

I thought the leak was from the junction between the porch and the gable wall, but my flashing did not completely solve the problem. I have reinforced the roll flashing and the tape on the sheathing. 

Tonight's photo. First floor leaky area below the same gable end as above. It is driving me crazy.

Orb Weaver Paradise

For the past 3 years,  I have watched an orb weaver spider spin a web on my fence and lay numerous egg sacs. She would trap lots of bugs, then get really huge, then lay an egg sac and get skinny. I saw this happen over and over. But each year I only saw one on my patio. This year, there are at least 8 different ones on a small section of fencing. There is apparently no shortage of food as most of them are getting fat. 

These are iPhone photos, but they give you an idea of the number of spiders. 

This is the mother of them all. She is huge. I think she has the prime location.

Underside of another

Small orb weaver under the big Mama spider (and yes, I need to paint the fence. Please ignore.)

Daisy the cat walking on the patio near the 6-legged spider

Underside of 2 spiders here.

Air sealing

The guys have been working really hard putting the sheathing and air sealing. The house looks beautiful.

I have been caulking the inside while the outside is being taped. This is redundant, I know, but as this is the first house I have ever built and I am trying to build it to a high standard, I don't mind the redundancy.

The tape is Tescon Vana from 475 High Performance Building Supply in Brooklyn, NY. It is very sticky stuff.

The interior caulk is Prosoco Joint and Seam Sealer which I got from another high performance building supply company called Small Planet Workshop. I've got to order some more stuff from both of them.

There are no windows framed on the back dormer because we're haven't decided what kind of window will go in the bathtub/shower area. We will almost certainly choose a vinyl window. That's why the photo of the back dormer looks so odd. They haven't taped it because they will be cutting the sheathing where the window goes.

View of the enclosed front porch

Driveway side view

Back of house

Topped Out

Carlton told me about the tradition of putting a tree on the building when you get the framing topped out and in the dry. Now that the roof sheathing is on everywhere he put up the pine branch on the second story framing.

Front views of the house

Back view of the house

Next week - framing the rough openings for the doors and windows, then more sheathing, then electrical and plumbing starts.