Roof: vertical and horizontal strapping

Since my last post, I've continued to work on the house as the weather has permitted. On Sunday, my dad and I sheeted the back of the roof and put the felt paper on it. I also added some braces under the eaves on the ends of the house. There was two feet of 7/16" OSB with a 2x3 hanging out past the end of the frame there. Adding some 2x braces from the edge of the overhang to the house frame helps to stiffen up that part of the roof. Eventually, there will be some framing to help support the overhang of the OSB. This framing will be on the outside of the bale walls and will support the wood siding. I'll add this when I frame the porch -- framing the porch comes after the roof is finished.

Monday was a nice day with a temperature of more than 70 degrees. It was quite breezy, though. With the sheeting completed, I was able to begin installing the vertical and horizontal strapping. The vertical strapping employs 1x2s which I ripped from 1x6s. The 1x4 which I also yielded by ripping these boards serves as the horizontal strapping. The vertical strapping is on 2 foot centers, directly over the rafters I added for the insulation space.

I attached the vertical strapping on the back of the house before moving on to the front of the roof. Actually, I was going to install the horizontal strapping on the back before beginning on the front, but the combination of warm temperatures, warm sunshine, and windy conditions led to portions of the felt paper on the front of the roof tearing loose from the staples that were meant to hold it on the OSB. Rather than leave it flapping in the breeze, I stapled it some more, finished the vertical strapping on the back, and then began installing vertical strapping on the front. I figured that with 1x2s nailed onto the front every two feet the felt paper wouldn't tear loose very easily. (I know that stapling tar paper on a roof isn't the ideal method of applying it, but it was the quickest way at the time.)

After installing the first 8' 4" of strapping on the front, my dad joined me and assisted in putting the first five rows of horizontal strapping on the front. He handed the 1x4s to me, and I nailed them on.

It rained Tuesday, but today was a nice day in the mid 40s. So, with dad's help, I added more strapping. We finished the front of the roof by lunch time. After lunch we completed the installation of the horizontal strapping on the back of the roof. Since it is a less steep pitch (3:12), it went quite quickly.

We measured to make sure that everything was as it is supposed to be so that that metal roofing will end up square and that it is the right length. Things checked out like they were supposed to, so we'll start installing the metal on the front in the morning (the forecast isn't calling for rain).

The reason for the strapping is to provide a ventilation space under the metal roofing. The vertical strapping allows any condensation on the underside of the metal to drain out to the bottom by holding the horizontal strapping up off of the sheeting. The metal will be screwed onto the horizontal strapping. With the sheeting and the strapping, I shouldn't have any problems with condensation. I also expect that it will help keep the heat of the summer sun from warming the inside of the house (along with the ten inches of dense pack cellulose between the roof sheeting and the cathedral ceiling, of course).

The sheeting and the strapping aren't perfectly flat like I would prefer. There are some high and low spots (you can see some in the photos). I've tried to avoid these, but I haven't been perfectly successful. The 1xs I used for the cathedral ceiling contributed to some of the unevenness because of how they have moved because of moisture. Tar paper keeps most of the rain off but not all. Some water gets under the paper. Sometimes, it seems that it is better at keeping moisture under it from getting out than it is at keeping it from getting under it. This created some issues for the ceiling boards and will require me to sand out some water marks later.

Also contributing to some of the unevenness of the roof is the bow to some of the 2xs I used for rafters. I put the crown up and held them as consistently at ten inches from the ceiling boards as I could, but they were not even at all points along their lengths. Once the metal is installed, I'm hoping that most of the unevenness will not be noticeable. My consolation, though, is that it will be a solid, well-insulated roof that has cost me less than half what it would have if I purchased more "perfect" materials. I could only guess at how much it's saved me from paying someone else to install this roof. In my case, I have more time than money, and I won't be able to see the roof when I'm inside the house anyway!

I say all this, but it really isn't that bad. It's just a small irritant to me that it isn't perfectly even, however unrealistic that is.

I'm looking forward to finally having the roof finished -- only six months later than I anticipated!