Roof design

I've been thinking about the roof. It will be a metal roof for which I've already purchased the metal in ten foot lengths. I got it for about half price because it's 'rainbow' colored. That means it's mostly green because it was painted as they switched from one color to the next. That's not a problem because it will eventually be sprayed with a ceramic coating by a friend of mine.

What I've been thinking about is how to construct the rafter system for the metal roof which allows me to blow cellulose insulation to an R-value of 50 or more (I don't want super-insulated straw bale walls without a super insulated roof as well). A 14 inch space for the insulation should allow for the R-value I want. This week I designed on paper the rafter structure that will allow me to accomplish this. My design looks like the picture to the right.

I calculated how many 2x4s it would take to construct these and shocked myself with what it would cost. My budget for this year is rapidly dwindling, and my class load this semester (only one section) doesn't allow any extra money beyond what's needed for monthly expenses. So, I did an assessment of what I have that is usable. I have nearly 200 2x3s that I milled several months ago. I was going to use them for other parts of the house, but they will work for this roofing need. So, that saved several hundred dollars.

The other part of the roof design that I've been pondering on has to do with condensation and venting the roof. A metal roof can more readily have condensation problems than many other roofing systems. My original idea for the roof was to build the rafter system on four foot centers and use 2xs for purlins on two foot centers to which the metal would be attached. This plan didn't allow for dealing with potential condensation problems.

I could use OSB or plywood sheeting on top of the rafters. Then, the metal could be attached to that on top of a moisture barrier. That would still not deal with space between the roof and the insulation for venting (a 1 inch space is the minimum). Also, 50 sheets of plywood or OSB isn't cheap (and my budget is thin). Sheeting would also necessitate a change in rafter spacing, but that's not a problem.

So, at this point in time, here's my plan: I will build the rafter structure as designed on 3 foot centers. Then, I will sheet the roof with 'slab wood' from a local pallet company. This 'slab wood' is actually boards resawn for pallets that come in 4" or 6" widths, 3/8" to 1/2" thickness, and usually 42" lengths. They sell a pallet of these for $2.00. I will buy several pallets of them, cut them to 36 in lengths, and then staple them to the rafters. On top of this sheeting, I will put down 30# roofing felt.

I will also buy about 150 1x4s from Cub Run Hardwoods. I'll cut most of these to 6 foot lengths which will span across three rafters. The 2 foot lengths I cut off, I will rip into 1x2s. I will attach these 1x2s onto the sheeted roof above the rafters as vertical stringers. The 1x4s will be placed horizontally across the vertical stringers to serve as purlins for the metal to be attached to. The vertical strapping will provide the ventilation space and the ability for condensation to drain to the bottom of the roof and out the venting.

That's my plan right now. It is contingent on a few things, like acquiring the pallet wood and the 1x4s, but that shouldn't pose a problem. It should create a roof system that will meet all the necessary objectives, things like keeping the rain and snow out, controlling condensation, and providing space for insulation.

The cathedral ceiling, part one

For various projects during the last few years, I've purchased bundles of cull lumber from Cub Run Hardwoods in Cub Run, KY. These bundles consist of 600 to 800 board feet of 1 inch thick lumber in various widths that they cull out for various reasons while operating the mill. It's great lumber and a good deal ($100/bundle) for barns and other buildings. Some of the boards are not usable, but usually most of the bundle is nice lumber, maybe with a blemish or a couple of knots. The bundles are made up of whatever species of wood they are milling at the time. Often, there is a mix of woods.

I purchased several bundles last summer and sorted through them, separating the ones that were potentially acceptable for use in the house. One of the uses I had in mind was the cathedral ceiling. After drying about 800 board feet in my greenhouse using a couple of box fans to circulate the air, my dad helped me to plane them to the same thickness (7/8"). We primarily planed only one side (some were thicker and were planed on both sides) since only one side is to be seen -- that inside of the house. We stacked these planed boards on the shed side of my garage where they waited until a little over a week ago.

I cut these boards to 4 foot and 5 foot lengths (they varied in length from 8 to 13 feet). These shorter lengths fit what I need for the ceiling, and they are a lot easier to work with than longer lengths. I set up a 9 foot fence on the table saw and squared the edges, trying to remove as little wood as possible in the process. After squaring the edges, I put a stacked dado head blade in the table saw in order to cut a rabbet on the edges. After about two full days of work, this is what I had:


The boards stacked on my trailer.


Stacked in the frame ready to be tarped.


I alternated the boards to calculate their total square footage.

I had almost half of the boards I need completed. I need to plane more that are dry for the rest of them. That job is waiting for either my new planer knives to arrive or the ones I sent off to be sharpened to return (they were quite dull).

I decided that I would put the boards I had completed on the back section of the ceiling on Friday. I used a framing nailer with 2" nails to attach them to the frame purlins. The boards' length allowed them to span across three purlins. They butt up against one another for each row on the purlins. This worked well since they are of various widths. Here's how it turned out:








There are several different species in this ceiling. As near as I could tell, there is oak, maple, hickory, and locust. The different colors and shades of the wood work well together with their random placement.



This is the view from on top looking toward the west. You can see the joints between the rows of boards. This side of the boards was unplaned except on a few of them.



This is the view off of the other corner toward the east. I thought it was pretty, so I'm sharing it.

It really didn't take long to nail the boards down. Yesterday, I put some 30# felt on the top of the boards to help keep rain water from staining them. I hope to have the front slope of the roof put on within the next two weeks. It'll depend upon when I have sharp knives for the planer.

Eye injuries and the Great Smoky Mountains

Alas, it has been several weeks since I last posted to my blog. It was a lot of work getting ready for the raising and then getting the frame completely assembled after the work on Labor Day weekend. It was great though! I had as my goal to get the roof on before the end of September. At least in the theoretical sense, it was an achievable goal. However, it didn't happen. I can explain why, of course.

In order to get the roof on, I needed to do several things. First was to get the boards for the cathedral ceiling prepared. This involved edging the boards I already had planed and cutting a rabbet on the edges in order to lap joint them on the frame. After that was completed, I needed to build a framework to hold the metal roof at least 14 inches above the ceiling boards (gotta have room for the blown in cellulose insulation). Then, the metal roof could be put on. So, naturally, I started at the beginning by beginning the work on the ceiling boards.

At this point let me offer some important advice: when using a table saw, wear eye protection.

I had barely begun the process of edging the ceiling boards when I wished I had taken my own advice. A piece of board chipped off of the edge and hit me squarely in my left eye. Had I been wearing the eye protection I knew I should be wearing, I would've been fine. But, I wasn't. My eye was injured. It hurt. A noticeable indentation or scratch (corneal abrasion) was left across the pupil of my eye and my vision was blurred because of it. Since my left eye has been my dominant eye, the blurred vision affected what I felt comfortable and safe doing. Driving and using the table saw were two things I wasn't comfortable doing for a couple of weeks after the accident. Currently, six weeks later, my vision is still affected, but I have adjusted so that I am able to do things that I did not feel safe doing in the first couple of weeks after the incident.

So, I didn't get very far on the roof. Then, at the end of September, my family and I left for a week long visit to the Great Smoky Mountains National Park. We rented a house and spent a week there three years ago, and the children have wanted to go again. So, we saved some pennies and did so. We stayed in a nice house near Cosby, TN, which we rented through Smoky Dreams Cabins (very nice). We visited several areas of the park and walked a few miles on trails to see some of the old buildings they've preserved in the park. We had a great time.

Here are three photos from our trip: