Building the Woodshop: Part VII - Framing the Roof
The idea is simple enough - all you really want is to shed water and hold heat in, right?
When I was designing the shop, I investigated several different methods for constructing a roof. First was manufactured trusses... I ruled those out because I knew I wouldn't be able to place them myself. Another option was to use wood I-beams... This was a really tempting option, and now that I've finished, this is the route I would take today, if I were to do it over again. Finally, I looked at doing it "old school" - with honest to God 2x10 rafters.
I didn't have any real reason for going that way except so I could say I did... a bit of a romantic notion, I think, of older methods. I hadn't built anything with rafters for a while and was itching to try out my new Milwaukee circular saw, which I treated myself to as part of my savings for doing all the work myself. My old saw has been dropped one too many times, and while it still works, it's just a little "shook".
The beauty of having a cad program is the ability to draw out and measure each cut accurately in the ether that is the computer. Once upon a time, I actually knew how to use the rafter tables on the side of the framing square, but lack of use has sent those memories into their own ether. My final plan was pretty simple:
In order to picture the individual members of the roof better, here's a perspective view:
The collar tie keeps the two sides of the roof from spreading - and the v-shape ties the center of the collar tie to the rafters so drywall can be hung off of it's bottom without sagging in the center. According to the rafter span tables, it could be done - so long as the wood for all of the members was #2 and better Hem/Fir, a common grade/species out here. I started by crowning the lumber - marking the high point of any curve on the lumber, so when you cut the rafters you can place the curve up. Then it was laying out and cutting the rafters for the lean-to portion of the roof and setting them in place one at a time:
One main difficulty was going to be the rafters over the main portion of the building. First, I looked into some scaffolding, but that was going to push the budget too much, which was already strained from the extra costs incurred because of the foundation. So - I bought some 1x4, took some 2x4's I had extra, and built my own using spare 2x10's for the planks. It's not something I would recommend for anyone - and it's certainly not an approved method, but it got the job done for me.
Now that I had scaffolding (of sorts) the big trick was going to be setting the initial rafters. The building is 36 feet deep, and the longest 2x12's I could get to use as a ridge beam were 16' long - which is 4 feet short, as you can see in this photo:
The scaffolding was actually much more stable than it looked, fortunately. One of the main objectives was for the design of the roof to be completely build-able by one person - which I'm proud to say I accomplished - but it wasn't without a bit of a struggle. This is where the struggle came in... I had a pocket built into the wall to hold one end of the ridge beam, and I thought I would just use a board to prop up the end of the ridge beam. Works well in theory, but not so much in practice. I would prop up the ridge beam, pick up the rafters which would slide off of the wall at just the moment I was ready to nail them. So, I placed a clamp on the bottom of the rafter to stop it from sliding. On my next attempt, the prop I was using would get in my way - I could put one side up, but without the opposite rafter to push on it from the other side, it wouldn't stay in place.
I ended up balancing the ridge beam on my shoulder and picking up the ends of each rafter, all the while holding a pneumatic nailer in my right hand. Once I got all three into place, a quick shot from the nailer on each side was enough to hold it up while I finished nailing it.
Whew! That was enough to get me going. Fortunately, my building skills hadn't completely evaporated from disuse, and the two ridge beams lined up with each other perfectly - though they were about 1" further apart than they should have been. To pull them together, I looped a 1/4" nylon rope between the two peaks and using a board, I wound the rope like a rubber band, pulling the two ends together. When they were the correct distance, I nailed an 8' long 2x2 centered on the opening on the bottom of the two ridge beams spanning the distance. From there, it was just placing the remaining length of 2x12 ridge beam between.
Lots of people asked me if that was safe - how can you have a ridge beam that is essentially three pieces? Truth is, the beam isn't structural. If you wanted, you could nail the rafter to each other without a ridge beam - it's only real function is to give you something to make aligning and nailing the rafters up easier.
With the rafters in place, I built a base for the cupola - which is a fully function vent. I'll build the frame of the cupola on the ground and place it later in the process...
Finally, the roof was taking shape. Here's an interior shot with all of the rafters up and in place - notice I haven't put the gussets onto the web and collar tie yet - that's something that can be saved for later work, as for now my main focus is to get the roof on and have it shedding water before the rain season sets in.
One thing I love about where I live is there are definite seasons - and one notable part is their predictability. From after the 4th of July until mid-September, one can count on very few rainy days. But there's also a fair amount of heat... and it was the second week of august, traditionally the hottest part of the year. Something about working on a roof -it either happens mid-winter, or mid-summer - when the weather is at it's extremes for hot or cold... I guess I should just be happy I for the lack of rain...
Next up was the sub-fascia and the lookouts for the overhangs on the gable ends, shown here shortly after the front was complete:
An important note here - the insulation I will be using in between the rafters is going to be about 8 inches thick or so, a "high-density" R-30 fiberglass batt. It's important that there be a least a 1" to 1-/2" air space above that insulation to allow for air to travel from the soffit to the peak of the roof in each and every rafter space. The "ladder" that holds up the fascia at the gable ends will effectively block that air from traveling up on the far ends. To compensate for this, I drilled holes into the ladders that will allow ventilation... I don't have a photo that describes it well, so here's a graphic representation that also allows you to see how the gable end is constructed:
On the back side of the shop, I want to have an overhang to keep things out of the weather, so that means framing up a roof over that area. Staying with the common rafter idea, I first built the header that would run the perimeter of the overhang:
Because the main roof would tie into the roof of the overhang, this needed to be done before sheathing. The beam is a pair of 2x6's with a layer of 1/2" plywood sandwiched between them. The rafters themselves are also 2x6, with a hip on each corner:
There is an interesting corner that I need to deal with right where the hip on the right side in the photo above meets the main roof - which I don't think I did as well as I should have. I thought and thought about it, and in the end decided I was thinking too much and just built the thing - in the end I think I should have thought about it more, but time was getting more precious. Something I haven't brought up before was during all of this, I was also the primary caregiver for my dad, who had Alzheimer's that was getting more severe daily it seemed... Up to this point in the construction, I had been able to spend an hour or two at a time working on the shop without checking on him, but that was getting tougher to do. But I will get more into that in the next installment...
Once all the work was complete with the rafters, I could take apart the "scaffolding" and re-assemble it onto the east side of the shop for the next phase of construction, sheathing and roofing:
Which was good, because August was now half over and I wanted to get the roof on by or shortly after Labor Day to avoid the rains - and Labor Day was only a couple weeks away.
Look for the next installment of this series - Roofing -coming soon!