Here's what I'm currently working on. These pics are of a pair of heavy rafters I will install right over the present trusses in my shop. Why am I attempting such a strange alteration? In order to gain the headroom to install this: Here is what the trusses look like in the shop: Basically, 5 trusses will be so modified as to allow the roof of the lifted vehicle to go high enough to allow working underneath comfortably. The days when I crawled about on my back and belly, yanking transmissions and differentials in and out are behind me. Simply cannot do it anymore. My wife is going along with it, kinda, like, she knows this will allow me to continue to keep the heaps running, since having repairs done we cannot afford. Nor can we afford a new vehicle. Tell me I'm nuts, someone! Frank
@Shirley Martin At least I get folks' attention! Here's what "went down" today. First, one of the new 2X8 rafters affixed to my "cherry picker". Next, the old fool operating the crane: The process of raising the rafter upwards: The wall end being nudged into it's spot on top of the wall: The rafter held very tightly in place up against the roof structure: Finally, it is nailed in place, the crane removed, and the old geezer, aflame with joints and muscles aching from activity no longer frequent, has retired to the easy chair, eager to install the second tomorrow, and determine if the resulting strength is sufficient to go ahead and install the rest.
My 2¢... If I am reading this correctly, you are going to install 2x8 to reinforce the top chord and then remove the bottom chord, along with any webbing and king posts. This will alter the load path times 5 across the 5 contiguous trusses. A. It is your garage, so any future issues are on you. B. You are doing the work, so any future issues are on you. C. If you live in an area with decent snowfall, you must make arrangements to get that snow off the roof quickly. If it is a shingle roof and at some point needs replacing... be careful. Due to any potential liability issues related to any of my statements, I must say I would not approve this alteration. Other than that.... good luck.
My stepson did something similar to this....he is a car buff and always has 3 or 4 jobs on the go. His has held up now for at least 10 years.
@Harry Havens I appreciate your input, and concerns. However, you have not yet seen the complete proposal, only the feat of single-handedly raising up and securing 14-foot long 2X8 timbers, at age 75. In fact, girder trusses are a particularly attractive roof structure option, as they place no "spreading load" outward on the walls; they support the load all by themselves. Almost. Most codes require "hurricane" reinforcing by steel plates over the ridge and at the top plate/truss juncture. Below are a few pics of my shop building, constructed in Missouri, in 2001. The span is 24', 2X8s used as rafters, 2X8 joists on 4 foot centers, the joists being 2 feet above the wall height. How was this possible? The walls were basically reinforced concrete, 12 inches thick, built by hand-laying rock. Steel reinforcement ran vertically on 4 foot centers, and horizontally on 2 foot centers. The "bond-beam" atop the walls was 12 X 8 inch reinforced poured concrete, this construction easily shrugging off spreading forces given the relatively steep pitch. The mad fool in the last image is me, finishing the roof. I built that fortress working alone, at age 60. Incidentally, There is no snow load here at all. Plenty of wind-loading, though, which interestingly can contribute to reducing roof dead load in many cases. Frank
Today, I completed the install of two 2X8 rafters 14+ feet long (they're HEAVY!), a horizontal cross joist at desired height above floorline, and a 2X10" widget" up at the very top which helps prevent rafter spread. Prepared to slice through the bottom chord of the existing truss at near dusk, my wife prevailed. Wait for tomorrow. I told her the "ballsy" thing to do was cut away the truss right then. I chickened out. Seems I have less conviction regarding my engineering work outcomes than in previous times, or perhaps more procrastination built in causing pause, a hesitation, to view constructively the potential fails of my folly. Tomorrow, it will be. Here's the first completed rafter structure:
@Shirley Martin Patience! Today, we fetched the rest of the beams needed to complete the job. Quite a load, though it looks meager. The overhead rack was given to swaying a bit, I'm certain it would have groaned with dismay were it able to. The longest 2X8s are 16 feet, quite heavy. After loading up and securing them, the pain started to set in. Unloaded, a bit more. Then, I went ahead and cut 2 more rafters to size and shape, and raised and fastened them in place. Right now, I'm bushed, but satisfied I can still "Do It"! Frank
@Shirley Martin So, let it be written! In these pics the remaining trusses may be seen as being much lower than the new horizontal joists, which are of a lighter color. Wood darkens with age. A total of 4 trusses were removed; the sawn-off legs may be seen. The upper portions of the trusses remain in place. As I supported each rafter, I placed several hundred pounds of upwards force on it, while fastening to the existing upper truss member. This ensured tight contact support of the roof structure. Measurement of height to the joists from the floor before and after slicing away the bottoms of the trusses revealed an indiscernible change in roof height. Frank
@Shirley Martin Albeit with a price paid: lots of body pain, which I tolerate as part of the "deal" given me by life. Actually, the last few days have found me reaching and lifting with less effort and pain than before completing the work. Worst part was working high up on the ladders amid my vertigo, which is mild, but unpredictable. Frank
Wow @Frank Sanoica ..just now read and saw these posts. Like Beth was wondering if you were able to finish this ? Very impressive and industrious ..even if you wete not able to finish.