The 78 step side I bought to upgrade the 03 Ranger sounds pretty badass and moves when told. Subsequently, it doesn't like to pass gas stations.
I love a good hot rod. Just like I love kids. They're both fun to watch and be around, for a while, and it's really nice when they go home with those in charge of them.
Said another way, I like my 6 cylinders. With gears, they get everything done the big boys can (just like the big trucks do). They just don't do it as quick. My old 69 had no trouble breaking 22, and that was before radials, throttle bodies, understanding about the advantages of cold air intake. . . .
To placate myself, there is a 78 250 inline 6 in the bed of my truck. I already bought an engine stand and a over-engine "creeper" that eat a bit of coveted shop floor, so I didn't want to add a cherry picker to the mix. Instead, I wanted to opt for a hoist.
With that hoist thing comes the, "you can't even store much up there, because the trusses weren't built for it" thing. Just a glance at the plates joining the 30 2x truss components makes clear that fact.
On the shop side of the garage-shop, I went over the tops of all the butt joining plates with 3-1/2" x 36" 3/4 ply, on both sides. I swapped the 2x that ran across, say, 12 trusses, to stop lateral movement for two sheets of 1/2" ply and a 1,000,000 (give or take 5) screws. They are better than well joined now, and even share a bit of the load with each other. There is a second 1/2" sheet over the center of those two sheets.
That has worked well for storing holiday stuff, fans, heaters and other light things.
Here, I'm going to be lifting a 600 pound motor. As such, I'm doing a whole lot more beefing up of joints. For example, those V like joints get plates too, and their tops get plates. All of it on both sides of each 2x truss.
Yesterday, I was eyeballing some plywood I earmarked for a project I abandoned. The 8' x 10" pieces got cut in half and an angle matching the ceiling cut on one end. This, as luck would have it, allowed me to position all of them closer to the hoist point and beyond the mentioned added plates.
Another straw on this camel was, I laminated, 5 pieces thick, pieces of OSB to make a glue-lam, of sorts, 12' long. it mounted vertically, and is tied to each truss too.
Oh, and this seemed like a good use for some of that LARGE roll of plumbers tape I scored at a yard sale. I wrapped it, under tension, around the wannabe glue lam and the truss connection points.
In the end, a whole lot of that OSB I rescued a couple years ago got put to good use, and I have some room back in the garage side for those mentioned auto toys.
When all is said and done, just for a bit extra overkill, I'll be using a couple of those 2x's on both sides of the pickup and between the concrete floor and the trusses.
With all this comes some interesting education. I didn't know squat about hoists, chains. . . . Just shopping took me down a whole bunch of rabbit trails.
From the get go, I learned chain as thin as 5/16 can be kick butt, if it's the right kind. I admit, this made me all sorts of skeptical, but research showed it to be true. However, it was only true if you got the right 5/16" chain.
I learned there is grade 30, grade 47, grade 70, grade 80 and grade 120 chain. Only the last two are to be used for hoist work. Others, generally, state, in clear terms, NOT TO BE USED FOR HOIST WORK.
You'd think, since the 70 is only 7% less able than the 80 in indicated weight capacity, you could just switch up to 3/8", grade 70 chain to do what the smaller grade 80 does. That turns out not be true, according to a whole lot of folks more knowledgeable on such things than me.
That 7% difference comes with changes in the make up of the chain. The 80 is an alloy, unlike the lesser grades that are, often, heavy in carbon, so prone to snapping. All other things being the same, the 80 and 120 are far better suited to be used to hoist heavy things. Safety being one of the main reasons.
It can get confusing when you're shopping for grade 80 chain for hoist projects. Many list their chain as grade 80, but promote them for tying down that big dirt working rig and such. You'd think more than do would make clear for those of us ignorant of that world grade 80 is grade 80 and everything else is just how they advertised their wares.
Then we can look to the hooks and links to tie things together. It stands to reason, and is true, you don't want to use a grade 70 hook or link on a grade 80 chain. It isn't going to blow up or anything, but it does make that hook or link the weak point.
Once all the other is aside, I find myself shopping for links. That gets confusing too. What shows up over and over is, tow chain connection means. You may have to dig a bit to find, for example, Hammerlock Mechanical Connecting Links, for joining chain pieces.
NOW, if only I could lower the floor a bit, in case I ever have to load the long bed joiner, bandsaw, tablesaw. . . .
I built up some box beams, 2x4 top/bottom plates spanned by OSB glued and nailed every inch. Supposed to handle a lot of weight as the tension is in the 2x4's and the shear is in the OSB. My shop rafters were sagging a bit so I spanned those beams across the 24' of wall and sistered them to the rafters lower span after jacking up the rafters back to level. The beams didn't budge a bit. Also made one 30" tall to span the opening over my 16' door to help carry the load.
You don't have to worry about all the math when you just buy a 1 ton chainfall. That's all you need for that engine. I have used a lot of chain falls over the years. Over loaded a few of them. The chain never failed. The gears inside fail first or you open the load hook a bit. The Old models had bigger heavier chains compared to the new models.
So is the goal to hang the hoist from the beam you added that goes perpendicular to the bottom chords (the bottom of the trusses)? I am not an engineer but I do not think that much of the load will be transferred past the first pair of joists, at least not unless those joists start to fail. From what I remember while researching whether I could (should) hang a hoist from my garage ceiling, the web (diagonals) that connects to the bottom and top chords are normally in compression and by hanging significant weight from them you may be changing that to tension. If I understand it, that means that instead of the bottom chord supporting the roof, the roof is now supporting the bottom cord which it is not designed to do. My 2 cents.
--Nathan, TX. Hire the lazy man. He may not do as much work but that's because he will find a better way.
Your points are sound, and reflected in the plates used on the trusses.
Some of the pressed in plates on both sides of the trusses are as small as about 3" by 4", so don't do much more than hold the trusses together during shipping, and limit lateral movement off the 2x its against. Thus the many plywood and OSB plates (I have a siding/coil nailer making generous use of nails easy).
I did far less on the shop side, where I installed an attic ladder and plywood flooring to allow storage of lightweight items (e.g., heaters, fans, tool boxes, holiday decor, empty boxes. . . .). Over ten years in and even with a 200 pound guy tramping around, all appears to remain well with just the adds of plates over the horizontals and swapping 2x's tying all the truss bases together for plywood (and hundreds of square drives).
On the hoist, the glue-lam ties to 7 trusses, with the hoist in the center. Even before being tied together, there was zero gap between the laminated flatstock and the truss bottoms. The lam got 3" screws to horizontal and vertical, to secure the position, then tensioned plumbers' tape wrapping it and the verticals it tied to.
There was a hugely notable difference in the behavior of the bottom truss 2x just from tying the lam. Adding sandwiched ply vertically was even more impressive.
Ideally, I'd sister 2x6's, or even secure 1/8" metal straps, screwed every 4", to the bottoms of the 2x's (think cable bridge - the metal doesn't stretch and bend like wood, so what would be about like adding two 2x6's or 8's, BUT would be fun to deal with when the rock went up.
Not visible, because they are temporary, used only when lifting, are ground to ceiling (under trusses) 2x's. I may grab a couple fabric/cyclone fence posts and set up a swivel mount for them on the ceiling. Labels on the pipes would help me remember what they do after a coffee break. ;)
Webbing: Feature a dense, continuous pattern of smaller triangular web members (often made of 2x4 lumber) throughout their entire structure. This configuration efficiently distributes the roof's weight and forces to the exterior walls.
Open Space: Lack significant open space. The internal webbing obstructs any potential for a usable room or even easy movement and storage, which is why converting a standard-truss attic is difficult or impossible.
Purpose: Designed solely to support the weight of the roof deck, roofing materials, and environmental loads (snow, wind).
Appearance: The numerous internal members give them a very "busy" or complex appearance compared to the open center of attic trusses.
Attic Trusses (Room-in-Attic Trusses)
Open Space: Possess a large, clear span area in the bottom center, which is the designated space for a room, storage, or mechanical equipment.
Webbing: The triangular webbing is present, but it is confined to the sloped sections on either side of the open space (above the kneewalls).
Structure/Size: They are engineered with larger, heavier timber sections for the top and bottom chords to support the extra dead and live loads of a floor (e.g., furniture, people) in the attic area, unlike standard trusses.
Appearance: Visually distinctive due to the large, empty middle section, clearly defining where the floor of the attic room will be.
In short, a glance at the internal structure will immediately reveal the difference: standard trusses are filled with triangles, while attic trusses have a large, empty rectangle in the middle.
A standard 8-foot 2x4 can handle approximately 1,000 pounds (about 450 kg) of downward pressure when standing on end, with some sources citing even higher figures for stronger wood types. However, this is a general estimate, and the actual load capacity depends on the wood's species, grade, length, and how it's supported, with longer spans or weaker wood being less capable of holding a load.
Corelz125, it's mind boggling to think of all the different chains I've used over the years, most of it very heavy stuff, but that has limitations, then see what is used on a 2 ton hoist (5/16"), because of the difference in material composition and how its made.
I can see why many complain when grade 80, or what have you, isn't labeled.
Top cords are in compression, pushing out towards the walls. Bottom cords are in tension, trying to be pulled apart by the ends of the top cords. The webs will alternate in compression and tension depending on where and how they’re installed. These keep the top and bottom cords rigid and from bowing away and losing strength…beams are strongest when they’re under compression and tension along their long axis. Those metal gusset plates are there to keep members aligned, as you noted, but the wood does all the work. The extra wood gussets you added will help considerably with reducing twisting due to any overloading.
The issue with adding too much load comes from the dimensions of the material used in the cords themselves, and their lengths, how they’re supported at the walls, etc. Pre-fab trusses like those are engineered to translate a specified dead load, and live load, from the roof to the walls, which carry it to the foundation and then to the ground. They’re usually way over engineered and, as long as you never side load them, you should be fine…but I’d wager an engineer would tell you they’re not rated for what you’re doing. The purlin you’ve added across the bottom cords serves to tie them all together and further distribute the load among the trusses. One truss is weak, many trusses are strong.
My only concern is that you’re adding a compressive load to the bottom cords, which want to be in tension. Again, I think they’re probably strong enough to handle it, especially with the gussets that have been added but it’s not, technically speaking, proper. You’d rather have the load attached to a ridge beam in the middle of the top cords. That way the load follows the natural compressive path downwards. The load you’re adding is transient, and (shouldn’t be) a shock load, so the trusses should be able to absorb it with the modifications you’ve made. If a compressive load were to overwhelm the tension load on the bottom cords, it would change the orientation of the load distribution of the webs, which could cause them to pull apart…again, your wood gussets should help with that. Did you add them to the top cords as well? You might consider that.
I’m not an engineer, but I know some stuff about trusses. If you want to reinforce that purlin you added, get some Simpson hurricane ties to tie the new purlin to the bottom cords. That’ll insure they never shift or pull apart as you add a transient load with the hoist. You need a solid transition from the purlin to the cords to insure load distribution, since you’re kinda loading it in the wrong orientation. And NEVER drill holes in cords or webs of pre-fab trusses without an engineer doing calcs for that…pre-fabs are designed to be light weight, and inexpensive, so they’re not as over-engineered as a cut and stacked roof.
Ryan/// ~sigh~ I blew up another bowl. Moke told me "I made the inside bigger than the outside".
I suppose the proof will be in the pudding. I would tie a plumb bob to one of the nearby bottom cords with the point just touching the floor. If it drops even a little with weight on the hoist, I would back off and reassess.
--Nathan, TX. Hire the lazy man. He may not do as much work but that's because he will find a better way.
Note the temporary beams, or metal poles (a choice if it will be used a few times, vs just once), under the bottom board for the rare lift. The bottom 2x cannot deflect. In part because of the lam beam tying 7 truss bottoms together.
The string and weight would be a good idea, if only to test, or just to monitor against permanent damage.
Ryan, I did want to grab some ties, but town is a literal hour away.
In the meanwhile, I did tie the laminated OSB to the trusses via plumber's tape (way overlapped). I used an awl to put tension on the tape as I worked around the install, so there shouldn't be even 1/8" of shift due to compression, under load.
Nail holes aside, there are none.
If nail holes are a concern, it would seem truss companies would tell roofers how many they can use when tying plywood/OSB to them, or how many framing nails are allowed when 2x's are added to stop lateral movement, but none of the engineered trusses I ordered in the past had that kind of information.
In the end, since I will be going down this road one way or another, the more I can do to over engineer things to put the least amount of stress on the package deal, the better. Accordingly, the thoughts, concerns and ideas are appreciated.
