Author Topic: how far is too far? - building a scaffold platform  (Read 792 times)

nereo

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how far is too far? - building a scaffold platform
« on: July 18, 2017, 03:09:57 PM »
I plan on replacing some siding about 9' off the ground.  I'll set up pump jacks to do give me a nice work platform.

Challenge now is to span ~10 feet between the two jacks so I don't have to move them around (or get a third).  A quick look at aluminum scaffolding platforms made my eyes bleed (~$250 for a 20" x 12' platform). 

Thinking instead of building a 20" x 12' platform out of two 12' 2x4s, cross braces every 16" OC and 1/2" plywood for the surface.  There would be a 1' overhang on each end, but would it flex too much in the middle? I'm favoring this approach over two 12' 2x10s...

This will be light duty - supporting just me and some hand tools - 200lbs or so.  Ladder jacks are rated to 500lbs, so my only question is the platform.  Here's a video to give an idea - my design would be similar only with more frequent 'ladder' rungs (cross braces) and 12' instead of 8'.
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paddedhat

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Re: how far is too far? - building a scaffold platform
« Reply #1 on: July 18, 2017, 06:22:51 PM »
I used to have a few of these around. I made mine with a 2x12 with 2x4 runners, on edge, nailed to the bottom. You should be fine. Use some gorrilla glue on the plywood, lots of 8D nail, put a glue block at the ply joint and glue and nail it well. Use the prettiest, most straight grain, knot free 2x4s you can find. Don't let more than one person on at a time, and give it a test run before you use it. Prop it up on some cement blocks and give it a few trampoline bounces. Deflection is expected, OTOH cracking, ugly noises, splintering, laying face up wondering what happened, not so much...

And all the usual disclaimers, may cause user injury, don't try this at home, blah,blah..........................

nereo

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Re: how far is too far? - building a scaffold platform
« Reply #2 on: July 18, 2017, 06:58:36 PM »
THanks for the response.
It seems like something that *should* work just fine, but wanted the input before I went ahead.  $250 for a 12' aluminum platform or < $50 to build one (and I'll reuse all that lumber later).  Yeah it'll be a lot heavier but I only have to set it up once...

Of course I'll test-bounce it before going 8' into the air.
Thanks.
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Capt j-rod

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Re: how far is too far? - building a scaffold platform
« Reply #3 on: July 18, 2017, 08:03:44 PM »
I'd go up to 2x6 and try to find yellow pine rather than spruce... USE SCREWS!!! nails pull out. A little liquid nail never hurt anything either. Safe is always better than sorry. Remember the cost of your insurance deductible when budgeting these things.

Fishindude

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Re: how far is too far? - building a scaffold platform
« Reply #4 on: July 19, 2017, 07:37:00 AM »
Most rental houses have the nice aluminum pick boards for rent pretty cheap.

paddedhat

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Re: how far is too far? - building a scaffold platform
« Reply #5 on: July 19, 2017, 08:09:12 AM »
I'd go up to 2x6 and try to find yellow pine rather than spruce... USE SCREWS!!! nails pull out. A little liquid nail never hurt anything either. Safe is always better than sorry. Remember the cost of your insurance deductible when budgeting these things.

Stop with the "SCREWS" drama.  plywood nailed to framing lumber, with a tight pattern of 8D cement coated sinkers is not going to pull out in your lifetime.  Ever try to disassemble anything like this? Doubt it. If the goal is to reuse the lumber, it's hardly worth it to save $8 bucks in 2x4s if you waste $8 in screws to do so.  BTW, there are times when screws are a lot more dangerous than nails, since they tend to snap under shear loads. I have seen a staircase collapsed and fall two stories, with a person on it, since the 1/2 dozen large deck screws attaching it to the second story header all failed in shear. My local building inspector made a homeowner completely disassemble and rebuild a new deck, since the guy did all of his structural framing with various sizes of deck screws. The pretty colored deck screws you buy at the big box stores are not structural, they are brittle, they snap and shear without warning. All these characteristics are the exact opposite of how nails perform.

Fishindude

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Re: how far is too far? - building a scaffold platform
« Reply #6 on: July 19, 2017, 08:14:20 AM »
Stop with the "SCREWS" drama.  plywood nailed to framing lumber, with a tight pattern of 8D cement coated sinkers is not going to pull out in your lifetime.  Ever try to disassemble anything like this? Doubt it. If the goal is to reuse the lumber, it's hardly worth it to save $8 bucks in 2x4s if you waste $8 in screws to do so.  BTW, there are times when screws are a lot more dangerous than nails, since they tend to snap under shear loads. I have seen a staircase collapsed and fall two stories, with a person on it, since the 1/2 dozen large deck screws attaching it to the second story header all failed in shear. My local building inspector made a homeowner completely disassemble and rebuild a new deck, since the guy did all of his structural framing with various sizes of deck screws. The pretty colored deck screws you buy at the big box stores are not structural, they are brittle, they snap and shear without warning. All these characteristics are the exact opposite of how nails perform.

This is 100% accurate.
Screws are way over used in the construction trades.


nereo

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Re: how far is too far? - building a scaffold platform
« Reply #7 on: July 19, 2017, 10:07:14 AM »
Most rental houses have the nice aluminum pick boards for rent pretty cheap.

True - my problem with rentals is that I tend to work only on weekends, and even a 'simple' project like this could easily stretch across 3 of them do to "life".  So I'd rather built something I can leave up, then dismantle and reuse the lumber than fork out roughly the same amount in rental fees.  If/when I'm really focused I'll do the pick-up on Saturday, return on Sunday - but that's not this project.

Good info re: screws. Side topic but I'd love a primer on various fasteners and their strenghts/weaknesses.  E.g. deck vs. wood, when/if i should use those 'spiral' framing vs straight.  I get galvanized provides rust protection but are there times hwen "bright" nails are actually better?  Anyone know of a good source to reference - those guys at my big-box store don't seem to konw very much in this department.
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thesvenster

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Re: how far is too far? - building a scaffold platform
« Reply #8 on: July 19, 2017, 10:09:33 AM »
I'd go up to 2x6 and try to find yellow pine rather than spruce... USE SCREWS!!! nails pull out. A little liquid nail never hurt anything either. Safe is always better than sorry. Remember the cost of your insurance deductible when budgeting these things.

Stop with the "SCREWS" drama.  plywood nailed to framing lumber, with a tight pattern of 8D cement coated sinkers is not going to pull out in your lifetime.  Ever try to disassemble anything like this? Doubt it. If the goal is to reuse the lumber, it's hardly worth it to save $8 bucks in 2x4s if you waste $8 in screws to do so.  BTW, there are times when screws are a lot more dangerous than nails, since they tend to snap under shear loads. I have seen a staircase collapsed and fall two stories, with a person on it, since the 1/2 dozen large deck screws attaching it to the second story header all failed in shear. My local building inspector made a homeowner completely disassemble and rebuild a new deck, since the guy did all of his structural framing with various sizes of deck screws. The pretty colored deck screws you buy at the big box stores are not structural, they are brittle, they snap and shear without warning. All these characteristics are the exact opposite of how nails perform.

Whoa that's really interesting. And really good to know.