How many rolls of duct tape will hold my house up?

[meeks]

Everyone knows that lamination is the key to structural strength. Lately, they are making beams out of plywood. For example, they make a 2 inch thick 12 inch wide "plank" that is supposed to be stronger than a 2X12 board. I see these things being used in a lot of places these days.

So, if they can hold up a house with strips of shaved wood that are less than 1/8th inch thick, why not laminate duct tape. I want to create a beam capable of supporting an entire house, and made entirely of laminated duct tape.

Are there any scientists out here that would know how to determine the amount of layers, width, thickness, and final dimensions of the beam? Also, how many rolls of tape would be needed? The beam needs to be

40 feet long. There will be one center post at exactly dead center (20 feet). The house will be a two story home, 24 feet wide and 40 feet long. This beam will support the center of the home, with 2X8 floor joists resting on this beam, with structural walls down the center of both the first and second floor, up to the peak of the roof. The ends of the beam will sit on a poured concrete foundation. The center upright post will be a steel column, however, a duct tape post is also an option I have considered.

Meeks

[stretch]

Even if the rubber based adhesive in duct tape would hold mup for 20 years without drying out (It won't), the tape itself is not rigid enough to hold anything significant as a beam.

Stretch

[Calvin Henry-Cotnam]

Even if duct tape had the rigidity to be useful as a beam (I doubt it), using it for a post would be out of the question as it would have to be non-compressible to hold up as a post.

Tension loads and compression loads are two very different things.

[Mark]

Why in the world would you doubt such a thing ??

[barry]

Strength of materials has been a focus of study for many for a long time. Wood is a very interesting composite material itself, with sawn lumber having very different properties from the various laminates. (Ever try to split a piece of plywood?) What is important here is the orientation of the fibers in the layers and how they're bonded.

When done properly, you can build very stiff, strong structures like the DeHavilland Mosquito or the "Spruce Goose." Or PT-Boats, minesweepers, Skimmars.

Duct tape really doesn't even work very well for taping ducts.

Have you considered spaghetti? "Pasta post & beam" maybe? Certainly better in compression or beam.

John

[Duane Bozarth]

This is a question for Red Green...

[BobK207]

A quick set of calcs gives a beam depth of about 32". I would reccommend against it though, I think you'd have a very hard time getting it passed by the building dept or getting an engineer to stamp your plans

Forget about a DT post unless you wrap a 6" diameter shipping tube with many layers.

Duct tape has a lot of uses, some reasonable, many not. This set of contemplated uses is not .

Stick with wood as basis material for you construction; either sawn or engineered. Floor trusses might be an option.

cheers Bob

[Chris Lewis]

According to BobK207 :

You've obviously never seen Red Green.

Have you ever seen a gadget that would allow you to change tires on a car while the car is moving? Red Green has done it with duct tape.

My favourite: an elevator built out of a hot water tank, telephone booth, some rope, pulleys and duct tape.

[Goedjn]

Yeah, but you can fake compressive-strength by constraining things that are strong in tension. That's how inflatables work. So you make the top half of the "beam" out of long tubes of duct-tape rammed full of more duct-tape with a mechanical press. Flip the thing over to get a reverse camber, tape stub-outs made of complete rolls to the (now upper) surface, and string duct-tape cables along that, along the stub-outs.

So it's do-able, just stupid.

[Duane Bozarth]

My take has always been there's virtually always far more to the structure than is shown, but it is a hoot...

[Robert Allison]

I forwarded your question to our engineer and this is what he told me:

Due to the inability to predict the actual construction methods used to construct the beam or the capabilities of those constructing it, he would have to build in a safety margin far greater than he would ordinarily do for a standard construction beam. That said, he advised using a double 2x12 beam as a form to start with and wrapping it with layers of duct tape to achieve a uniform depth of 19'- 7" and a uniform thickness of 8'-7". He will assume no liability or warranty for actual performance.

[nlbauers]

Obviously, if you are using the good stuff, it will take less. That Home Depot 3-rolls-fer-a-buck junk is gonna take lots more, and you will see significant delamination over time. My cousin used duct tape as earthquake strapping for his So Cal home, and was real happy with the results. It took him about 17 rolls cause it was a two story house with a basement, and of course, he ran each strap under the foundation and then up over the roof and all.

Good luck, Neil

[Mike O'Donnell]

I heard this several years ago, but it seems appropriate with the recent Star Wars release:

Duct tape is like the Jedi Force. It has a light side, a dark side, and it it can bind the universe together.

As a side note, my brother in law, who was involved with auto racing (his dad worked for Champion) always referred to the stuff as "Racer's Tape" since the drivers used it for quick repairs in the pit during the races.

Mike O.

[Jimmy]

Not all duct tape is created equal. Compare the stuff Lee Valley sells to the stuff at your local hardware.

[tm]

A friend of my nephew's sister-in-law used duct-tape as an iud.

[wdude]

One. If it's large enough.