The Angle of your Dangle… ;)

6 Jul

I recently received  an email from a guy who wanted to build a Green roof on top of his ISBU Home.

He’s using SIPs to create his roof. Why? Because he’s S-M-A-R-T. :)

However, “green roofs” are HEAVY. You have soil (sometimes, as Kim pointed out, “engineered” using perlite or vermiculite), sod, planting materials, decking… the water in the soil… the weight of a torrential downpour… blah blah blah…

By the way… thanks, Kim! :)

This is the diagram of what he wants to do.

Green roofs come in all shapes and sizes. The rule of thumb is to divide them into three categories;

  • Extensive – less than 6″ thick
  • Semi-Intensive – 25% above or below 6″ thick
  • Intensive – Over 6″ thick

The actual Green Roof weight can range from about 35 – 150 pounds PER SQUARE FOOT.

That means that even using SIPs, he has to reinforce the roof, to carry the load.

You CANNOT just chuck potting soil up on top of the corrugated steel and expect the earth to act as insulation. That’s ridiculous.

Beyond that, the corrugated steel isn’t designed to be used for that purpose. By itself, it won’t support that kind of load. You’re courting disaster.

You have to build a REAL roof, first.

And even though SIPs (my roofing material of choice) are “Tonka Tough”…

SIPs WILL NOT carry that kind of load without some kind of support.

I suggested he think about building a steel subframe to support his SIPs,  thus supporting the weight of his Green Roof. I suggested that he even explore using “simple” angle iron stock.

Shortly after that, all heck broke loose in my email in-basket.

People started hollering about how “limited” the sizes of angle iron are.

What? I’ve never found this to be true!

Sure, sometimes I have to source a piece of steel stock specific to my requirements, but it’s all good. Steel doesn’t fall from the sky, except maybe at Skyway Steel, where I got that terrific photo!

Here’s a table that will give you some ideas about WHAT SIZES of angle iron are readily available.

Included is thickness and dimensions of the angle iron stock, the weight of the steel per 20′ section and some pricing. Disregard the pricing as steel is moving up and down all the time. When you need the steel, price it locally.

Or better yet, find some to recycle. You’d be surprised what you can find, if you really go look for it.

Angle Iron

 

Wt.

 

Price

 

Price

 

Price

size-1 / 8″x

 

wt20′

 

Per/ft.

 

/10ft

 

/20ft

1/2″ x 1/2″

 

7.6

 

$0.75

 

$5.50

 

$10.00

3/4″ x 3/4″

 

11.8

 

$1.00

 

$5.50

 

$11.00

1″ x 1″

 

16

 

$1.25

 

$6.50

 

$12.00

1-1/4 x1-1/4

 

20.

 

$1.50

 

$8.50

 

$15.00

1-1/2″ x 1-1/2″

25

 

$1.75

 

$10.50

 

$19.00

2″ x 2″

 

33

 

$2.00

 

$14.00

 

$25.00

Angle Iron

 

Wt.

 

Price

 

Price

 

Price

size-3/16″x

 

wt20′

 

Per/ft.

 

/10ft

 

/20ft

1″ x 1″

 

23.

 

$1.50

 

$9.00

 

$17.00

1-1/4″ x 1-1/4″

30

 

$2.00

 

$11.00

 

$20.00

1-1/2″ x 1-1/2″

36

 

$2.50

 

$14.00

 

$26.00

2″ x 2″

 

49

 

$3.00

 

$18.00

 

$32.00

2-1/2″ x 2″

 

55

 

$4.50

 

$24.00

 

$45.00

2-1/2″ x 2-1/2″

61

 

$4.00

 

$23.50

 

$43.00

3″ x 2″

 

61

 

$4.00

 

$23.50

 

$43.00

3″ x 3″

 

74.

 

$5.00

 

$28.00

 

$52.00

Angle Iron

 

Wt.

 

Price

 

Price

 

Price

size – 1/4″x

 

wt20′

 

Per/ft

 

/10ft

 

/20ft

1″ x 1″

 

30

 

$2.00

 

$12.00

 

$22.50

1-1/4″ x 1-1/4″

38

 

$2.50

 

$15.00

 

$28.50

1-1/2″ x 1-1/2″

47

 

$3.00

 

$17.00

 

$31.00

2″ x 2″

 

64

 

$4.00

 

$22.00

 

$42.00

2-1/2″ x 2-1/2″

82

 

$5.00

 

$29.00

 

$54.00

3″ x 2″

 

82

 

$5.00

 

$29.00

 

$54.00

3″ x 3″

 

98

 

$6.00

 

$34.00

 

$64.00

4″ x 3″

 

116

 

$7.00

 

$43.00

 

$80.00

4″ x 4″

 

132

 

$8.00

 

$49.00

 

$86.50

5″ x 3″

 

132

 

$18.00

 

$49.00

 

$86.50

Angle Iron

 

Wt.

 

Price

 

Price

 

Price

size-5/16″x

 

wt20′

 

Per/ft.

 

/10ft

 

/20ft

3″ x 2″

 

100

 

xxx

 

$41.00

$77.50

4″ x 3″

 

154

 

xxx

 

$60.00

$110.00

5″x 3″

164

xxx

$66.00

$125.00

6″ x 4″

 

206

 

xxx

 

$90.00

$160.00

Angle Iron

 

Wt.

 

Price

 

Price

 

Price

size-3/8″x

 

wt20′

 

Per/ft.

 

/10ft

 

/20ft

2″ x 2″

 

94

 

xxx

 

$35.00

$65.00

2-1/2″ x 2-1/2″

118

 

xxx

 

$44.00

$80.00

3″ x 2″

118

xxx

$44.00

$80.00

3″ x 3″

 

144

 

xxx

 

$58.00

$105.00

4″ x 3″

 

182

 

xxx

 

$74.00

$140.00

4″ x 4″

 

196

 

xxx

 

$79.00

$150.00

5″ x 3″

 

196

 

xxx

 

$79.00

$150.00

4″ x 6″

246

 

xxx

 

$100.00

$190.00

6″ x 6″

298

xxx

$125.00

$220.00

Angle Iron

 

Wt.

 

Price

 

Price

 

Price

size-1/2″x

 

wt20′

 

Per/ft.

 

/10ft

 

/20ft

6″ x 6″

 

392

 

xxx

 

$165.00

1 314

As you can see, there are lot’s of options.

Just do your homework and then use your head.

William H. Johnson said: “If it is to be, it is up to me.”

Dedicate yourself to being dedicated to yourself. Think things through until the solution is reached. It’s that self-reliance and self-responsibility that will guide you through hard times.

That is all. End of transmission… ;)

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One Response to “The Angle of your Dangle… ;)”

  1. Kim July 6, 2011 at 7:25 am #

    Hmmmm. Interesting that this post is in my email box this morning. About twelve hours ago I went to check on a friend’s pallet construction building to see how it is coming along. Much to my surprise I found he had hooked up with a mutual friend who is developing a green roof system. I know some things about green roofs; even won and AIA award for one I designed a few years back. Mostly I think they are a ‘charming’ addition to a structure. In our desert climate it is impossible to install one without an irrigation system and while their cooling effect in the summer is well documented, also well documented is how inefficient they are in the winter when planted with the typical succulents, grasses, herbs, etc. In Canada (where God’s frozen people live) they did great research on how to make a living roof efficient in the winter and came up with a planting that excludes all the normal suspects and replaces them with low growing Junipers. There are several varieties of juniperus chinensis that stay lower than 3″ and spread several feet. Since they are evergreen they look good year round and the little air gap between the top of the soil and the lower branches adds to their insulation value. I can see a little building with these hanging over the edges like Cousin It’s hair, could be fun. Interesting and a bit surprising to hear that you have to reinforce containers but it does make sense. I see some problems ahead for the little pallet building that should have simply had a SIP roof. The door frame is beginning to sag and not all the soil has been put on the top yet, let alone the plants or any water. In a good storm even when the whole thiing will be saturated it is going to weigh a ton. Another point is that the soil used is typically “engineered” soil. In the case of the one I designed, we used a soil mix that was dramatically lightened with perlite. Vermiculite works, too. Regular topsoil is pretty heavy stuff. Hope we get to see pics of the container when the green roof is up!

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