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re: greenhouse plastic prices
25 jun 1996
carl steen wrote:
>i note that nick pine has been quite helpful in posting
>prices on various clear plastic films for greenhouse structures.
that's me, helpful :-)
>does anyone have access to mail order or bulk orders for these films?
you can order them from lots of greenhouse supply places, eg stuppy at
(800) 877-5025, or geiger at (800) 4geiger, ecgsales@hortnet.com. uv-treated
polyethylene greenhouse film comes in folded rolls from 14' x 100' up to
about 48' x 160' long, the latter weighing 232 pounds and costing $552
in geiger's catalog, in a 0.006" thickness.
>he states about 3 year life for 5 cents a foot polyethylene
that's the guarantee period. at plastics also make "duratherm" with a 4 year
guarantee, 8 mils thick, at about 8 cents/ft^2... these films are easily
replaced and recycled if attached with aluminum extrusion clamps costing about
75 cents/linear foot. plastics account for about 2% of us oil consumption...
> 10 years for 10 cents/ft polyester
that's a guess. that product is not quite on the market yet. look for it
to be distributed by armin and replex plastics, made by bayer and dow.
japanese greenhouses once used this mylar glazing...
>any other comparable materials?
replex 0.020" clear flat polycarbonate plastic is nice. it comes in rolls
49" wide, and has a 10 year guarantee against loss of light transmission
and an expected mechanical lifetime of 25 years or so, at about $1/ft^2.
ge should be making a similar product soon, 0.033" thick, perhaps 48" wide.
then there's single wall corrugated clear polycarbonate available from
replex or sps plastics ("dynaglas") for about $1/ft^2 as well. this might
be good for siding on south sides of houses. my steep south attic roof now
consists of 600 ft^2 of this stuff, which comes in standard size sheets,
eg about 4' x 12'.
another interesting product is e c geiger's 30' wide "northerner" greenhouse,
with a gothic arch shape. here are some heights above ground: 1' from side,
4'5", 2' from side, 5'5", 3' from side, 6'7", 1st purlin 7'10", 2nd purlin,
10'6", ridge, 13'3". all these heights can be increased by 2' or so with
longer ground posts.
and ray onofrio of williams scottsman mobile offices in nj (800)782-1500,
quotes $238/month for a 6-12 month lease on a 10' x 40' x 13'6" tall boca
approved office, divided in 3 rooms, with electric resistance heat, an 8'
ceiling height inside, a half-bathroom, r11 walls and floor and an r19 roof,
with 7 46" x 27" double-glazed windows, 2 on each end, 3 on one side and
2 on the other. these are normally set up on dry cement block piers 8-10'
apart lengthwise, on each side. the normal clearance to ground is 28-32"
after they are blocked and leveled, and the floor joists, etc. take up about
18" here and there under the floor. ray says they can stretch this to 48"
clearance, but it might require some mortar in the piers or footings...
the thermal conductance of that office would be about 100x8/r11 + 400/r11
+ 400/r19 + 7x46x27/144/r2 = 73 + 36 + 21 + 30 = 160 btu/hr-f, so it would
take about 24(5500)160 = 21 million btu to keep it warm 24 hours a day in
our 5500 f philadelphia heating degree day climate, ie 6232 kwh at a cost
of about $750, at 12 cents/kwh. these also have a 6 gallon electric resistance
water heater. plumbing consists of a 3" waste pipe and 3/4" copper pipe
sticking down through the floor.
nick
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