Grommets as drain holes in canvas awning?

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We installed a large retractable awning over the patio a few years
ago. It works well except for one problem. If the awning is extended
when it rains, the canvas gets wet, sags, and a lot of rain
accumulates in the depression. So far, I have caught it before any
damage, but a couple of times a fairly large amount of water had
accumulated.

I am wondering if I should see about installing some kind of drain in
the canvas and, if so, what?

The awning is 20' wide and about 12' deep when fully extended. This is
the company that makes them and ours looks a lot like the ones on the
main page: http://www.alphaproductions.com /.

One time it rained pretty hard. I didn't notice that it was extended
for awhile. When I did, the puddle was a long oval. The length was
about 80% of the width of awning (so about 16'). The width was about
2' at the widest. It was maybe 6-10" deep at the deepest point.

If I assume the volume to be roughly half of those dimensions on
average, I get something like 8' x 1' x .4 = 3.2 cu ft of water. At 62
lbs/cu ft, that about 200 lbs.

I would imagine that it can handle 200 lbs, but what if I am away? It
looked like it could have gotten a lot larger.

My first thought was to install a row of 3-5 small grommets about
6-12" from the end of the awning. I wouldn't think a very big hole
would be needed. I'm not sure how to install them. Aren't they usually
snapped together by a tool that needs access to both sides and a solid
base?

Re: Grommets as drain holes in canvas awning?

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How about just re-mounting it so that one end is a little lower than the other.
It'll drain to that end.



Re: Grommets as drain holes in canvas awning?
wrote:

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Did you look at the link? The front is about 2-3 feet lower than the
back when fully extended. That's more than "a little lower" and it's
not enough.

The canvas is pretty straight when dry. When it rains, it gets heavier
and starts to sag. Once it gets below the front edge, water starts to
accumulate.

Re: Grommets as drain holes in canvas awning?

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As I said, lower one END. So the water that backs up at the edge strip flows to
the end and off the awning. Should be able to reduce the pool to a part of an
inch.

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If it sags even before the water pools, then my suggestion won't work. Unless of
course, you drop the end even further.

A few, maybe useless ideas:

If it is possible to make the canvas tighter in the middle, and looser at the
ends, the water would be more likely to find its way to the ends. Or, you could
figure out a way to add some tight ropes from the top to the bottom under the
canvas. The ropes alone could hold the canvas up, or some firm foam could be
placed between the canvas and the ropes to lift the canvas enough to prevend
pooling. (pool spagetti?) Perhaps ropes from each high corner to near the center
at the bottom, so the lift is at the center where it pools.

Of course, a padded stick prop under the pooling point could fix it, but you
have to remember to put it there, and the wind could flap the canvas enough to
drop it.



Re: Grommets as drain holes in canvas awning?
wrote:

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So that really is what you meant. That was my first impression, but I
figured no one would actually suggest an awning that wasn't level.

If a 2-foot drop over 12 feet is not enough, how much do you think I
should lower one end ort a 20-foot awning. Should I raise one end
above the roof or lower the other end below the top of the window?

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Yeah, like 5-6 feet.

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Are you sure your name isn't Rube Goldberg?

Re: Grommets as drain holes in canvas awning?

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I agree with others that the Grommets may weaken the fabric, unless you sewed on
a reinforcement layer.

Despite the put-down, I'll make one more suggestion.

From looking at the website, it looks like the arms that extend this thing out
are probably not heavy enough to pull the canvas really tight, especially if
there isn't an arm in the center. An additional "stretcher" added near the
center, which could be added after opening the awning, would both hold the
canvas up and pull it tighter in the center, perhaps alleviating the problem.
Just a length of aluminum tubing with ends to allow it to engage the bottom
strip, and wedge in at the top. A chunk of 2x2 would perhaps work for a test.



Re: Grommets as drain holes in canvas awning?
wrote:

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Put down? I was joking. Rube Goldberg is a very funny guy. I just
wouldn't want him designing my awning.

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You'll probably take this wrong, too, but I am not going to go out and
wedge a piece of tubing to stretch the awning every timne I open it.
For one thing, I don't always open it the same distance. It's also on
the second floor. It shades the patio, but it also shades the room
over the patio.

Re: Grommets as drain holes in canvas awning?
"Unless you plan to use stainless steel or any other type of non
rusting
metal, the grommets will rust and eventually eat away at the canvas.
Also
keep in mind, even if they don't rust, you risk the fraying of the
canvas
around the grommets since they are not sewn within the grommet area."

and

"No matter how well you install grommet, it'll compromise the
integrity
of canvas. "

..............................................................................

Guys, **brass** grommets (the cheap hardware store kind) are COMMONLY
used on boat canvas, __under stress__, or at least FAR more stress
than an awning draining a bit of water.  "Weather cloths" (USA term)
or "Lee cloths" (Brit) are the canvas (usually Sunbrella) that are
strung on the lifelines to the sides of a sailboat cockpit to protect
the sailboat operators from (cold) winds and/or spray.  They are
typically strong enough so that sailboaters often use light string to
hold the bottom edge, in case a boarding wave (from the side) strikes
the boat.  That way the bottom edge of the weather cloth comes loose,
so that the (stainless) stanchions holding the lifelines don't
collapse.

**Normally**, those grommets are put through a double layer of
Sunbrella, with maaaaaybe a layer of webbing, but that is because boat
owners like to pull weather cloths TIGHT.  For __weather cloths__,
those extra layers around the grommet are justified.  For water
drainage, no extra layers are needed.

FWIW, MAINsails (which develop enough power to push a 12,000 pound or
more boat at 7 or 8 mph) usually have *brass* grommets (the strong
kind), though some with have stainless grommets (more difficult to
set, but look nicer for the customer who prefers stainless steel).  In
main sail applications, the luft (front edge of the sail) is usually
several layers of resinated sailcloth, and most usually with a stretch
rope sewn in as well.

Hand-sewn grommets for the luft attachment of a main sail are
**reportedly** stronger than set grommets, but to the best of my
knowledge no one makes them anymore (the rings are available, but the
*brass* sleeves that protect the sewing thread from chafe are not).
FWIW, last week I hand-sewed a 1-1/4" tack (front corner attachment)
to a used sail for a customer (to shorten it a needed 2", because the
sail was longer in the vertical measurement than advertised).  It is
time consuming, but the alternative is some expensive equipment that
only dedicated sailmaking shops have.  It DOES look salty, however.
It also took $60 worth of die setting tools, a concrete surface and a
2# hammer.  The only mainsails I have ever seen with hand-sewn
grommets on the luft (leading edge) were OLD sails.

Cheap grommets (without extra layers of awning material) will work
just fine for water drainage.  It is commonly done on certain kinds of
main sail covers which collect rain (which most main sail covers
don't).

BUT, if you're really worried about grommet corrosion, you can unlay
(unwind) a small diameter nylong rope, take one of those strands and
twist itself back on itself to form a small circle, cut a small hole
(Exacto knife) in the canvas, then sew around the rope/hole, one
stitch close (on the outside), the next stitch out a bit, continuing
around the rope/hole until complete, two ropes/holes sewn somewhat
close together, then sewn (kinda) to each other.  Rope handle attach
points on canvas water buckets were once commonly made that way.  I
did it once, just to say I did it.  Now, I use machine sewing and
pressed grommets, or a sewn on canvas handle.

Re: Grommets as drain holes in canvas awning?
On Sat, 27 Dec 2008 09:23:42 -0800 (PST), snipped-for-privacy@aol.com wrote:

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Thanks. Great information.

As you say, I'm not worried about "compromising" the canvas as it has
very little load when not full of water.

Is there anything you know of that I can do without taking the awning
down? It's a motorized unit with spring-loaded arms. I can see springs
and arms flying around the yard. It's also on the second floor.

However, there are four large windows just underneath the roller
mounting housing. I can easily reach the first foot or two of canvas.

You mentioned something about "resinated sailcloth". Is there some
kind of resin I can get that would seal any loose edges if I just
punch a few small holes?

Thanks

Re: Grommets as drain holes in canvas awning?
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If it is Sunbrella (likely) or other acrylic canvas, "open" edges will
fray terrible unless they are covered (i.e. grommet or edge tape), OR
are "heat treated" as or after the edge is cut.  For a one-off repair,
a small soldering iron (25w or 40w, commonly available at hardware and
home supply stores, or electronic stores such as Radio Shack) can be
used to "cut" and heat treat at the same time.  A regular gun type
soldering iron can be used, but with care, for the heat is high and
quick. A small soldering iron would be the quickest and easiest
solution.  Just plug it in, let it warm up, and punch some holes.
However, I'd watch it like a hawk, for "cut and heat seal" edges are
known to come apart sometimes.  .

The edge on Sunbrella, and any non-acrylic canvas, *can* be sewn over
by hand, much the same as hand-sewing a button hole on a shirt, only
it doesn't have to be all that neat.  Time consuming, and you'd need
to wrap your arms around both sides of the canvas, but it would work.
Don't use regular cotton or polyester or uphoulstry thread, as they
will come apart in the sunlight in short order.  Go to a marine canvas
house or awning fabricator and "donate" some money to their "coffee
fund" for a bunch of outdoor thread, and maybe some sailmakers
needles.  A sailmaker's palm (about $20) is a good idea as well,
though you may be able too get by with heavy leather gloves, or hold a
piece of soft wood in your hand.

What also *can* be done is to use regular sewing Dritz Fray Check,
though I'd watch that like a hawk as well to make sure it doesn't
fray.  (I don't know how Dritz stands up to sunlight.  FWIW, many
resins don't like sunlight at all, with the final surface painted for
sun protection.)

If I could get the awning down, I would use cheap brass grommets.  If
I couldn't reasonably get it down, I would use "button holes" as my
first choice. The "heat and punch" of a small soldering iron -- though
the quickest -- might be cause for concern longer term.  If I wanted
to use this last, I'd probably call a couple of awning fabricators and
ask them their thoughts.

Resin is added to sailcloth to stiffen it for better sail shape and to
make the fabric non-porous so the wind doesn't blow through it.

Good luck.

Re: Grommets as drain holes in canvas awning?
On Sat, 27 Dec 2008 09:23:42 -0800 (PST), snipped-for-privacy@aol.com wrote:

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It seems to me that for drain holes, the kind of eyelets used on
18th-century corsets would work fine:  Punch a hole with an awl,
trying not to break any threads, just push them aside.  (Some *will*
break, but minimize it.  It helps to start with a blunt needle, then
enlarge the hole with an awl.)  

Overcast around the hole to keep it from closing up again.   Some
re-enactors report that they use only twelve stitches to hold the
eyelet open.   Do not buttonhole the eyelet; that's fine for
ornamental eyelets, but the purls of buttonholing wear away on laces.
And, in this case, would inhibit the flow of water.  

(Above not from my own experience; such lacing as I've done is done
only once, so I just pull the laces through with a big needle.)

I imagine that it would be important to choose a weather-resistant
thread.   I've heard that hemp fiber is weather-resistant, and it
would have the advantage of wicking water through the hole.

Joy Beeson
--
joy beeson at comcast dot net
http://roughsewing.home.comcast.net/ -- sewing
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Re: Grommets as drain holes in canvas awning?
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Marine canvas supply houses and awning fabricators have sunlight
resistent thread, usually in many colors.  That is sunlight resistent,
NOT sunlight proof.  The thread generally lasts a few years in mid
latitude climates, much less in the tropics.  In a water draining
application, the thread could be pretty far gone and still work.  Gore-
Tex thread, now called Tenara, is guaranteed to last as long as the
canvas, but it is EXPENSIVE.  Profilen thread is a competitor, and
available on smaller cones.  Profilen is available (white or smoke
color) as "hembobs" (pre-wound bobbins, just the thread no spool
needed) for about $6.50 for 44 yards.  Profilen hembobs are not likely
to be available in any local canvas supply house.  Tenara and Profilen
are more difficult to machine sew with because of inconsistent tension
issues.

*Some* dental floss is PTFE (what Tenara and Profilen are made of),
but I can't remember which brands.  People have be known to use dental
floss in a pinch.

I'd stay away from hemp fiber (or fibre, to our cousins) as the stuff
doesn't last, sun or otherwise.

Re: Grommets as drain holes in canvas awning?
wrote:

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If you don't want someone, who is already annoyed at you, to take
something the wrong way, just say "Thanks" and don't use his idea.
Saying thanks won't stop others from giving their suggestions.

If you think maybe the idea could be made to work, just say, "That's a
good idea, but I don't always open it the same distance..."

What you shouldn't do is start out "I am not going to go out..."
Everyone knows the tone of voice that accompanies those words.  It
means, "What a stupid idea. I'm not going to do something stupid to
make your stupid idea work."  

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Who cares?

Re: Grommets as drain holes in canvas awning?
Bob F wrote:
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That would be true if the awning didn't sag under the water, which is
what usually happens.  Also, it usually sags in the middle, not at the
sides, and putting drain holes in the middle defeats much of the purpose
of the awning.  When I had fabric covered gazebos in my yard, I often
had to go out and use a broom to push up the fabric so that the water
(which is very heavy!) would run off the ends.  I was ultimately
defeated by four feet of snow, which collapsed both gazebo roofs and
bent the metal structures.   My new gazebo is cedar.
--
Joanne
stitches @ singerlady.reno.nv.us.earth.milky-way.com
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Re: Grommets as drain holes in canvas awning?
I've seen grommets used in canvas for that very reason.  I've never
seen them used in awnings, but why not?  Cheap brass grommets from a
hardware or home supply store work.  if you want nickel plated
grommets, you can get them at a marine canvas supply house, such as
sailrite.com, but nickel plated grommets are "star" grommets (star
grommets also come in brass), which are much stronger AND require
special (and expensive) dies to set them.  In an awning you won't need
the extra strength.  I'd go with the hardware store grommets.

Re: Grommets as drain holes in canvas awning?
Addition, yes you will have to take the awning down to set the
grommets.  A somewhat heavy die is set on a hard surface (say
concrete), the grommet is placed one piece each side of the canvas, a
somewhat heavy punch is set on the topside, and hammered home.  Done.

A special hand operated tool is available to set grommets, but it goes
about $140, plus about $40 for the die (each size grommet, star or
plain), plus (if you want it) about $44 for the hole cutter (each size
hole).  For just 3 or 4 grommets you can cut the holes with an Exacto
knife.  By comparison, a die set/hole cutter/bunch of (cheap) grommets
(of whatever size) goes about $15 at a hardware store.

Re: Grommets as drain holes in canvas awning?
Unless you plan to use stainless steel or any other type of non rusting
metal, the grommets will rust and eventually eat away at the canvas. Also
keep in mind, even if they don't rust, you risk the fraying of the canvas
around the grommets since they are not sewn within the grommet area. Within
time, the canvas will start to deteriorate under the weight of the water.

A solution is to simply remember to retract the awning when weather looks
bad or when you plan to be away from home. I wouldn't mess with the
integrity of the canvas.



Re: Grommets as drain holes in canvas awning?
wrote:

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I was planning on calling a canvas shop and a marine store after the
holidays. We have both in this area. I'd go with whatever they
recommend.

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Well, that *IS* the plan, but my memory being what it is...

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So I guess you would be against my second idea, which is to punch
several small holes or slits in the canvas and skip the grommets. I
wonder if I can "spread" the fabric with an awl and make a hole large
enough for a slow drain. I don't think it will take much. They might
tend to clog with debris, so I might have to reopen them from time to
time.

Re: Grommets as drain holes in canvas awning?
Square Peg wrote:
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Hi,
I used to make one end of awning little lower to make the water to run
off. Don't keep it level(horizontal).

Re: Grommets as drain holes in canvas awning?
Square Peg wrote:
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Hi, Ever operated a RV or camping trailer? I used to have that big wning
on my fifth wheel trailer. I I pull the awniing it is a common sense
rule to make one end lower so water can run off canvas.
Little off topic, you don't build a deck perfectly level for obvious
reason. You never pour a drive way perfectly level for your garage.

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