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?
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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.
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wrote:

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.
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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.

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.
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wrote:

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?

Yeah, like 5-6 feet.

Are you sure your name isn't Rube Goldberg?
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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.
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wrote:

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

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.
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"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.
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On Sat, 27 Dec 2008 09:23:42 -0800 (PST), snipped-for-privacy@aol.com wrote:

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
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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.
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On Sat, 27 Dec 2008 09:23:42 -0800 (PST), snipped-for-privacy@aol.com wrote:

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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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.
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wrote:

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."

Who cares?
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Bob F wrote:

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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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.
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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.
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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.
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wrote:

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.

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

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.
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Square Peg wrote:

Hi, I used to make one end of awning little lower to make the water to run off. Don't keep it level(horizontal).
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Square Peg wrote:

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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