How To Alter a Store Bought Poly-Vinyl Tarp

[Ratty]

So you want your tarp to fit your structure.
A perfect fit from end to end, top to bottom.
Grommets spaced out just enough to keep it taunt.
No sagging roof or unsightly excess flapping in the wind.
I tried to find directions online but most videos and instructables are all about nylon, polyester and natural canvas fabrics.
Burners often use these woven poly tarps on their carports and flat-topped shade structures. Let's begin....
Put up your frame and measure it. Bring a pad of paper and write down EVERY measurement you can think of. Draw pictures from the top from the side, front, back, close ups of joints all with measurements. Take pictures. It's not so funny when you have to go out at night with a flashlight to find out where the crossbar is in relation to your grommets.

Figure out the size you need and buy a tarp. Tarp sizes will drive you crazy. I needed a 13'2"X 13'8". I bought a 15'2" by 19'6" or something like that.
My plan is to cut off two sides and make it fit exactly. Let's see how that worked out.

[Ratty]

Well, first let me say tarps lie! Those measurements on the package were approximate. It is 2" longer on one long side than on the other long side. Measure the part you are keeping. Not the part you are throwing away.
I laid the tarp out and marked it for the desired size. Make a solid line to show the exact finished size. You will be adding several inches to the measurement before you cut. This is where you will fold and sew. A couple of things to consider regarding size.
Stretch? I don't think so. Not with these cheap tarps.

Attaching with bungie balls? Yes.
Picture the elastic going around the frame and through the grommet in your tarp. Your tarp is not touching the frame. It shouldn't. If it does, you will have made it a tad too big and now it flaps in the wind and sags in the middle. Bungies come in several lengths and thicknesses. 3". 6", 9" and 12". (This is the total length of the elastic so 3 and 6 inch are useless.) The elastic can correct a small error in your measurements. Ideally your tarp would fit up against your frame exactly after stretching out in the sun. I'll settle for within a couple of inches of the frame. Yes, this is my first tarp rodeo.

Use a piece of paper, (or two or three), to figure out how many inches to add before you cut. I added 4½". This way I could fold it a couple of times and sew through 3 thicknesses of tarp.

What I did was fold, fold, tape it down with some cheap removable tape. I later decided to pull that tape up and slip in some thin/cheap poly rope. I pushed it to the edge and re-taped as I went down the edge. This rope will help keep the grommets from ripping out. Fold the entire tarp accordion style so you can get at the straight seam without bunching up the fabric.

[Ratty]

Sewing... I ran 2 rows of zig-zag stitches down each new seam. It took 3 heavy duty needles to get the job done. They went through the plastic like a knife through butter. I broke 2 needles by pulling and pushing the massive project. Very easy but tedious.

[Ratty]

I think the rope in the seam was a good idea. I left it long so I can tie it to the frame if needed.

[Ratty]

What if you don't sew?

Gluing...There are several no-sew options. Glues in this day and age are a miracle. I'm not going to recommend one since I've never used one.

Clips...There are reusable and one-time-use clips on the market. With a project this size it could get expensive. I prefer the reusable ones. Search around and get them for well under a dollar each. Just fold your tarp over a line of paracord and clamp the edge. Cut off the excess. These clamps have powerful jaws and a ring to attach your bungie ball. I did this last year on one edge and it worked like a charm.

Heat sealing...This is how they originally finished your store bought tarp. It looks easy but requires some skill or experience as well as equipment.

[Ratty]

After you get it all sewed it's time for grommets. The cheap grommet set, ($4 at Harbor Freight), was useless. I was grateful to have all the grommets though. The Good set at Home Depot cost $10. It attaches 2 sizes and came with a half dozen of each size. I put them in 9 to 12 inches apart. I also added some in between the existing ones. They were at random intervals.
I took the project out the front door to the concrete stoop. A solid base made the whole thing fast and easy.

[Ratty]

So How did it work out? Pretty darn good. I like the results but next time I'll spend more money and start with a better tarp.

[Ratty]

I'm going to use the piece I cut off to make a little skirt at the bottom.

[BBadger]

What a handy guide! This could be nice for replacing those crappy carport canopies that disintegrate in the sun over time. Usually the canopies you can buy that aren't specifically made for a given carport never fit, and they're just as shitty. Now I need to get a sewing machine...

[FIGJAM]

GREAT JOB!!!

You covered ALL the bases for a home run!!!

The way you used the shark bite clips is how I helped my first neighbors, in 2010, hang their canvas movie screen to the side of their truck.

It wasn't grommeted, and the clips would slip off every time they tried to stretch the screen tight.

After watching them do this for 4 hours in the heat of the day, I had them cut a bunch of 1" pieces of 1/4" cord, then folded the edge of the canvas over the cord, and install the clips with the cord at the back of the jaws.

No more slipping, and they were good to go in 20 minutes!!!

[Ratty]

Thanks BBadger, Thanks Figjam. It isn't so special. I just took pictures as I worked.

I did forget to include the part about making your own bungee balls. Those things wear out after a few years. I never threw away the tired old stretched-out ones. I had some elastic so this year I restrung the the balls with fresh elastic. OK. Not exactly fresh. It used to be a cargo net. I untied it last year for some other project and had a ball of elastic left over. I used 16 or 18 inches of elastic for each one. It will be interesting trying to put up this tarp with all different lengths of bungies.

Also, When it came time to cut the tarp I choked on my own measurements. I was afraid that the tarp would end up too big and floppy so I amended my measurements to be an inch smaller. I really could have left it alone. Oh well. On this project 'close' is good enough.

[ZigZag]

Wow. Taking on sewing a tarp seems like such a big deal to me. I think I am intimidated by sewing for some silly reason but still, I am knocked out by how hard that seems. Amazing job, thanks for the detail.

My problem with big pieces of floppy stuff has always been that nothing ever comes out square. I made the canopy for my Monkey Hut by taping together pieces of attic foil. It should have come out square and even but didn't. The good news is that a PVC frame is wobbly enough it doesn't matter.

So my next project is I am going to make a shade for my van. I was going to do an EMT frame for it with silver tarps. I went with tarps because I don't need the efficiency of the foil but more important, I figured they'd be more likely to be square than anything I built. Given what you are writing here, now I am worried about premises of the design. Uggh.

I may have to learn how to sew.

[FIGJAM]

I noticed that some bungees come with cheap cord that gets weakened by the sun easily.

I got some cord that's UV resistant and as big around as the ball will hold.

These things have been holding up my outside shade 24/7 since last November, and show no signs of failing.

[BBadger]

It isn't so special. I just took pictures as I worked.

Yeah but a big value in such guides is the confidence boost by demonstrating exactly that it isn't "so special": that anyone can do it with some effort. Otherwise it's just "aw geez I don't know anything about how to do it; maybe I can find a friend to do it for me..."

[krly]

I admire your craftsmanship....but......wouldn't an easier way to be to just measure your store-bought tarp and then just cut the EMT to match it's size ? I'm SOOOOOO much better with a hacksaw then I am with a sewing machine !
Ken in Anaheim

[hooker]

Where did you get your steel pipe structure? I might have to give up on the PVC monkey hut and build one of those myself. They look pretty bullet proof. Is that pipe used for fencing?
JR

[Ratty]

Hooker, that structure is bullet proof. It's made by Canopy King. Just get a costco canopy/carport. They are sturdy and if you have room to haul it to the playa, well worth it.. My carport is set up 'clam shell' style. Instead of a peaked roof you just leave the legs off of one side and you have a flat roof. I think you could use those extra legs and joints to make it longer.

Clamshell style is more intimate and inviting than that tall roof.

[AntiM]

I also have King Canopy carports, and also do clamshell. Mine are from 2003.

[Ratty]

Krly, The clamshell carport has some long legs in front and the shorter roof pieces make up the back legs. This makes the roof slant. No matter what configuration you use, it's a beauty. This has a welcoming feeling. If you want to see in all directions it's one way to go. If the wind blows you can make end covers that tie on.

viewtopic.php?t=73702.

Take a look at this thread.

This will give you an idea of how a veteran burner attaches the tarps and ties it down. (I'm talking about AntiM and MyLarry of course.)

[AntiM]

We have long swathes of bedsheets we hang above inside, because our white cover doesn't totally block the UV. We also clip up some billboard vinyl or tapestries in the interior. The white bundle along the top is one of the original commercial sidewalls, we drop it in case of rain.

10519495_10203792750197862_5108247378828667823_n.jpg

[Galan]

Wow! Really impressive Ratty! Thank you for sharing! I'm also a bit phobic about using a sewing machine, but you've inspired me to consider it!
G

[superman]

Wow!! this is a really cool idea. I once ha d a DIY poll made of vinyl banners which were used for advertisement of our restaurant service. It lasted for about 3 years.


[moderator edit]

[Ratty]

The new tarp worked like a charm. No flapping noise. No torn out grommets. The pink end piece worked surprisingly well at keeping the windstorm at bay. Next year I'm putting a screen on half of the front. It can stay rolled up unless we need added shelter. If I keep this up I'll be in a box by 2019. Ooooo. Hope I'm above ground.

[BBadger]

On a similar note, after seeing your clamshell design, I used a clamshell carport-based hut this year made from a and it worked great! I didn't modify a tarp, but found a nice 12'x25' heavy duty silvered tarp that fit right over. It was about the same footprint as a monkeyhut, only slightly more spacious and made of carport parts that fit in my car. Easy to set up by one person too.

[WileE13]

Ratty

You mentioned you were able to get a grommet kit at Home Depot for $10? Is it for a single size? If so, what size? Do they come in multiple sizes?

I bought 6ft x 50 yards of white canvas, a couple hundred aluminum 1/4 in grommets and a grommet tool from mytarp.com. The tool alone was like 25 dollars and it only fits the one size. At that rate, it would cost hundreds to get all the different grommet sizes.

[Ratty]

It fit 2 of the larger sizes and came in a handy case. However there were only 6 or 8 grommets of each size. You would think they would sell grommets, but no. Check out the grommet machines. I had the pleasure to use one. It was magic.

[Ratty]

Bumping this for people that need to see how easy it is to do it yourself.

[Ratty]

On a side note...harbor freight sells BIG plastic clamps that go around the polls of a carport. $2 a piece. You can clamp anything at a moments notice. My structure has polls larger than the costco version and they fit perfectly.

[Ratty]

Bumping this for some folks from FB that need to start playa prepping.

[FIGJAM]

HF also has bag-o-grommets.