Introduction: Weaving a Pergola Cover for Shade and Warmth
I made a replacement cover for my existing metal kit shade house to replace the plastic cover that had rotted away. Since I'm a weaver of rag rugs and a scrounger in general, it was an easy choice to weave my new cover. I had previously purchased some mill ends and while the fabric turned out to be too heavy for making rugs, it was strong enough to use as a cover out in the elements while still being easy to sew.
The shade benefits should be obvious, although depending on the angle of the sun, you may need to sit outside your structure in order to find the shade! We live in the high desert with warm, sunny days and cool nights. We often eat in our shade house. For BBQing and early evening meals, we'll build a fire in our chimera that we place in one corner of our shade house. That provides ample warmth and the cover helps retain quite a bit of the heat, but the cover is still woven loosely enough so that smoke escapes easily.
If you don't have such a structure in need of a new cover, there are quite a few Instructables here that can help in that regard. And if my shorthand description of the weaving confuses you, check out How to Weave on a Frame Loom by @ChrysN for good photos on the over/under warp/weft directions.
Comments, corrections, and suggestions much appreciated.
Step 1: Material Gathering
For this 'ible, I'm going to describe how to weave a cloth top for a simple square or rectangular structure made out of square tubing. You typically find these structures sold as a kit in the big box stores in the US and Canada. Often the cloth or plastic used in these structures rots away in a few years necessitating replacement.
A square or rectangular structure will be easier to weave a cover onto. I'll address covering other shapes in the end notes in Step 6.
In addition to your structure, you'll need:
Appropriate material, pre-washed if you are concerned about shrinkage.
Sewing machine or lots of patience if you are a hand sewer.
Tools for partially dismantling your existing structure.
Step 2: Material Prep
Remove the old cover, clean and repair your structure as needed. Test remove screws or other fasteners and determine that it is actually possible to remove the top crossbars. If not, some alternate weaving attachment methods will be discussed in the Step Six.
My cloth was obtained from remnants, presumably from upholstery rolls. The width of one roll I found was approximately 4 inches wide and I used this material (the brown shade) for my warp. The other material I found (the blue shade) was about 12 inches wide. I rolled this material up tightly into a roll, and cut it into four-inch strips with a sharp knife. A serger would be ideal for this process since you could cut and seam the edge at the same time.
Not having a serger and knowing that conditions in my climate will make this at best a temporary covering, I chose not to hem my ragged edges. If I'm lucky, I'll get two years from this material but it won't surprise me too much if the top falls apart in a year.
I measured and put down some painter's tape on my floor and used that for measuring the length of material needed. My structure is made from mild steel tube. The corners are the structural elements, approximately 1" square and the crossbars along the top are ~3/4" and fit inside the corner tubes and are then screwed in. To make my top, I chose to sew loops in my material and then unscrew the crossbars, insert the loops, and reattach.
Step 3: Cut and Sew Your Loops
My structure is approximately 9' by 12'. So, for my warp (brown) fabric, I test fit a piece of the cloth around a bar I had lying around and marked it with a marker. Use the actual bar on your structure to test fit if need be.
In my case, I went with 3 inches on each end to leave plenty of room to slide the cloth around the bars. I made my warp strips 12 feet, six inches long, pinned each end three inches in and sewed the loops using a zig zag stitch. For the weft (blue) fabric, my lengths were 9 feet, six inches before sewing.
The idea is to make the warp and weft strips close to the length of your bars but not so tight that you have to work very hard to force the loops over the bars. Some slack will also be taken up as you weave the strips in. A test fit of one strip is a good idea before cutting and sewing all your strips.
Step 4: Loop Your Strips Onto the Crossbars
Once you have all your strips prepped, take your warp (brown) strips out to your structure. Remove one crossbar and slip all your strips on. You may be able to just remove one end of your crossbar to do this, just be careful that the bar doesn't bend and break from the weight of the cloth. I found it easier just to remove the bar. It's a good idea to mark the left/right ends of the bar so that the screw holes will match when you reinstall the crossbars.
For variety, I chose to flip alternating strips of the warp strips. If your fabric is amenable to this, you may want to plan this initially and plan to sew your loops appropriately. I tried to sew the “flap” end of my strips so that they would be on the top and not visible when sitting underneath the cover. But you can always cut off the excess.
Once one entire row of warp strips (21 in my case) has been slipped onto a crossbar, reattach the now threaded crossbar to your structure.
Loosen one end or remove the opposite crossbar, and slip the loose ends of your loops onto the other crossbar. I chose to keep all the strips in the same plane - not twisted in other words Once your loose ends are on the opposite crossbar, reattach it to your structure. It's nice to have a helper for this part.
You can quit now if you don't have enough material or if you really like the look. For more warmth, shade and perhaps a bit more snow or rain protection, continue with weaving your other strips, aka the weft.
As before, loosen or remove one empty crossbar from your structure. Place all your (weft) strips along this rod, again paying attention to keeping the strips "flat", unless you want them twisted. I did not alternate or flip my rows of weft strips. Reinstall the threaded crossbar once you've placed all your strips of weft along the bar. At this point you will have your warp strung all the way across and a bunch of "threaded" weft ends piled up waiting to be woven.
Step 5: Now the Fun Part - Weaving Your Strips.
Take a loose weft strip at one end of your now threaded crossbar and interlace it across the warp strips. Over and under, over and under. When you get to the far side near your empty crossbar, let the weft strip hang loose. You can attach the weft end to a warp strip with a binder clip if need be, but I didn't bother.
Continue with each weft strip (17 total in my case), remembering to alternate the weft strips over and under the warp strips. In other words, weft strip one will go over/under all the warp strips, while weft strip two will go under/over each warp strip. Strip three will go over/under, etc. Continue until all the strips are woven across your span and awaiting attaching onto the opposite crossbar.
For strip management purposes, you may find it easier to go partway across with each weft strip at first and manipulate the weft and warp strips to make it easier to weave. I did this to tighten the weave as I went but I still had to go back over each strip to flatten them and adjust the spacing.
I folded each weft strip up before threading them through the warp strips. This made it easier to keep the orientation the same (and yet I still had to rethread two weft strips when I put unintentional twists in them).
Now loop all your loose weft ends around the opposite crossbar that you have either loosened or removed.
Before attempting to secure the last crossbar, check your strips to make sure that none are unintentionally flipped or otherwise miswoven.
Now get a helper (or some clamps), and fit the last crossbar back into your structure. My crossbars slid into the corner post bars and attached with screws and I had to manipulate the corners about 4 to 6 inches apart to slide the crossbars in.
You may have to loosen or remove some of the attachment points of other crossbars across the top or elsewhere in order to provide enough slack to reattach the crossbar.
Depending on the length of your strips and how many weft/warp strips you use, your cover may be relatively taut or a bit saggy. See Step Six for sag ideas. However, if your material shrinks a lot, it may become too taut and some material or seams may tear, so keep that in mind when you make your measurements.
Step 6: Alternatives and Alterations
The fun thing about weaving is that there are no rules.
When you scrounge for material, I recommend getting some heavy weight cloth for longevity. Bonus points if you can score some "shade" cloth that will hold up to the elements better. You can use all the same material for your cover strips, but I chose to use contrasting shades for the warp and weft.
An alternative method for attaching your cover would be to find some square tube or pipe that can be attached with screws or clips to your existing structure. This may be your only alternative if you have a wooden pergola with heavy beams. PVC pipe may also suffice.
Note that even if you have existing crossbeams or slats overhead, this alternate attachment method would enable you to hang a woven cover beneath the cover for looks or for additional shade or warmth.
If you decide to use tube or pipe and then attach the tubing to your structure, I think I'd lay out the pipe on a suitable flat surface and weave the warp and weft strips first. You can use spring clips or rubber bands on the ends of the tubing to help prevent the strips from slipping off the tubing or pipe as you manipulate them until you can attach the tubing to your structure. I would start with the longest sides (the tubing with the warp strips) first and then attach the weft strips. For a square structure, the warp/weft would be interchangeable.
Another method for attaching strips to an existing wooden structure would be to fold and sew a Vee into each end of your fabric strip and attach the strips with a screw and a large washer through the Vee to hold the fabric in place. I think this technique would be especially handy if you have a wooden structure that's in an unusual shape, like a triangle or polygon. Again, I think I would attach the warp strips first and then weave and attach the weft strips.
You could also make a square or rectangular out of tubing, place your strips on the tubing, and hang the entire structure from your existing pergola, or just between some trees. If you go this route, anything thinner than, say, 3" PVC is probably not stiff enough to hold your strips taut.
Maybe you've figured out by now that we've turned your structure into a giant loom. :-)
Instead of sewing, there may be other ways to make your loops, but it's hard to beat thread for strength.
I'm a weaver so I'm biased toward cloth. There may be some other material out there that would make a cool cover, perhaps some thin strips of flashing (sharp edges!) or especially thin lath (maybe steam the lath strips?) With a plastic welder you could make a fun cover with strips cut from tarps.
If you want your cloth to last more than a year or two, you could try treating it initially with something like Scotchgard or spray it periodically with 303 Protectant. Or better yet, get a fast-growing vine suitable for your climate zone and hope it covers the top of your pergola before the fabric rots away.
In Step 4 I mentioned that I laid all my strips on the same "flat" orientation. I think that gives me maximum coverage but you may want to make your top airier or different by twisting some or all of your strips. If you do think you will twist some warps/wefts, allow a squoosh more length during your measuring so that the loops will fit your spans, since twists will marginally shorten the length.
Strips weren't easily attached to my corners so I've chosen to leave those bare. This is where one of the alternate attachment ideas could come in handy if you want a completely solid top on a similar structure.
Potential sagging was also mentioned in the previous step.
One method to eliminate sag would be to put a table in your structure that has a hole in the middle for inserting an umbrella. Instead of an umbrella, insert an appropriate stick in the base of the table and nail a pie tin or similar to the top to spread the weight of the cover onto the stick a bit. You could also string a line to the center of the cover strips from a handy tree and make a bit of a peak in the cover.
My cover wound up nicely taut and doesn't have much of a sag, so I haven't experimented with making a peak yet. Plus I think mine retains heat a bit better being a bit flatter and lower to my chairs.