How much tulle do i get?

I just went through this as well! I rough measured and then doubled just in case. And then bought a whole boatload extra in case we have the ceremony inside due to rain so I can drake the whole room.

I would start with the height of the pergola x 2 to go to the floor of both sides. Then add in the width of it x 30% to do the draping. So:

Height(x2)+Width(x1.3)= length of fabric

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Thank you! I was thinking doubling the amount should be ok, but It's so hard to know for sure!

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This sounds like a really good formula. Thank you for sharing!!!

Also, consider that tulle is very thin, so unless it is pretty tightly gathered it is going to be almost transparent in a lot of lighting situations.... I learned that the hard way years ago when I bought a ton of it to drape on the front of dining tables for our parents' 50th anniversary party. It pretty much just blended in and didn't give me the look I was hoping for. I was super disappointed in the way it turned out. You might also look at chiffon or another lightweight fabric that has a little more substance to it.

View Quoted Comment That's a really good point. I think I will look at other materials. Thank you!!

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I would recommend chiffon or voile. They are typically more expensive than tulle, but not prohibitively. Expect chiffon to cost $3.99-9.99/yard depending on quality and weight. Voile can cost $6.99-16.99 depending on the same factors. Fabricdirect.com sells great fabrics and wholesale prices. I buy most of my fabric for decorating and sewing projects from them.

As far as length, I recommend:

The length of each side x2

+
An additional yard for 1.5' of "pooling" on either side

+

the length across the top

+

An additional 1ft. - 1 yard depending on how much drape you want.

Any excess can be cut off and used for smaller projects or simply pooled on the ground.