DIY tarp question

[Ejimo]

I am getting ready to attempt my first tarp. But I have a question regarding the Ridge seam. When sewing the flat felled seam.

I watched Fronkey's excellent video. And he lined the ridge ends up evenly, sewed his simple seam. And then finished off the rest of the seam.

My question is. Wouldn't one side end up longer than the other after finishing? Your folding it in one direction, so it seems to me you would be taking up more on one side than the other. Is this true?

[VictoriaGuy]

Yes, you are correct.
I don't think that 1/8" of 'offset' makes much difference, but you can always trim one side of the tarp before hemming the outside edge if it bothers you.

[Ejimo]

Thanks VictoriaGuy! I just wanted to be sure I wasn't imagining things. As long as it won't cause any issues with the offset I have no problems.

[gmcttr]

The time honored method of sewing a flat felled seam is to line both pieces up evenly, make the first stitch and then trim the hem allowance on one side to create the offset prior to folding over. Always seemed unnecessary to me on a tarp...I can live with a 1/4" "error".

[VictoriaGuy]

The time honored method of sewing a flat felled seam is to line both pieces up evenly, make the first stitch and then trim the hem allowance on one side to create the offset prior to folding over. Always seemed unnecessary to me on a tarp...I can live with a 1/4" "error".

I'm not sure, but I think the OP was referring to the fact that with the 'time honored' method, the middle of the tarp is at one edge of the FF seam. If we then attach the suspension to the 'bulk' of the FF seam then the tarp is 'unbalanced'.... Offsetting the fabric layers before sewing the first line of stitching would make the 'imbalance' even greater. With light fabrics-not denim- but tarp fabrics, I just turn both layers under before sewing the second line of stitching to make the FF - no offset, no trimming.
But, I think we are all saying the same thing in slightly different ways?

[doogie]

That is why I wait to cut my cat cuts until after the ridge line is done.

[Ejimo]

I beleive GMcttr And Victoriaguy have it correct for my question. When you watch Fronkey's video he lines them up perfectly, Sews, cuts half of one frill so that he can then fold the longer end over twice and then sew again. Which when I tried it with paper left one side about 1/4in longer than the other since your folding it toward the cut side.

So here's my thought. If for example you plan on having a 1/4in seam. Could you not line one piece 1/4 down from the others top. Sew it 1/4 in below that(essentially a 1/2in from the top of the higher piece). And then fold the top portion over and complete like fronkey showed and thus eliminating such differences in the 2 pieces? Or is my idea flawed?