This is a tutorial to show how to insert a lapped zip. I’ve just launched my third dressmaking pattern, a little girls sleeveless dress with a gathered skirt, that zips at the back. Zips are one of those things that people sometimes prefer to avoid because they seem a bit tricky. However with a little bit of know how and a few simple tricks there is no need to fear applying a zip.
A lapped zip is a neat application. The fabric of one side of the seam is folded so that it covers the zips teeth. A lapped zip is a versatile application that can be used at the back or side of dresses as well as for trousers, skirts and cushions.
Its best to use a standard dress zip with plastic teeth when applying a lapped zip. Not to be confused with invisible dress zips. A standard dress zip will have the teeth proud at the front of the zip. Where an invisible zip will have the teeth set at the back of the zip.
Application for lapped zips can vary slightly depending on the style. Side zips in dresses will be inserted mid seam, where as centre back zips will usually finish at the upper back neck open edge. In this tutorial I am going to show you how to insert a lapped zip into the centre back of a lined dress. However most of the process is the same whether you are applying with a facing or applying mid seam.
Press the seam allowance.
The key to making this a manageable job with a good result is partly the way you press the seams at the beginning of the process. In this example the dress is made to the point where the lapped zip needs to be inserted.
The seam allowance on this dress is 1.5cm. With the dress turned inside out press the left hand seam (left hand side as you look at the dress) approximately 1.2cm in. Press the right hand side 1.8cm. This doesn’t have to be exact, basically one side needs to be a little under the seam allowance and the other a little over. However the turnings do need to be as even as possible. The more accurate you can be the easier the following stages will be.
The narrower side helps the zip sit back a little and allows you the extra tiny (but just enough) bit to be added to the other side of the seam allowance for covering the zip teeth on the opposite side and giving you extra confidence that you will catch the seam. Hopefully if this sounds confusing it will make more sense by the end of the post.
Attach the appropriate machine foot.
Prepare your sewing machine by attaching the zip foot attachment. There are two different types your machine might have. The foot on the left has a slider so that you can move the foot across to the left or right depending on which side of the zip you are sewing. These often come with older machines. The up side of this foot is you can control how close you get to the zip teeth, (however this is more relevant when applying an invisible zip). The downside is you can hit the foot with the needle if you have set it a bit to close to the needle. The foot on the right clips on or off to the left or the right at a predetermined distance from the needle, avoiding any accidental needle breakage.
The purpose of both is to allow you to sew close to the zip teeth. If you were to try and sew a zip in with a standard foot you would not be able to get close enough to the zip teeth.
Pin the first side of the zip.
Turn the dress to the right side. Matching the pressed edge on the right hand side (narrower side) to the zip teeth. This should be butted up to the teeth, not set back exposing any zip tape and not overlapping the teeth even a tiny bit. Pin in place. If your zip is longer than the opening don’t worry, just let it extend beyond the neck edge. Make sure the end of the zip is lined up with the end of the opening.
Stitch the first side of the zip.
You might like to tack the zip in place before you start sewing. With the foot set so the needle is close to the teeth stitch from the base to the neck edge. The stitch line should be approximately 1-2mm in from the folded edge.
Prepare the other side of the zip.
Take the left hand folded edge and bring it over the zip teeth matching the folded edge to just literally 1 mm over the stitch line you have just created. This is the trickier side as you are largely working by feel. Pin the dress to the un-stitched side of the zip tape. Take care that any waist or other style lines and neck edges are matched up.
Prepare the final side of the zip.
This side is well worth tacking especially if you have a fairly long zip like a dress zip. Tack the dress to the zip tape, feeling for the teeth. I always take care to tack along the very edge of the teeth giving a good guide line to follow when stitching, you can also check all seams are lined up nicely at this point before sewing.
Stitch the lapped zip.
Change the foot to the opposite side, starting at the base of the zip, stitch across the base of the zip from the seam out and reverse a few stitches to make this strong, pivot and stitch up the zip. Take care to stitch to just about 1/2-1mm away from the tacking stitch (towards side of the dress). This will mean you avoid sewing into the teeth but remain close enough to the zip teeth. If your zip is much longer than the dress you can keep the puller at the top of the zip and stitch the whole length easily. If your zip is an exact measurement you will find it creates a difficult lump if you try and sew past the puller. To avoid this when you are a about 10cm away from the top, stop, with the needle still in the work, lift the foot and pull the zip down to the part of the zip you have already stitched, continue to sew the last few centimetres.
Check the lapped zip application.
Check the stitching is close to the teeth and that the seam is caught behind the zip tape. Press the seam allowance of the lining in along the zip edges and slip stitch along the zip insertion stitch lines.