How to sew SLITS (Vents) : 7 different methods

Slits or Vents are openings in fabric ; they are clean-finished using techniques such as facings, bindings, hems, or overlapping vent constructions. Slits can be added to necklines, sleeve hems, side seams, skirt backs, and the lower edges of tops and dresses.

Sewing tutorial for Vents/slits.

Checkout this video where I demonstrate how to sew a small vent on a hem; You can also find videos to sew slits with french seams on the inside, because finishing the fabric edges inside is as important as neatening your slit edges :

Different ways to sew the slit

Select the type of slit you will be sewing from this list

1.Finish the slits with a facing

This method is used when you have a plain area where you want to make a slit and you want the slit to look seamless, neat and clean.

To finish this type of slit you will be using a facing fabric piece.

Here is how to sew this slit

Step 1

Mark the slit length on the top of the fabric

Decide on the length of the slit you want – mark this on the fabric with chalk

I am going to have a slit that is 3 inches long.

Step 2

Cut out the facing 

For this take a fabric that is about 1 1/2 inches longer than the slit and about 4 inches wide. Here my facing piece will be 4 inches long and 3 1/2 inches wide

Finish the edges of the facing. Simply turn under the edges 1/4 inches and stitch in place

Step 3

Mark the slit on the facing 

Step 4

Keep the facing and fabric right sides together, the marks for the slit matching exactly

Pin in place

Step 5

Sew facing to fabric along the slit mark

Start sewing 1/4 inches away from your mark from down and when you reach the top, make this gap 1/8 and then when you reach the tip, stop. Stop the machine.

Pivot the needle and turn the handwheel once so that you make one stitch horizontally.

Pivot again and sew along the slit mark as you did earlier, ending with a 1/4 inch allowance.

Step 6

Cut through the slit mark

Do not cut through the stitches.

Step 7.

Turn the facing to the inside

Press in place.

Step 8.

Press in place. If you want a secure opening you can top stitch along the slit opening. As for edges of the fabric, do the stitches by hand  

2. Finish the slits with binding

Mark the slit on your fabric. Cut out 1-inch wide bias tape long enough for binding the whole slit.

Now you have to bind the edge of your slit with a bias-cut fabric strip.

When you reach the top point Open up the whole slit till it is a straight line.

To sew the binding, keep the bias tape right sides down on the right side up fabric piece slit edge. Sew with a 1/4 inch seam allowance.

After this turn the other edge of the bias strip to the back and fold 1/4 inch inside. Pin in place.

You can now stitch from the top along the fabric edge (stitch in the ditch basically) catching the back folded edge.

Now when the binding is complete, fold the area right sides inside and together, like this.

Sew a diagonal stitch as in the picture below.That is it.

On the front it will look like this.

3.Finish slits as you do regularly

Sew your side seams with 1/2 inch seam allowance.

Sew till the mark for the vent. Back stitch and anchor the stitch.

Now press the seam allowance open.

When this is done, fold the seam allowance at the vent sides twice (1/4″ -1/4″) and stitch in place.

The mark will form a line 1/4 inch under the point where the hem edge and the side slit edge meet (on the stitching line, not at the edge). Cut the extra outside of this line. Do this for both sides.

Fold the edge so that the side edges meet as in the picture below.

Sew through the line you have made earlier. 

Now when you bring it right side out you have a neat mitered corner.

Use a knitting needle or something sharp to bring the corners to point properly. Hand stitch or machine stitch the sides and hem.

5.Finish french seamed slits 

Mark the slit top end on your fabric with a horizontal line. Mark the slit seam allowance 1/2 inch.

Keep the two fabric pieces WRONG SIDES together. ie the rightsides will be to the outside for both the pieces unlike for the normal seam.

Sew the seam of your two fabrics with french seams till 1/4 inch above the slit line. Curve stitch to the inside to meet the slit mark. (I have not stitched like that in the picture – you can leave it unstitched also). 

Cut open the slit top edge as in the picture above. I have also trimmed the seam allowance above the slit line to 1/8 inch.

Now finish the french seam by turning the seam and sewing the fabrics 1/4 inch to the inside.

The french seam and the slit edges are neatly separate. You can use a fray check on the fabric edges of the cut if your fabric frays.

Finish the edges of the side slit as usual- turning to the inside and sewing. 

6.Finish slits with piping

This is another excellent option.

You can keep the piping tape along the seam line and bring to the back and stitch in place.

Check out this post on sewing piping here for detailed tutorial.

7.Finish slits with overlapping

This refers to the kind of finish given to openings on the back of a pencil skirt.

You can check out the post on sewing Kick pleats or  sewing a pencil skirt to learn how to sew this.

After sewing the slit, you may come to a point when the slit seam starts to unravel – this is a common issue with slits – as an opening, it stretches and the cotton threads holding the seam together either pops or becomes loosened. You can add a bartack stitch at the stress point or an arrowhead stitch, as in the picture below or a more sturdy one in this arrowhead stitch tutorial – arrowhead stitch is the perfect reinforcement stitching for slits which get a lot of wear.

Some fabrics may be more prone to seam slippage than others near the slits. For eg. Loosely woven linen and sheer fabrics like chiffon may have poor seam strength near slit apexes unless stabilized or lined. Another fabric that has this problem is rayon- a lot of clothes are made in rayon nowadays and the slits have to be reinforced with stay tape or some such reinforcement.