What is the best way to tape a cardboard box?

While moving recently, my wife and I had a lengthy discussion on where tape should be placed on a box in order to maximize strength while using the least amount of tape possible. Assuming we already taped the main opening of the box shut, how can we make sure the box doesn't break open with weighty items inside?

To me, it doesn't make sense to put tape perpendicular across the opening of a box, detailed below.

``````(Top/bottom of a closed box)
_________________
|        |        |
|        |        |
|        |        |
| - - -  | - - -  | <- Tape across here
|        |        |
|        |        |
|________|________|
``````

This doesn't strengthen any weak points of the box. If anything, it may only be helping the tape that is going across the box's opening stay in place.

Although the surface area actually being touched by the tape is seemingly small, it seems that putting tape along the side openings of the box would directly strengthen the weakest point of the box, detailed below.

``````(Top/bottom of a closed box)

Tape along the seam here
↓ ↓ ↓ ↓ ↓ ↓
_________________
|        |        |
|        |        |
|        |        |
|        |        |
|        |        |
|        |        |
|________|________|

↑ ↑ ↑ ↑ ↑ ↑
And along the seam here
``````

What's the best way to tape a box closed to maximize the strength of the box relative to the amount of tape being used? (May not necessarily be one of the options described above.)

• Welcome to lifehacks.stackexchange. Thanx for what I think is a great question. Not only will there be some suggestions and alternatives, but it is the type of question with answers that can be tested by real life experiments. – Stan Aug 24 '16 at 21:55

How to securely seal a cardboard box with tape

Before you put anything into a cardboard box, you should tape up the bottom of the box. If you don’t, and only fold the bottom of the box flaps over each other, the box could collapse when lifted. You don’t want your best china in pieces all over the floor!

TIP: Never interlock the flaps of the box as it reduces the strength of the box.

TIP: Optional The quickest and easiest way to seal a cardboard box is to use a handheld tape dispenser which applies the tape tightly to the box and helps reduce tape waste.

To provide extra protection and ensure all the flaps of the box are sealed, use the letter “H” seal method used by most moving companies.  It is called the letter “H” method as once complete, the tape on the box will look like a capital letter “H”.

TIP: The “H” seal method will also reveal any evidence of tampering with the box because of the quantity of tape that would have to be removed.

1. Fold two of the smaller box flaps in followed by the two larger ones.
2. Seal the edges of the cardboard box going across the whole length of the box where the flap edges join.  When doing this, allow an overhang of tape.  Fold the overhang of tape to the side of the cardboard box.
3. Seal the edges of the cardboard box going across the whole length of either side of the box where the flaps were closed. When doing this allow an overhang of tape. Fold the overhang of tape to the side of the cardboard box.
4. Pack the box. Ensure the contents are adequately protected by using bubble wrap, polythene, loose fill, or air-cushion packaging.
5. Repeat steps 1, 2, and 3, above, to seal the top of the box.

Once complete, your cardboard box will be sealed on all openings and the tape will resemble the letter “H” on the top and bottom of the box. This method will provide optimal support for the box contents.

It’s always better to use extra tape and provide a double layer if you are boxing very heavy items.

• Good answer. The only way to make it any stronger than your H method would be to also glue the bottom flaps at assembly; though that will turn it into a permanent box, with no option to quickly flatten & keep for re-use. – Tetsujin Aug 25 '16 at 8:17
• Great answer, Stan. If we apply a double layer of tape for extra strength, I'm assuming we want to overlap the existing tape by about half in order to get more adhesive onto the box itself, as opposed to simply placing another layer of tape on top of the original layer. It seems the 2 layers of tape are only as strong as the first layer. Is that accurate? – arsis-dev Aug 25 '16 at 14:59
• Type of tape is also important. Using scotch tape is not nearly as strong as using real packing tape, which resists tearing better. – Mark Ripley Aug 28 '16 at 7:37