Square lashing is a type of lashing knot used to bind poles together. Large structures can be built with a combination of square and diagonal lashing, with square lashing generally used on load bearing members and diagonal lashing usually applied to cross bracing. If any gap exists between the poles then diagonal lashing should be used.
Square lashing steps (see image at right);
- Begin with a clove hitch on the vertical pole beneath the horizontal pole and tuck the loose end under the wrapping.
- Wrap in a square fashion about three times around the poles.
- Frap two or three times, pulling often to work the joint as tight as possible.
- Tie two half hitches around the horizontal pole
- Cinch the half hitches into a clove hitch, an additional clove hitch may be added if desired.
Strength is improved if care is taken to lay the rope wraps and fraps in parallel with a minimum of crossing.
An alternative method is known as the Japanese square lashing. The Japanese square lashing is similar to the standard square lashing in appearance, but in fact is much faster and easier to use. One drawback to consider is that it is difficult to estimate how much rope is needed, which can lead to needlessly long working ends.
- Begin by placing the middle of the rope under the bottom pole
- Lay both ends over the top pole, and cross under the bottom pole. Do this about three times. Take care to keep the wrappings as tight as possible.
- After the last wrap, cross the ropes again over the bottom pole and frap around the wrappings. Do this enough times (at least 3) to finish with a square knot.
A properly executed lashing is very strong and will last as long as the twine or rope maintains its integrity. A lashing stick can be used to safely tighten the joint.