How many shingle glue tubes are needed?

The amount of shingle glues will greatly depend on your location, and your cabins exposure to the elements.

If your cabin is mostly shaded then the self adhesive bitumen may not get a chance to mold properly, meaning a dab of glue may be required for every tile.

Or if your cabin is constantly getting battered by coastal winds we would certainly suggest heavily gluing your roof further.

On the other end of that extreme, A typical Uk sheltered garden may only require dabs along the ridge lines for additional support.

As an example though for a typical 3m x 3m cabin we would recommend two tubes of glue.