I have been advised, that I can put salt into a trap to prevent the water from freezing in building I do not use much during tough part of the winter. I know I need to remove all water from pipes where possible, but I would like to avoid manually sucking the water from traps, especially from toilets.
can I use road salt, or is it safer to use the salt used for human consumtion? In other words - is something wrong in road salt that could damage the pipes?
what is correct dosage of road salt (for sink, toilet) if I do expect about -20 degress celsius as the lowest outdoor temperature possible (small building).