When two domains fully open into eachother and what happens if walls and partitions fall on Shabbat

More on waste water and then carrying across roofs on Shabbat

How to dispose of waste water on Shabbat

How to draw water from a water source running through a single domain and how to draw water from a canal onto a balcony

What happens if a member of the courtyard leaves town without joining the eruv or abandoning rights? And how to draw water from a cistern that is split across two courtyards that did not join in an eruv

An eruv in a courtyard with a two level building which has a gallery, and which structures qualify as a residence to place the eruv?

How to set up eruvei techumin and how much food required (recorded on train!)

What food can be used to set up an eruv and purchasing shares in an eruv in advance

The minimum amount of food required for shitufei mevo'ot

Setting up Shitufei Mevo'ot