How do roofs really get on houses now that we know that they can't actually fly?

They climb up the walls, duh.

Roofs are actually grown in place and then the house is built underneath it. That’s why they have to use farmland to build houses.

Roofs actually have about 15 tiny trained millipedes strapped to the bottom of them. The millipedes crawl up the walls of the house carrying the roof along with them. After the roof is in place the millipedes are rounded up by the builders and executed via firing squad, as the millipedes had a taste of freedom while carrying the roof and can no longer be trusted to perform their duties. Although there are a growing number of builders that prefer to send the millipedes to a farm where they can roam freely and live out the rest of their short lives in peace.

If real life is accurate to games that let you build bases, you just climb to the top of the walls and hammer one single corner until the progress bar fills and the roof appears.

jump good

Reverse tornadoes, harvested from the other side of the equator where they spin backwards.

Ladders

A miracle performed by Jesus.