For years, we have tried to figure out how dwarves can support an entire tower on one pillar of cat soap, or build a giant bridge with a few stones.
I have had some recent insights into Dwarven biology which may explain this most curious phenomenon.
We begin by observing that adamantine, also known as cotton candy, is an element from the (proposed by Earth chemists) "island of stability" beyond ununoctium. Unusually for an element of such high atomic number, it is incredibly light, sharp and- more to the point- strong, by many orders of magnitude beyond even modern carbon-fiber alloys. Dwarves need a small amount of adamantine in their diets, which is provided by trace amounts in the soil.
Normal human beards are just like our hair: they are made of a protein called keratin, which is strong, but not that strong. Dwarven beards are different: they are made of adamantin, a protein similar to keratin in which several atoms of adamantine have been added to a keratin-like structure. The result is a beard which is no less soft than a human beard- not being sharp at all- but which acquires all the strength of adamantine.
When a dwarf builds a support, they're using the support, not as a support per se, but as a connector. To this support, they tie their beard hair, which is extremely flexible and elastic, and then tie the other end to whatever the support is connecting. The result is that the support is the epicenter of an almost-invisible (and invisible to the player) web of extremely strong adamantin strands, which create a web supporting the building- even a large tower. This is the secret of not only dwarven architecture, but also the unusual properties of dwarven mechanisms.