Architectural notebook · Oriol Valls

Columns and vaults: how the nave carries itself

A stone-draughtsman explains the inclined columns, hyperboloid skylights and load paths inside the Eixample basilica.

The first thing I draw in the tree-column nave is not a capital or a saint. It is the angle where a shaft stops behaving like a classical column and starts behaving like a trunk. Thirty-six inclined supports divide the interior into a stone canopy. Their lean is deliberate: each one redirects a share of the roof load toward the foundation instead of asking an exterior flying buttress to do the work.

Look at the junctions rather than the shafts. A column changes profile as it rises, then separates into smaller branches. Those branches meet hyperboloid vaults, whose curved surfaces spread loads across several directions at once. The geometry is complex, but the structural idea is easy to read: thick at the base, divided at the crown, continuous through the vault.

The skylights are not holes punched into a flat ceiling. Their hyperboloid form stiffens the covering while admitting controlled daylight. At certain hours a bright ring appears around a vault opening and makes the load-bearing branches look lighter than they are. I recommend standing diagonally to a column; from that angle you can see how several vault cells share one structural node.

Visitors often compare the nave to a forest, and the metaphor is useful if you remember that this forest is engineered. Column spacing, height and branching are coordinated with the roof above. Nothing is decorative in isolation. Even the coloured light helps reveal depth between the nearest branch and the vault surface behind it.

For a careful twenty-minute visit, choose one bay and follow it from floor to skylight. Notice where stone joints change direction, where the inclined shaft divides, and where light enters. That single exercise explains more about the building than a rapid walk along the central aisle. The architecture is not asking you to count details; it is asking you to follow a load as it travels.

A useful drawing exercise is to mark the nearest load-bearing node with three arrows: one down the shaft and one along each branch. Then stand beneath the next bay and repeat it. You will see that the apparent forest is a series of related structural decisions rather than a collection of identical trees. The slight variations matter because they explain how the roof is divided into manageable cells. This is also why a wide photograph can be misleading: it captures the pattern but not the direction of force. A pencil and one bay are often the better tools.

A note on using these pages: the observations are written for general readers rather than as a technical conservation manual. Conditions can change with weather, restoration work and the daily life of the building. That is why I prefer describing a method of looking to promising a fixed spectacle. Stand still, compare one detail with its neighbour, and let the structure explain itself. If staff give a direction on the day, follow it. If your own experience differs from a note here, treat that as useful new evidence rather than a failure of the visit. An independent notebook should make attention easier, not turn architecture into a rigid script.