The Wembley Arena started life as the Empire Pool building on the site of an ornamental lake that was a feature of the British Empire Exhibition of 1924. It was located across from the entrance to the original Wembley Stadium, a building for which Owen Williams was the engineer.  As its name implies, the Empire Pool was home to an Olympic sized swimming pool that was used in 1934 for the Empire Games, the predecessor of the Commonwealth Games.  The "Engineering Timelines" website says that, "At the centre of the building was the pool, 60.1m long by 18.3m wide. The brief called for a flexible building that could be used for both major swimming events ... as well as other uses such as ice skating, tournaments and music events ... ."

The building was constructed entirely of concrete and it featured a single roof span of 72 meters that covered the pool and seating on either side for 4,000 spectators. 

"Engineering Times" explain that, "This is achieved in reinforced in situ concrete using three-pin portal frames in structural bays of 6.7m.  Internally, the tapering portal frames are expressed as shallow ribs. The main part of their bulk is expressed on the outside of the building, a technique that allows the structure to appear from the inside to be quite slender, especially at the top of the roof. Rooflights between the frames over the pool area provided good daylighting ...  The building's defining feature are the vertical rectangular concrete fins on the long elevations. The weight of these fins holds the portal frames in place, counterbalancing them."