Construction

The
Construction

After its original plan the wall started in Newcastle (Pons Aelius). The boundary was heading west along the northern side of the river Tyne crossing it near the fort at Chesters. Now the wall runs through the Whin Sill a rough terrain consisting of volcanic outcrop. Today this stretch of the curtain is the most impressive part. Further west the the landscape becomes more gentle, the course of the wall and the Stanegate are just divided by the river Irthing. The Willowfordbridge provides the crossing right next to the fort at Birdoswald. West of Carlisle the stonewall follows the Solway Firth till it hits the ocean at Bowness-on-Solway. The length of the whole construction was intended to be 76 Roman miles (113 km), but after a change in plan it was extended in both directions. On Hadrian's Wall we are able to identify the builders. The three Britain legions the legio II augusta, the legio XX Valeria Victrix and the legio VI Victrix can be identified by building inscriptions. The legions built clearly the main parts of the whole curtain, although there are hints suggesting support of auxiliaries and even of the classis Britannica (the fleet). Each legion had a different building style that can be recognised by different milecastles and turrets (sometimes even on the wall itself). Hence the building legion can be identified at most parts of the wall even without inscriptions (naturally there are difficulties on the turf wall).


View from Hadrian's Wall	Steps of Poltross Burn	Narrow wall approaching a turret
From Newcastle to Willowfordbridge the whole construction was made of stone. The width of the curtain was intended to be 3 m (10 ft), but while the building was going on it was narrowed to 2,5 m (8 ft - sometimes only 6 ft). This gives us the information that the milecastles and turrets were built first ready to be connected by the broad wall. With the connection by the narrow curtain there are clearly visible offsets. The height of Hadrian's Wall is assumed to be between 3,5 m to 4,8 m. The steps at Poltross Burn for instance suggest an inner height (south) of 3,6 m and an outer height (north) of 4,2 m. West of Willowfordbridge Hadrian's Wall was built of turf on a length of 31 Roman miles. The reasons for this change of material remain uncertain (maybe not enough stone was available or a faster construction was needed). The height might be the same like on the stonewall, the width on the basis was about 6 m. But whatever the reason for the change was, the turf construction could certainly serve the same purposes like the stone curtain! To the north of Hadrian's Wall ran a V-shaped ditch with a drainage or a cleaning-out channel. Material of the ditch created an outer mound to the hostile territory. In average it was about 8-12 m (26-40 ft) wide, between wall and ditch existed a berm, 6 m wide on the stone wall but just 1,8 m wide along the turf construction.