Adrian J. Boas
On the Importance of a Good Roof
Updated: Feb 16, 2020
In 2014, shortly after I moved into my apartment in downtown Jerusalem, one of the seasonal conflicts between Israel and the Hamas escalated to the degree that Jerusalem itself very briefly came under missile fire from the Gaza Strip. I live in a small, two-storey building, my apartment occupying the upper storey. Dating to the 1930s, the building contains neither bomb shelter nor a fortified room or "Mamad" which is today a standard feature in new housing in Israel. There was nowhere to hide when the siren went off, and after making a panicked sprint from room to room (fortunately I was on my own so there was no one to witness my complete loss of nerve) I ended up returning to the sitting room where I sat down and with resignation and a degree of interest observed through the widow the little puffs of white smoke that meant that the "Iron Dome" had done its job and that for the moment I was safe. My roof, which looks to be a mere 30 cm thick, would not have to prove its doubtful defensive capabilities this time.
Ninety-nine years earlier, the French General Staff reached the conclusion that in the face of the new German super howitzers, those massive 420 mm Gamma Guns, which had the ability to penetrate earth and destroy underground masonry, even the great French fortresses on the Western Front defending the city of Verdun were doomed. Indeed, in February 1916, only three days into the Battle of Verdun, the largest and highest of these fortress, Fort Douaumont, fell to a small German raiding party of only 19 officers and 79 men without firing a shot. A second great fortress, Fort Vaux fell soon after. But it was not actual damage caused by the German guns that brought about their fall. Both of them had been modernised before the war with reinforced concrete and even the shelling, the intensity of which can be clearly seen in the above photograph, did not destroyed them. All thirteen great howitzers at the Germans' disposal had been employed in this bombardment, but the superstructures were only slightly damaged, and the garrisons located deep within remained uninjured.
When Montfort Castle came under its first major attack in May 1266, there were no Big Bertha's or Fajr rockets. On the other hand, there were no "Iron Domes" and there was no reinforced concrete. Counterweight trebuchets, the latest technology in the Mamluk arsenal were used to hurl 30 to 70-kilogram limestone projectiles onto the castle roof. Everything, it seems, depended on the strength of the roof, and one might think that it would be able to do the job. The external walls undoubtedly could. Those of the main castle buildings, ranged from two to eight metres in thickness, which was certainly enough to withstand a heavy bombardment, but the roofs, it would seem, were comparatively flimsy. None of the upper storey roofs have survived today but finds from our recent season of excavations last August support the idea that their construction constituted a major flaw in the castle's design. If, as must have been known, the distances between the castle and possible artillery positions on the hill to the south, and on the extension of the castle spur to the east, would not be great enough to prevent the use of trebuchets, it seems a miscalculation indeed on the part of the castle builders that they did not ensure that the roofs could withstand heavy missile fire.
What these new finds appear to show is that much of the damage caused to the castle, which in the past was assigned mainly to the final and successful siege of 1271 and primarily to the dismantling carried out by Baybars after the castle fell, was in fact caused by missiles fired during the first, unsuccessful siege five years earlier. The discovery of stacks of large limestone sections of vault ribs from the Great Hall, which had been carried down and stored in the basement in 1266, has shown that the hall had been extremely badly damaged at that time (something we had discovered already in our first season in 2011 but now could observe even more dramatically). Most of the vaulting of the hall must have collapsed in this attack, and this could only have occurred if the storey above it had been destroyed first, so that the stone missiles together with the walls and vaults of the entire upper storey had come crashing down onto the upper floor, destroying it and collapsing the vaulting of the hall underneath it as well. In short, what we have learnt from this is firstly, that the brief siege of Montfort in 1266 about which we formerly knew little beyond that it had taken place and had been aborted, was a major destructive event in the castle's brief history, and secondly, that the damage inflicted, so extensive that it necessitated abandoning of much of the castle's upper levels, was caused because the castle's roofs were unable to withstand the missile blows.
So, it really all comes down to having a good roof. The upper storeys of Montfort were built in the Gothic method, one of the principal features of which was the employment of comparatively thin and light-weight rib-vaulting. The far more solid barrel-vaulting employed in the basement levels would certainly have done a better job of withstanding a bombardment. Indeed, they are the only examples of vaulting in the entire structure that are still standing today, although they also took quite a beating in the destruction of 1271. The considerable advantages in beauty, airiness and the use of space that Gothic architecture enabled was regarded as necessary for the ceremonial and domestic parts of the castle, even if it constituted a weakness that in this case proved disastrous.