Posted on 04/16/2019 1:06:00 PM PDT by Diana in Wisconsin
Firefighters stood helpless to stem the blaze Monday at Notre Dame Cathedral, likely because of Gothic engineering techniques that waterproofed the roof, consigning it to destruction.
The roof and spire of Notre Dame were all but doomed to burn once flames began to spread, possibly begun by a renovation accident, according to Ted Henderson, who studied archaeology at Dartmouth College. Henderson said a Gothic engineering technique used to waterproof the top of the cathedral involved placing a lead sheet roof over a wooden truss structure on top of the groin vault that served as the ceiling of the cathedral’s nave.
The wooden truss became highly flammable as it dried over hundreds of years, but was completely sealed from the outside by the lead sheets, and therefore impervious to firefighters’ efforts to douse the flames with water, Henderson said.
“So the wood catches on fire and it’s not actually exposed to the outside of the building anywhere,” Henderson told The Daily Caller News Foundation.
“In fact, the reason the roof is covered with lead is so water can’t get inside. It’s specifically fireproofed. So when the firemen, you know, arrive on the scene and they’re spraying [the] cathedral with water, it’s running off the sides of the lead roof and can’t access this void where the fire is actually spreading.”
As the fire grows hotter, the lead super-heats and melts, falling down onto the stone vault of the nave, which overloads the vault and causes it to collapse inward, creating an imbalance of weight throughout the entire structure and possibly leading to a total collapse, Henderson said.
A number of Gothic cathedrals have suffered near total collapses due to fire throughout history, including the Papal Basilica of St. Paul Outside the Walls, which burned in 1823 because a workman repairing the lead roof accidentally began a fire.
Notre Dame, however, has partially survived. The spire collapsed but the bell towers are visibly intact. The organ has survived, as well as the treasures, such as the crown of thorns relic, officials say.
The crown of thorns was kept in Constantinople during the Byzantium empire until Emperor Baldwin II offered it to King Louis IX of France in exchange for hefty financial support of his nearly bankrupt empire. The crown of thorns was considered at the time to be “the most valuable single object in the face of the earth,” according to Henderson.
The crown of thorns has been in near continuous royal possession since Constantine the Great, with the exception of the time between when it was stolen during the French Revolution and when it was returned.
Primarily because the attic and spire didn't have a sprinkler system.
If the lead sheeting was keeping the water from the Flames, why were so many of the flames shooting up through the roof?
I am quite surprised that no sprinkler system was ever put in place.
I bet the new one will have one.....................
No drone mini firetrucks?
Totally moot argument. The original construction including the lead cover was not amenable to sprinkler installation, physically or economically. As the article states, the reason that efforts to put out the fire failed is the obsolete lead sheeting.
logical assumptions, but I won’t be truly satisfied till an independent outside group of fire experts find the source and how it spread to the entire structure. Rebuilding is not a major concern, it’s only money and God knows the religious community will supply more than enough( well, we know who is still dancing in the streets, so don’t expect anything from the majority of Muslims} Wondering how safe is Mecca?
After the lead melted in some places.
From articles I have read today, once the fire became intense enough, the lead melted and revealed the flames underneath. The lead roof was to protect from burning embers being blown from a local fire outside the cathedral, not inside.
Is there a King of France today?
The lead melted, crashed inward and let the flames thru. It’s in the article.
Not this crap again. Conspiracy theorists did it with the twin towers, and now they will do it for this.
Fire is hot, things get hot, and things melt. Good grief!
I’m still waiting to hear what ‘Structural Engineer’ Rosie O’Donnell has to say before I make my final decision. ;)
*SNORT*
Exactly right. Simply because they didn't want to put out the fire.
Islam dedicated the area around Notre Dame as Nakba place(Yasser Arafat created term) means: 'It remains bitter and continues to burn'
Authorities know Notre Dame couldn't be saved.
The Pyramids are the next major monument that will fall. We're witnessing a new Islamic Crusade with most peoples eyes shut.
>> If the lead sheeting was keeping the water from the Flames, why were so many of the flames shooting up through the roof? <<
Because eventually, lead burns. Remember the bright yellow smoke? That’s lead on fire, burning as if it were plywood.
A sprinkler system would have sprayed the support structure, cat walk and the bottom of the roof decking. Water would get through gaps in the decking and mitigate any fire between the top of the decking and overlaying lead sheathing.
Where would they use hempcrete?
Thanks.
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