Seeing as the wood chuck and the apple cider aren't relevant to the question of pancakes, I'll answer that solely. (I'm assuming that the amount of cider absorbed by the pancakes will be negligible to their overall weight).
The African elephant is on average
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for an area of 146.67 square feet. The White House is
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for an area of 14,364 square feet.
Assuming we can cook the pancakes in any dimension to evenly fit the roof, you get one layer of pancakes on the roof being 97.9 pancakes, which we'll round up to 98.
The average pancake weighs
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Operating under the assumption the White House roof handles an average amount of weight of
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, we find that White House Roof can handle about 14 layers of pancakes.
This means that
the White House can hold approximately 1,372 elephant sized pancakes.