There may be some axiomatic expressions, or simple nouns that may be 99% translatable, like mother, father, flower, tree, water. I don't know. It is worth some research.
I wonder, how do you differ that 99% from 100%? Why do you believe such 'basic' nouns as mother, father, water, etc., are not 100% translatable, but 99% only? Is there anything in languages, cultures, mentality, that retains that 1%? I doubt that a Greek child, for instance, percepts a word "mother" in its language with any slightest difference, even of 1%, from an American child in its language.
This dispute seems to be as old as the languages themselves. And I stand on the opposite side with those who believe there is no such thing as "untranslatability". We are all humans and live in the same world on the same Earth, just name the things with different names in various languages. What prevents you from conveying a concept or expression in such a way that a reader in target language understands it 100% (unless it is a wordplay, of course)? If it is only 80% or 90%, I'd rather believe it's because the translation is not perfect, but not because of something is untranslatable to any extent.