"This house has been being built for years" is perfectly grammatical and contrary to what @Colin Fine says, many people would normally use it. There isn't any real alternative, so if one needs to express what the sentence says, they must use this tense. Get down to reading books and the tense will not sound awkward in no time.
Compare the following:
I've been being shot at.
I've been shot at.
The second sentence doesn't really make any sense. You may say that "you've been shot", but that's totally different, naturally. There's no alternative to "I've been being shot at."
Some people obviously don't understand the meaning behind those two sentences, so I'm updating my answer to explain myself.
Past: They shot me!
Present perfect: I've been shot!
This sentence has no present perfect continuous, because it's not a continuous action!
Going on ...
Past: They were shooting at me!
Present perfect continuous: I've been being shot at!
This is the only way to express the continuous action in present perfect (continuous)!
Another example that came to my mind while my answer has been being updated ... is ... uhm ... already expressed :)
For all the native speakers who would never use this tense: learn the language better and stop using the native speaker card, it's useless...