Our flat roof for a 300square feet room (new addition) was installed using shingles. After a year, it leaked. The same constructor came back and put a layer tar over the shingles and some roof fans, telling us that would fix the problem and charged us $1500. Another year passed, and we had another leak. Long story short, we are getting estimates from other roofers. One recommended doing flintlastic, and another recommended fiber tite. Which one is the better material? Both are around the same price. The fibertite roofer told us that the tar is going to eat away our shingles, is that true? We don’t know anything about roofing, so hope you all could help me. Thank you all!