I am having a house built by a builder. On my contract, it is specified that 'Sound Attenuating' windows would be installed.
This is important as the house backs up to a busy road which provides a lot of noise. The seller agent sold it to me as sound proof windows, but the contract only states 'Sound Attenuating'.
It is now time to order the windows, and they are being ordered as double pane, one pane standard 1/8" thick, the other 3/16" thick. From what I have read this barely provides an STC of 31 Source - Vinyl 1/8+3/16 Dual
According to Wikipedia, for STC, 30 is described as Loud speech can be understood fairly well, normal speech heard but not understood
I feel like they are filling the contract technically, but not fulfilling the spirit of what the contract was intended to do which is to protect from the road noise.
What windows or soundproofing method should be used at a MINIMUM to not hear, say, 90% of road noise?