I've lived in a 10 year old new build flat and a 12 year old new build detached house in the last 3 years.
In the flat, we had no noise issues whatsoever. We were top floor, one quiet, middle aged neighbour, didn't even hear his TV. Slept like babies.
The house is a different matter entirely. If our LL sold it now, she'd probably get 600 for it. On appearances it looks to be luxury. In reality, the soundproofing is absolutely DREADFUL.
It's 2,350 square ft, so it's massive. I can hear my OH pissing on the opposite side of the house, on a different floor, with doors closed. As in, I can literally hear his wee hitting the water in the toilet. I know when he turns a tap on. I know when he has an upset tummy.
I'm regularly woken up by birds scuttling around on the roof or the top of the chimney where whatever they needed to do re: sound insulation there has been done by the cheapest possible operator.
Does upstairs and your own flat have carpets? I'm sure having none whatsoever here makes things ten times worse.
In short, I think it's down to the quality of the build, and I think our LL did things like install really, really fancy looking fireplaces and a £10,000 Aga but probably told contractors to do whatever was easiest or cheapest when it came to the fabric of the building. Things that should not be cracking, moving, degenerating (wrong word?) and breaking in a 12 yo house are. Is it normal that when you have your loft hatch open, you stand under it and wonder if there's a window open in the room? That happened today. I don't think that's normal.
Anyway, I've had enough of it today. I've given in and ordered the first two things recommended on this list, because I can't cope with the constant noise (it's on a farm, we might as well be on an industrial estate that works 20 hour days, the non stop noise is that bad).
I can't fight it anymore, all I can try to do is try to mitigate the effect it has on me and cope with it. Nobody here or anyone around me is doing anything other than just going about their daily business, but the sound disturbances in the house are insane. Even just the wind blowing makes noises inside the roof space that wakes me up.
https://www.neurodiverging.com/my-favorite-earplugs-for-autism-sound-sensitivity/
I am definitely autistic and my noise sensitivity flares up when I am stressed (which is about 80% of the time).
Day time (normal sponge ones don't work for me, even if I cut them to 1/3rd the size)
TOTAL
£15.50
Mack's Unisex's Ultra Soft Ear Plugs (50 Pair) -Beige, (1 Pack)
Day time
Vibes Acoustic Filter Ear Plugs - High Fidelity Decibel Reducing EarPlugs for Music Concerts, Festivals, Motorcycling - Hearing Protection for Tinnitu
TOTAL
£21.95