So many grays turn blue. after much trial and error for bdrm, bath and water closet , i'm happy with Benjamin Moore Horizon and Behr ultra in Burnished Clay. Neither look great on the card but they dry to a soft neutral gray. worth getting samples to try.

I'm a Certified installer for Trex decking. Trex Transcend is encapsulated board, with a finish that resists staining, scratches, mold and has a high definition wood grain surface. I don't know what you did to it or whoever worked on your house did something to it, but Transcend decking does not need staining or painting and the protective shell protects decking against fading. Trex Transcend and a few other Trex decking products like Trex Enhance, and Trex Select, they cannot be painted or stained. The only thing can be painted is Trex Transcend White Railings and you should only use light color paint. If you use dark colors, it will absorb heat and it will damage the surface and you can kiss your railings good bye. Also high quality fast drying primer should be used and you have to use Oil or Water based exterior paint and most importantly surface prep is the the key. When it comes to painting specialty surfaces like Trex Railings, hire a Pro to do the work. With that said, if you installed Trex yourself, you have to go to the store and have a Trex representative come out and check your deck. They will determine if loss of color fading was due because of negligence or not. If its a material defect, they will cover the material cost. If you had a Certified contractor do the work, they will cover material and labor. Call your contractor and he will get a Trex Rep to come out within a few days. Good luck

Instead of the solid grey, you can go for sketches in grey with flashes of mustard/ yellow. Or, look up these links for wallpaper ideas https://goo.gl/images/OrCtY1 https://goo.gl/images/0ZpAmU

you can give some live colour to walls, can put beautiful wall paintings and some indoor plants give peace to house , beautiful designer lights , textured paint .... all of these will help to give attractive look to your corridor.