NO grass is "happy" in heavy shade. "Shade tolerant" grasses mean they can take more shade than some, but it does not mean they will thrive in heavy shade.
To keep grass growing in heavy shade, you need to overseed twice a year, every year, to keep up with the rate at which it fades. It can be done, but it's a constant http://www.accessiblepyrenees.com/choose-the-right-grass-seed-for-your-yard/ battle.
You might try thinking "outside the lawn", and go with groundcover that LIKE shade. Maybe put in paths, pots of colorful shade-loving http://www.accessiblepyrenees.com/choose-the-right-grass-seed-for-your-yard/ annuals, a bench or such here and there, or the shade spots into shade gardens, with plants that enjoy the shade.
To keep grass growing in heavy shade, you need to overseed twice a year, every year, to keep up with the rate at which it fades. It can be done, but it's a constant http://www.accessiblepyrenees.com/choose-the-right-grass-seed-for-your-yard/ battle.
You might try thinking "outside the lawn", and go with groundcover that LIKE shade. Maybe put in paths, pots of colorful shade-loving http://www.accessiblepyrenees.com/choose-the-right-grass-seed-for-your-yard/ annuals, a bench or such here and there, or the shade spots into shade gardens, with plants that enjoy the shade.