You could move the house further to the south so the light can hit the grass. Or you could lower your roof line.

Would you consider putting a field of some other ground cover in where the shade hits in the winter?

I'm with David. Some things you can't fake when it comes to lawn grass. Enough sun for the variety is one of them.

That is a reality that is affecting my lawn area more and more each year as my success with shade trees around my home increases every year.

The first warm season grass that is more shade tolerant that comes to mind is one Texas Tech helped create. Its called Shadow Turf.

Past a certain point regarding sun/shade, you have to go to non-grass groundcovers. Bermuda is on the high side. It likes sun and will simply disappear in too much shade.

On the north face of my house the sun affected area is about 8 feet out from the house foundation. The first four feet are flowerbed and the rest is just whatever grew there. Mostly weeds and undesirable grasses. They are green so I have not tried to fix it yet but it doesn't look all that good with that mixture of stuff growing there.

We've done much the same as rdaystrom in our yard. We have about 80% tree coverage anyway so up against the house on the north side never sees the sun. We eventually put some shrubs and under that we have Asiatic jasmine or mulch.

Weasel on the north side you just need to plant shade loving ground covers from the foundation of your home to 4 to 10 feet away depending on the height of your home.

What I would do is give it a season or two and look for the divide line line Mother Nature will draw for you. On one side of the line will be thin grass. The other will be healthy thick grass. I think you get the picture.