My backyard is a mix of full sun and dense shade, with some in between. We recently had some construction done on the back of the house and the turf is torn up, plus the shade/sun profile has changed due to the the add-on. I have some of the established Bermuda turf now in mostly shade and need to replace it with Fescue. Other areas where there is established Fescue are thinned out because of the construction abuse. Other areas are exposed dirt.

I had a sod installer suggest something unique today. He said he recommends laying Bermuda sod everywhere (because it is much cheaper than Fescue sod), but first doing dirt work, grading, and bringing in some topsoil, then heavily seeding Fescue right before laying the Bermuda sod over it. In the shade areas, he says the Bermuda naturally will thin out and the Fescue will grow up through the Bermuda sod. The sod, he says, will help hold the seed in place and control the temperature (it can still get hot around here in September/October) so it has a better chance at germinating and putting down deep roots between now and next spring. He suggests overseeding in the spring and fall. In the mixed areas of shade and sun, both grasses may mix (as they do already anywhere where Bermuda and Fescue meet). In the sunny areas, the Fescue may survive through the fall, winter, and spring, but will not tolerate the heat here (Tulsa, OK - USDA Zone 7a), leaving only Bermuda. He says the disadvantage to laying Fescue sod in the shady areas are cost and uncertainty that it'll thrive in the weeks after being put down because temperatures may trend too high to be ideal for it.

I hadn't heard of this idea before. I know some people overseed rye or fescue on their full-sun bermuda lawns in the fall so they'll green up in the fall/winter while the bermuda goes dormant, knowing it'll die out and be taken over by the bermuda in the summer. But I've never heard of purposefully putting Bermuda sod in dense shade with Fescue seed underneath. The sod installer is very highly reviewed and has been in business for a long time locally. He is rated 4.97/5.00 stars with 62 combined reviews between Facebook and Google. If he wasn't so highly regarded, I'd have dismissed his idea immediately.

Does anyone have any experience doing this?