IF it is a real problem, then yes, fix it.I would build a fir-in wall out of 2x2s and insulate it heavily (Rockwool comes to mind https://www.rockwool.com/north-america/) There is also drywall that is made for this.

Now I am brand new to real estate so this could be dumb but I'm reading Brandon Turners "Rental Property Investing" book and I was intrigued by chapter 3 where he list out 4 plans to start with when getting into real estate.

They have a brand they're trying to keep consistent over the entire portfolio.

I'd do what you can to keep yourself uninvolved with it....but still help your Grandma of course..A trip to the City (Planning/Zoning/Building Depts) will give you some valuable info.

Then, start building your connection with local agents, contractors and property managers.2. 

My goal is to build a successful flipping business while keeping family time a top priority.

If you're open to exploring new markets, this could be a great way to pick up properties for cheap and build cash flow with a much smaller upfront investment.

You're better off focusing on specific markets, specific neighborhoods, analyzing numbers, and building an ideal buy [box].

Go to BUILD YOUR TEAM at the top of the screen and look for local investors or meetups in your area.

Are the new builds for owner/occupants or build to rent?