Couple of turf questions

[brattenj]

I'm building a new sim room on my house and it will be 15'W X 21'L X 10'H
I'm getting my turf to cover the entire room from ProPuttsystems.com

Here is my issue: I want to use some Elite Mats that are 3' L X 20" W to hit off of. I'm a big guy and need firmness under my feet but the turf is not as high as the Elite Feel Mats. How do I build up the area around the mat?

Thanks

[mthunt]

I did the same thing and used 18"x18" basement floor underlayment tiles they sell at Home Depot. Putting green + tiles= mat