I am starting my first serious DIY project - converting our garage into a playroom for the kids. The garage floor is concrete.
My plan is to run timber (Sawn Kiln Dried Timber (L)3000 x (W)75 x (T)47mm - B&Q) joists across the concrete floor. Then put down an MDF floor, put down carpet mat and carpet. I am going to fill the gaps between the joists with floor insulation (Jablite Flooring Polyboard).
I don't want the floor to sag between joists, but I don't want to go overkill with the number of joists.
What factors should I take into account when working out how many joists to put down? In other words how much of a gap should I leave between joists?