I am currently renovating a very old wooden chalet (80 ± years). It is raised approx 30 cm off the ground and has a tongue and groove floor, all the timber is sound. I'm wanting to insulate under the flooring but I don't want to ruin the t&g. I'd thought of putting a load of old loft insulation into bin bags and pushing them in from underneath. I've looked online but can't find any information, so I'm guessing it might be a non starter. Any suggestions would be welcome.