For the flooring of 'Warm Thatcham' I used 2.5mm balsa. It's cheap, can be cut with a craft knife and I can easily get my hands on it. I cut into lengths 1/2" wide. For this house I wanted to really capture the idea of it being a real floor and I wanted light from above and below to filter through the cracks. I laid out a grid work of beams first. I used 9mm square balsa. I whittle the edges with a craft knife and sanded it a little. For the effect of peg type nails I used a round needle file to put a hole in the ends. Pushed in a satay stick which I cut of with bullnose pliers. Stained them and then glued in place. Beams around the interior on the first floor line and then crossbeams on those. L shaped cut out on each end so it would sit flat for the floorboards to sit on above. I laid lighting wire along grooves I cut out along the top of the beams all the way over to the chimney which is where I was hiding all my wires.
Floor boards cut into varying lengths. I made knot marks in some by going at the wood with the round needle file at an angle. Then stained them. Laid them down on the supporting beams and pierce a small hole where a peg would go. Where it would go through to the beam if it were real. Holes made with round needle file but used toothpicks this time as pegs, again cut off with bullnose pliers. Glued them in place. Occasionally checking that it was fairly straight. Allowing a little wonkiness and cracks. Worked my way across and cut the ends of when all done.
I love the effect. While it is easy to do it is the most time consuming. This was a small floor area to work on so I went a little bonkers doing it. For the Coventry I used precut timber flooring. I got them from ebay. Yay ebay!! $7 for a bag of 100. It's oak and are very thin. Easily cut with scissors. Cut a heap in varying lengths and glued them on straight to the ply floor of the house. Went along after and filled in the gaps. Cutting around corners and allowing for doorways etc. Gave it all a light sand then quickly painted on the stain. I left it darker around the edges, rubbing it off more where people would walk. I have found here in our tropical climate that after high rain and humidity the floorboards curved a little. I loved the look but I think to stop that from happening I would have to cover the entire timber strip piece in glue and work in sections. Placing something heavy on it to keep it flat and let it dry out. But I loved the curled look. I did the same for the first floor. This method is so much quicker and easier but a different look. Way to go with larger areas to cover.