VIDEOClick to see full answer. Moreover, how do you nail down floorboards?Secure the new board in place using 50mm ring-shanked nails or “cut floor brads” (nails designed to give extra hold), making sure you avoid the existing holes in the joists. Drill pilot holes in the joist first or use 50mm countersunk screws with a 4-5mm gauge to avoid splintering the wood.Furthermore, is it better to nail or screw floorboards? If you want to have access to wiring and pipework through your floor, screws again are the way to go. Another great advantage is the fact that screws will pull the boards down better than any nails and hold without popping out. Unless you use secret nailing, nails will remain a noticeable feature. Similarly, you may ask, how much does it cost to replace floorboards? The average cost to replace or repair a plywood subfloor in a 306-square-foot room costs $555, or between $490 and $600. The average cost to install a new plywood subfloor is $620, or between $572 and $720. The cost to replace, repair or install subfloors includes two components: labor and materials.Can you lay new floorboards over old floorboards?The first is that old, softwood floorboards are rarely flat, which means that the surface of your old floor mightn’t be ideal to provide a stable base for your new floor. The first, if the existing floor is not too uneven, is laying the new solid wood floor over the existing boards at a 90-degree angle.