Overlay with plywood or replace floorboards?

As long as main floor is free of movement and creeks looks solid fixed as should be totally fine any cuts in main floor will be due to plumbing or electrical works a competent tradesman should of left all uplifting of floor and relaying of good standard

When deciding whether to overlay with plywood or replace the floorboards, there are a few factors to consider. Let's go through the options: Overlay with 5.5mm plywood: Overlaying the existing chipboard floorboards with plywood is a viable option if the chipboard is in overall good condition and level. The plywood can provide a smooth and stable surface for installing the herringbone flooring. However, keep in mind that the existing cuts in the chipboard may impact the levelness of the floor, and this could affect the final result of your herringbone flooring installation. If the cuts are deep or extensive, they might cause irregularities in the finished floor. Replace the floorboards with like-for-like (chipboard): If the current chipboard floorboards are severely damaged, sagging, or uneven, it would be better to replace them with new chipboard of the same thickness (18mm). This ensures a consistent and stable base for the herringbone flooring. However, before doing so, make sure to address any underlying issues that caused the damage to the original floorboards (e.g., moisture problems, structural issues) to prevent the same problems from recurring. Consider alternative floorboard material: If you decide to replace the floorboards, you might also consider alternative materials to chipboard. For example, you could use plywood of a similar or higher thickness (e.g., 18mm) as a replacement. Plywood tends to be more durable and less susceptible to moisture damage than chipboard. Another option is using oriented strand board (OSB), which is engineered wood made from strands of wood combined with adhesive. Ultimately, the decision will depend on the condition of the current chipboard floorboards and your budget. If the chipboard is in relatively good shape with only minor cuts, overlaying with plywood might be sufficient. However, if the damage is extensive or if the floor is not level, it's best to replace the floorboards with a suitable material to ensure a solid foundation for your new herringbone flooring. Before proceeding with any flooring installation, it's always a good idea to consult with a professional flooring contractor or an expert in the field. They can assess the current state of your floor and provide personalized recommendations based on your specific situation Good luck with your project!

As long as the original floorboards are all fastened down. Replace any broken boards. This doesn't include cut boards,but do check the cut boards land on a joist. Any boards that do need replacing can be replaced using chipboard floor boards or like for like. Check no boards stick higher than others as it'll increase the chance of the over plyboards to follow creating a hump.

When considering the installation of herringbone flooring in your room, it's essential to assess the condition of the existing floorboards. If the current 18mm chipboard floorboards have significant cuts or damages, it's best to replace them rather than overlaying with 9-12mm plywood. Overlaying damaged floorboards could lead to an uneven surface and compromise the overall stability and longevity of the new herringbone flooring. Replacing the floorboards will provide a solid and level foundation for the new flooring, ensuring a smooth and professional installation. When deciding on the material for the replacement floorboards, you have a few options to consider. Like-for-like replacement with chipboard is a practical and cost-effective choice. However, if you're looking for an alternative material, you could explore options such as plywood, or solid wood boards. Plywood is a popular choice due to its stability and durability. It is available in various thicknesses, and 9-12mm plywood can be a suitable option for your project. Solid wood boards offer a more natural and aesthetically pleasing finish, but they may come at a higher cost. Remember, investing in a proper foundation and quality materials will contribute to the longevity and beauty of your new flooring, making it a worthwhile investment in the long run.