5.5mm plywood flooring grade SP101 and FG1. Why you need them!

by Robert Barney on Nov 04, 2023

5.5mm plywood flooring grade SP101 and FG1. Why you need them!

If your home has a wooden underfloor, the initial steps you take can significantly affect the outcome when you decide to install safety vinyl, marmoleum, LVT, or even often wood flooring. The cornerstone of achieving a polished, professional finish lies in preparing a stable subfloor. A common pitfall for many amateurs delving into flooring projects is the lack of adequate preparation, paired with an overzealous desire to dive into what is perceived as the 'fun' phase - laying down the top floor. However, a crucial step that can't be skipped is ensuring the subfloor is flat. In the flooring world, our aim is to flatten floors, not level them—that's a task reserved for builders. Without a flat subfloor, the final result is inevitably a subpar floor.

Today, for instance, the project undertaken by our friends at Cavendish deVere involved repairing and plyboarding a floor for a client located in Balham SW12, London. The process entailed cutting the plyboard to the precise shape, fitting it snugly, and securing it firmly using coil nails. Once the plyboarding was complete, the next phase was to prime the surface, followed by the application of a self-levelling latex screed. The drying phase of the screed is vital; although it usually takes a few hours, it's often left to dry overnight. This drying duration can be influenced by weather conditions and the internal temperature of the property. Once dried, we returned to give the floor a final sanding, which leaves a smooth surface that now stands ready to welcome the top floor.

This method is considered to be optimal. An alternative could be to use a feather finish to cover the cracks between the plyboards, which might save some expenditure on screed. However, latex screed is preferred for its superior finish and its ability to flex with micro-movements in the subfloor. The flooring-grade plyboard is crafted to be rigid, minimizing flexing, which in turn reduces the wear on the adhesive that bonds the top floor to the subfloor. This meticulous approach ensures a longer-lasting floor, preventing issues like bubbling and the top floor detaching from the subfloor.

An important consideration we always communicate to our clients concerns homes with two different underfloors— for example, one part being concrete and the other wood. Over time, a wear layer may manifest due to the wood's slight flexing and micro stretching of the top floor. While this occurrence is natural, it can be mitigated by having a uniform type of underfloor, although this solution may not always be practical and could prove to be quite costly.

Each step of this process underscores the importance of thorough preparation and the right materials to ensure a professional finish, affirming the adage that a good beginning is half the work done.