Many words have been written on this site about the sustainability of various sheet flooring materials available, comparing plastic surfaces like vinyl with more natural options like lino. But it is important to look at the flooring as a whole and that includes the supporting layer that often has to go down before the sheet flooring.
The Importance of a Good Base
It is important to have a flat surface underneath sheet flooring, regardless of whether it’s vinyl or lino. This is because these flooring materials are relatively thin and any imperfections from the supporting surface will translate into ridges or dips in the sheet flooring.
If there is an uneven wooden floor, for example, lines will appear along the edges of the floorboards. When people walk across the floor this ridge will take more than its fair share of wear and could lead to a split appearing in the flooring in very short order. It is for this reason that a flat base needs to be laid down first.
Looking at the Underlying Floor
Many rooms that have sheet flooring, like kitchens, halls or toilets, are on the ground floor and may have a concrete base and screed. In this case you can lay down sheet flooring without having to put a base down but you must get rid of any imperfections first. Use a cold chisel to chip off any ridges or raised knobs of concrete before putting the sheet flooring down.
Assuming the rooms you are going to lay sheet flooring in do not have concrete floors you’ll be looking for way to level the floor. This usually achieved by laying down large, flat boards and the traditional options are hardboard, plywood or boards constructed from wood by-products like oriented strand particle board (OSB). But which one has the best sustainability record?
As ever, with sustainability and ecological issues, the answer is varied and at some times contradictory. Looking at illegal logging and the use of precious rainforest resources, plywood is getting a lot of pressure from groups like Greenpeace over the provenance of the wood. Plywood is made from thin sheets of veneer peeled off the wood and glued together in layers that criss-cross to give strength.
Much of the plywood in use in the UK, particularly the large sheets used in construction, which are nearly all thrown away after each project finishes, are thought to come from illegally logged forests. Assuming you can find plywood that is FSC certified then that is more sustainable than an uncertified product. But because the sheets are peeled off the main trunk of a tree, plywood is in any case considered more destructive than some of the other alternatives.
Hardboard is one of those alternatives. It has been around for quite a long time and is made from small wood fibres that would otherwise be thrown away. Because it is made by compressing the fibres together without glue (although resin is occasionally added) it is largely non-toxic. Modern day hardboard is often made from recycled wood and paper pulp, increasing it’s attraction as an environmentally sustainable product.
Usually it comes with a rough side and a smooth side, so laying it down with the smooth side uppermost makes it a perfect sheet flooring base. Being quite thin it is also quick to lay, as it can be stapled rather than nailed or screwed.
Oriented Strand Particle Board
Sitting between hardboard and plywood, in both sustainability and construction method, is OSB. Variously known in the UK as SmartPly or Sterling board (both of which re actually trade names), the chips needed to make the board are considerably larger than those used in hardboard, being about an inch wide and three to four inches long. But they are still chips, rather than the large sheets of wood used for plywood. The chips interlock, lending strength to the board, in the same way that plywood does but on a far smaller scale.
The advantage over plywood, in sustainable terms, is that smaller branches can be used instead of being discarded, making far more use of each tree. In addition smaller, younger and faster growing trees can be used, reducing the demand for slower growing hardwoods and firs. The chips are laid in layers like plywood then compressed like hardboard A small amount of resin-based glue is added, usually comprising around 5% of the boards’ content.
Assessing the Options
As previously stated, determining the sustainability of any product can be a minefield and the base for sheet flooring is no different. At the moment it looks like hardboard comes first, OSB second and plywood third. If you have to go for plywood try to reuse some discarded from a construction site or make sure it’s FSC certified if you have to buy new.