We received a lot of question about floor insulation and in order to help our clients we have dedicated this articles to the topic. Before we begin, though, let’s take a look at what are our floors made of.
The Structure of a Floor
Floors consist of three different parts. On the very bottom are the joists. They support the floor and everything on it. All houses but those with concrete slabs have them.
The second layer is the subfloor. It can be made from various materials like plywood, planks, oriented strand boards (OSB) or bare concrete slabs. It is the flat surface upon which rest the other floor layers.
The top layer, also known as finish floor or floor covering is the surface we see and walk upon.
What Is a Floor Insulation?
Floor insulation is a process which adds an insulating material between the top layer and the subfloor. The most common reason to insulate is to prevent heat from escaping the room. It is estimated that no less than 15% of the heat is lost through the floor. It is certainly a good way to save a few pounds from bills. There could be other reasons for insulation, though.
The material used beneath the floorboards is called underlay and it can display various properties. It can protect from moisture, prevent squeaking, provide cushioning to make the surface more pleasant to walk upon or help make the floor more even and levelled as a whole.
The Things You Must Know About Insulation
Underfloor insulation always involves removing your already laid hardwood floor, installing the underlay beneath it and finally relaying your floor back!
There is more than one method of thermal insulation. It’s possible to use a sealant to fill the gaps between the individual floorboards as well as between the floor and the skirting boards. This is called draught-proofing.
Carpet underlay and wood floor underlay are two completely different things! They cannot be used for anything but the flooring type they were intended to.
Before choosing an underlay you should measure the moisture levels in your subfloor. That level should not exceed 12%. If you install over a concrete subfloor, the majority of the times you’ll need an underlay with a built-in vapour barrier to prevent the moisture from reaching your top floor.
DPM and vapour barriers are two completely different things. Damp Proof Membrane, also known as DPM is a thick plastic sheet used to protect from moisture. It serves the same purpose as the vapour barrier but is not part of the underlay itself. It will also safeguard from moisture better. Manufacturers like Quick-Step make laminate floors with a built-in underlay. This makes the laminate easier to install but if you put it on a place with high moisture levels you’d need a DPM.
The fact that you can get an underlay doesn’t mean you really have to. One of the most common reasons to get an underlay is to protect the floor from moisture. Vinyl flooring, for example, is completely damp proof and simply doesn’t need an underlay. For this reason, vinyl is usually laid upon plywood.
About Floating Installations
Usually, hardwood floors are glued or nailed down to the subfloor. This improves their stability and reduces the sound made upon walking.
Floated floors, on the other hand, are not really a “type” but rather a “method” of installations where the boards, planks or tiles are snapped, glued or nailed together but not to the subfloor. The most common examples are laminate, luxury vinyl and engineered flooring (engineered can be both floated or fixed). Underlays are essential for any floating installation because the whole thing lacks stability and moves constantly due to seasonal humidity and temperature changes. The cushioning will ensure softer feeling with each step.