Examining the details of floor underlay

I had a wonderful email from a lady last week asking me about all sorts of things that she wanted me to write about. Some topics I have already covered but she asked about underlay which I don’t think I have ever written about because I think people might find it boring.

I may have overlooked that people actually do want to know about underlay! In the past week I have really started listening for that question from my clients and guess what….yup, people are asking about underlay!

So we dive into the exciting world of underlay and under pad, brace yourself – this might require a cup of coffee. To make it not so technical let me give you the ground rules; anything that is glued down requires subfloor of some kind. This includes hardwood, vinyl, tile; anything floating requires pad or some sort of liner underneath. Carpet would fall under the ‘floating’ category because technically it isn’t adhered to the product beneath it. The only place this rule is sometimes broken is on concrete floors as it provides a suitable underlayment for almost any glued down or floating product.

Carpet under pad comes in a variety of products, from chip foam to memory foam to solid rubber. You can choose your under pad and choose your price point as it best suits your project. You should be choosing solid under pad if you have in-floor heating in your home as it has warranty for this type of installation. Constant heat on chip foam under pad can dry out the chemical bond between the foam pieces and can cause your underlay to fail prematurely.

Under pad is also available for any type of floating floor including hardwood, laminate and vinyl plank flooring. These floors require foam or cork underlayment to provide a barrier between the product and the hard floor underneath. Some under pads also come with a plastic layer known as a vapor barrier which is used when floating a product over concrete floors to help prevent moisture damage.

I think where most people get confused is between subfloor and underlay. These are industry terms which I know we in the ‘biz’ toss around like everyday vernacular when in reality most people have NO idea what these terms mean.

Subfloor is the product (typically OSB or plywood) that is adhered to the joists, some products require and additional layer before installation. Underlay comes next and is either a layered plywood or particle board depending on what you are installing. Vinyl is typically installed on a smooth particle board product while ceramic tile is put on top of plywood. Both of these underlayments provide stability and the proper thickness required to prevent movement.

When you are gluing a product down to an underlayment, stability is crucial because the product can only follow the underlay it is adhered to – if there is movement in the floor there will be movement in your product causing cracking and lifting.

The things that go under our floors are not that exciting but they are necessary for a long and happy relationship with your floors and deserve as much time, attention and knowledge as your beautiful ceramic tile!

Kim Lewis is an interior designer in Red Deer with Carpet Colour Centre. Contact her at 403-343-7711 ext. 227 or email her at klewis@carpetcolourcentre.com.