It’s a questioned often asked and pops up frequently in online discussions. Can a wood floor be installed straight on top of an old parquet floor? Well, the answer is clearly going to be subjective, but within the contents of this article I’ll be giving you a little of the basic science of why you should not install a wood floor on top of an old parquet floor..Read on..
Some typical and critical information you should know about old parquet wood flooring
Parquet wood block floors have been in high demand from the mid 1800’s. A popular option for fixing them onto concrete sub-floors was with the use of bitumen adhesive. This type of adhesive had a double purpose. Early concrete sub-floors (all the way up from the mid to late 1960’s) were installed with no means of preventing them wicking moisture from the earth beneath. Common methods of moisture protection now-a-days being with the use of thick visqueen/plastic sheeting placed beneath concrete slabs. Prior to the mid 1960’s, parquet floor installers relied on the moisture blocking properties of bitumen as a barrier from moisture that would inevitably be drawn through the concrete slab, as well as using bitumen as a means of securing the blocks in place.
This was an effective method during those years, however, there was a problem with using bitumen adhesive. It perishes over time. In other words becomes extremely brittle and/or looses its strength. Which of course is to be expected when we’re talking about a material that in some cases is over 100 years old. Parquet wood block flooring moves. That is to say it expands and contracts with seasonal atmospheric changes. When the blocks expand or contract, they are applying a sheer force against an often already weakened or perished bitumen adhesive, resulting in tears/cracks/splits developing in the bitumen layer. This of course, then allows moisture from the unprotected concrete to pass.
Wood is a hardy material and will often allow low levels of moisture to pass with little or no obvious clues. Hence, many aged parquet wood floors are immediately looked at as a good sound sub-floor on which to install a wood floor. However, with the information above in mind, there is a problem..
Why you should not install a wood floor straight on top of an old parquet floor!
Everything looks fine with your aged original parquet floor. Then you install a wood floor over the top. For instance a ‘floating’ engineered wood floor, laminate, or even ply board sheeting in preparation for a Luxury Vinyl Tile.
This is often where the problems start. Sometimes within a few weeks, sometimes with a few years.
When a wood floor is installed on top of a parquet, you’re essentially putting a lid on a simmering pan. Blocking the transference of moisture from the original concrete through the parquet. This is of course providing the bitumen adhesive has failed. I’ll tell you now, an aged bitumen wood block adhesive is rarely, if ever, in tact after twenty or thirty years plus!
When our metaphorical lid is placed on top of an old parquet floor, the moisture can build up. Immediately, the parquet blocks will start to absorb this moisture like a sponge. Resulting in the blocks expanding, again, a lot like a sponge. This will typically only happen in localized areas, where the breaks are in the bitumen. Although, if the bitumen is in a very bad state, the entire area can become wet. Regardless of this effect happening in localized areas or the entire floor, Murphy’s law will inevitably kick in. As the blocks expand excessively, the accumulative effect of the expansion will come to a head. In other words, the expanding blocks will hit either well fixed wood blocks and/or perimeter objects such as walls, door casings etc. With nowhere to go, the blocks will give at the least point of resistance, and lift. This is also known as ‘tent’ or ‘tenting’. This tenting will push the new wood floor – on top – upwards. Resulting in an extremely undesirable and frankly unlivable wood floor that will without any shadow of a doubt require removal.
Should you be one of the lucky ones, and your floor doesn’t tent, you can often look forward to years of rotting wood and mouldy damp smells.
Do not take the chance and install a wood floor, of any kind, on top of an old parquet block wood floor. You have been warned!© Copyright 2015 Wes, All rights Reserved. Written For: Fitmywoodfloor