As mentioned above, the National Wood Flooring Association (NWFA) explicitly recommends not using rosin paper with hardwood flooring. The reason is that rosin paper does not function well as a moisture inhibitor.
Felt paper is installed under hardwood flooring to provide an extra layer of moisture protection and also to dampen sound. You will need to install it under your wood floors if a padding is not already attached to the hardwood planks. Many models of hardwood planks have dampening foam already attached.
Do I need a vapor barrier for hardwood floors?" The answer is YES! Moisture can destroy hardwood flooring. It causes cupping, warping, and even mildew if not treated. You must install a moisture barrier to protect your flooring from water wicking up from below.
Things You'll Need
Rosin paper is a multi-purpose building paper used underneath hardwood floors as an underlayment. It is used as a moisture-barrier and it allows the wood floor above it to breathe. The paper is installed just before the wood flooring and comes in rolls of various lengths.
A subfloor, which is usually made of wood panels, must be installed first, before any other layer, and you must also install what is called an underlayment. Underlayment is the layer of material that sits between the subfloor and the new hardwood flooring.
A slotted underlay can be used with solid wood flooring or engineered wood flooring. Glue is applied into the slots of the underlay using a barrel gun which helps make the application quick and mess free. The wood flooring is then fixed on top and held to the subfloor by adhesive through the slots.
If the subfloor is plywood, opt for an underlayment that's semi-permeable. This type of underlayment allows both the hardwood floor and the wood subfloor to breathe without trapping mold and mildew or causing the material to rot. If the subfloor is concrete, choose an impermeable underlayment instead.
When used as an inner liner in wall, roofing, or wood flooring applications, RED ROSIN PAPER acts as a separation barrier, protecting against wind and dust infiltration, while minimizing squeaks. It is compatible with coal tar and asphalt-based roofing systems.
Felt and red rosin paper are both often used as moisture barriers when installing hardwood floors. While each of them do have an intended purpose, they are not the best suited products for hardwood floors. Red rosin in particular actually traps and holds moisture.
Roofing paper should not be used under hardwood flooring. Due to its bituminous materials, it could begin to exude an unpleasant odor and even be toxic for your family. Instead, rosin or felt underlayment paper is appropriate.
One of the best and easiest ways to protect your hardwood flooring from water damage is to lay down mats and rugs throughout the house. Place mats at the entrances to your home to keep wet, muddy shoes from traipsing onto your floors, and put a mat at the base of any sinks to protect your flooring from splashing water.
When installing wood flooring, solid or engineered, on a concrete base the use of a damp proof membrane is always recommended. No matter how dry your floor feels it will always contain damp, which can be drawn to the wood if not treated causing cupping, lifting and general damage to the floor.
Very often, particularly in a below-grade installation on a concrete basement floor, a vapor barrier is recommended in addition to the underlayment. That vapor barrier would go between the subfloor and the underlayment.
The wax paper provides a professional grade thickness and performance to help ease the installation and reduce squeaks in wood floors. The wax paper is simply placed between the subfloor and the wood flooring on above grade installations.
Felt underlayment for hardwood
These help keep moisture from coming up through the subfloor even when you nail directly through it, and can be stapled to the subfloor so they stay in place. Black felt underlayment looks a lot like roofing underlay but does not have any asphalt or tar.
The only correct choice for a vapor retarder is a building paper that meets UU-B-790. Roofing felt, rosin paper, and plastic vapor barriers are poor substitutes.
Builder's Paper is slightly more expensive per roll than Rosen paper, but it's quite a bit more durable. Like rosin paper, It also works well as a paint paper. Builders paper is the color of a brown paper lunch bag. Its thick enough to use on floors in areas that will see light traffic.
Red Rosin Paper
Tried a true, Red Rosin is the old school underlayment paper used under real wood flooring. It's extremely low in odor and even that dissipates rather quickly. The extremely sensitive almost always do well with this, with only a few people mentioning that the undyed Rosin Paper was preferred.
As mentioned above, the National Wood Flooring Association (NWFA) explicitly recommends not using rosin paper with hardwood flooring. The reason is that rosin paper does not function well as a moisture inhibitor.
LIMITATIONS: Fortifiber Red Rosin Paper is not flame-retardant, a vapor retarder, a moisture barrier and is not waterproof. Avoid use in high moisture areas.
Underlayment for laminate flooring is a must. Since laminate is a floating floor, it must be evenly distributed across your subfloor. Underlayment is what allows the floor to float, gives it stability, support, noise reduction, and supports the locking systems in between planks to assure the sturdiest flooring project.
Solid hardwood floors must be fixed into position by either gluing or nailing down to the subfloor. Engineered hardwood floors can be glued or nailed into position, but they also have the option of being floated over an underlay.
Ranging from a relatively fine 2mm thickness, this option exists up to a thickness of over 5mm and can be used for all types of wood flooring. Insulating underlay. Insulating underlay is a bit like duvets and comes with a Tog rating.
Underlayment. You should always install engineered wood over an underlayment. Moisture barriers and underlayment prevent moisture build-up under your floors, keep your floors warm, reduce noise, and even out subfloor imperfections.