You have the top layer that is your floor covering (Hardwood, Laminate, Vinyl, Carpet, etc.), next you have the underlayment (usually a thin layer of fiber, foam, rubber), below that you have your subfloor (plywood, OSB, concrete), and lastly you have the joists which are the foundation to your floors.
Adding an underlayment layer on top of the subfloor is a great practice. It allows the subfloor to not be directly bonded to flooring that may be changed in the future. As remodelers, we try to always build with the future in mind. #bathroomremodel #subfloor #underlayment #remodel #tipsandtricks #remodeltips #remodel.
You can fasten your plywood underlayment using one of the following: galvanized, coated chisel-point staples with a 1/4" maximum crown; galvanized, coated ring shank underlayment nails with a 3/16" diameter head; or flathead wood screws treated with a moisture-resistant coating (such as galvanized or zinc).
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 right fasteners ensure that you're compliant with building codes and the warranty, and they prevent damage or premature weakening of the roofing system. For Epilay's synthetic roofing underlayment, approved fasteners include: Corrosive-resistant roofing nails with 3/8-inch heads. Plastic cap nails or staples.
Provided there is no rain or high winds, ProArmor® Underlayment can be anchored with staples, cap staples or corrosive resistant 3/8 inch head x 1 inch leg roofing nails (ring shank preferred, smooth leg acceptable), when covered with primary roofing on the same day.
Many roofers will tell you that staples are fine for installing the synthetic underlayment. Others will tell you that cap nails are more effective. Both options often depend on the slope of the roof itself. Cap nails are typically made of steel and feature a plastic cap to prevent roof leaks, hence their name.
Therefore, because concrete is porous, it's a good idea to install a vapor barrier over your concrete subfloor before installing your flooring. This way you can stop the vapor drive of water upward to your floors, protecting them from any damage (source).
Underlayment is a special grade of APA plywood that is attached on top of the subfloor to provide a durable and resistant layer under finish flooring. Underlayment's special face and inner-ply construction resist dents and punctures from concentrated loads.
Underlayment screws are specifically designed for fastening wood underlayment to wood subflooring. These screws have an intricate thread pattern that tightly holds the two flooring layers together to prevent squeaking, which is one of their advantages over nails and staples.
Underlayment tapes are used during the laying of underlay and have many advantages for the fitting process, including how readily available it is and how cheap it is. Duct tape can be used when fitting underlay under the carpet.
If your choose this route, staples are a good choice to fasten the underlayment. Staples usually have a coating which help increase the holding power.
With that being said, most underlayments are 2-3mm thick, but are sometimes thicker for carpet or to smooth out an uneven subfloor. It's often advertised that 6mm underlayment offers double the sound absorption as 3mm underlayment.
An interior stud wall can be set right on top of your new DRICORE® subfloor and is in fact, the preferred method of installation. Install your 2X4 frame directly on top of the subfloor, measuring for a "snug" fit between the subfloor and ceiling.
Using code-approved screws rather than nails is the best option for avoiding movement. If using nails for subfloor installation, stick with ring-shank nails; smooth nails may withdraw easier, leading to squeaks.
Fasten the underlayment with either staples or nails. Start on one corner of the panel and fasten the 8' edge first, spacing 2” along the entire edge. Make sure the fastener is around 1/2” from panel edge. Go back to the starting corner and repeat the process along the 4' edge.
Grip-Rite 114ATUL1 1-1/4 in. x 12-1/2-Gauge Bright Steel Broad Head Ring Shank Underlayment Nails are designed for indoor use where corrosion isn't a concern. Thin, broad head ensures a smooth finished surface and strong grip when attaching plywood or subfloor materials.
Because a vapor barrier is a low permeable barrier, it keeps moisture from passing through. This is beneficial to keep moisture away from a dry surface but will trap moisture behind it if installed on a water-damaged concrete wall, causing the wall to fail further.
Moisture and mold protection
An underlayment that offers a vapor barrier is essential to protect any flooring installed over a subfloor that emits moisture, like concrete. A thin foam underlayment made of polyethylene or polypropylene usually works best.
Location: Floor underlayment is positioned between the subfloor and finished flooring, whereas floor vapor barriers are typically installed beneath the underlayment or directly on top of the subfloor, depending on the specific requirements of the flooring system.
This kind of underlayment is commonly called tar or felt paper and can either be made with natural materials, such as wood cellulose, or synthetic materials, like polyester or fiberglass. The base materials are then soaked in a protective coating made of bitumen (asphalt) or something similar.
To nail down the plywood, use underlayment nails, which have a smaller head and rings on the nail shank that prevent them from working loose. Drive nails throughout the entire sheet of plywood, every 6 to 8 inches (see illustration on next page), to ensure the floor is down solidly.