Our underlayment options should not be glued. Simply roll them out on top of your subfloor as shown in the video above. However, you can choose to glue down our floors rather than float or staple them.
The underlay should be spray Glued down, taped joins and the carpet traditionally fitted. With regards to the laminate, no glue should be used unless stated that is a stick together product (rarely are!)
Do not lay out and fasten the whole floor! Fit panels into place first before fastening. 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.
Yes, gluing plywood to a subfloor can add strength and reduce the chances of squeaking. Use a construction adhesive like Liquid Nails and apply it in a zigzag pattern before screwing the plywood down. This helps to bond the layers more securely, especially in high-traffic areas.
If your underlayment doesn't have pre attached adhesive you will want to use underlayment tape, but duct tape works just fine too. Some people like to use tape over the pre-attached adhesive just to have an extra layer of protection.
You can cut sheets with a circular saw, jigsaw, table saw, or handsaw, just like any wood sheet material. While underlayment traditionally was glued down to wood subflooring, most manufacturers today recommend installing it without glue, which greatly simplifies the installation.
Secure rows by taping them together, this will keep your underlayment in place.
Typically, click LVT flooring is thicker than glue down but it is similar in terms of the layered construction including a wear layer and protective top layer. Some click LVT flooring includes a layer of underlay too whereas LVT glue-down flooring has no underlay due to the installation process.
If you are looking for a subfloor adhesive with a powerful, permanent bond, try Loctite PL 400 VOC Subfloor & Deck Adhesive.
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.
Floating Underlayment
Most flooring underlayment is installed floating on top of your subfloor. Installers usually lay the underlayment on the floor and start installing the laminate flooring on top. There is no fastening the underlayment to the subfloor.
Stick your underlay to your subfloor – use adhesive glue or staples to make sure that your underlay is firmly attached to your subfloor. Lay your carpet on top – Now you can have your carpet fitted on top.
Each piece of underlay should be laid side by side, with the edges butting up against each other but without overlapping, as this can create an uneven surface for the laminate. Remember to tape the seams together with underlay tape to keep the pieces securely in place and prevent any moisture from seeping through.
Use a good spray adhesive to stick the edges down and then go over with a staple gun to secure. If you're dealing with a concrete subfloor, use your adhesive instead. Once laid, tape up any joints using duct tape or similar to prevent the paper from moving or sliding out of place.
In high humidity areas, it is always better to glue down the floor since gluing down reduces the movement of the wooden floor when there is a change in the moisture level of wood due to change in humidity.
No, you should not glue down your underlayment. Underlayment is is a floating material, the same as your laminate flooring. In most cases, you should not glue or nail your underlayment down. You should always check with the installation instructions of the underlayment for proper installation instructions first.
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).
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.
Challenging installation
The biggest drawback to glue-down vinyl flooring is the complexity of the installation process. This method requires more skill, precision, and time compared to floating vinyl flooring. Most homeowners choose to hire a professional for glue-down installation, which increases labor costs.
Glue-down installation
Parquet flooring, Laminate, Luxury vinyl tiles, Engineered wood flooring are are available in glue-down method.
Tiles or planks that are glued down, however, need time to set. This process takes at least 48 hours. Like luxury vinyl, carpet and laminate that is not glued to the subfloor can be walked on immediately. Brands that must be glued down are not ready for furniture for at least 24 hours.
Before you install your underlayment and flooring, repair any hairline cracks in your concrete subfloor and make sure you level it out. Over a concrete subfloor, you need a Class I moisture barrier to prevent moisture from moving up and sitting beneath your flooring.
The underlayment should meet but not overlap, as overlaps in the underlayment result in bumps under the flooring. Duct tape the seam to hold the underlayment in place and help maintain the vapor barrier.
In the end, it's your decision if moisture protection and getting higher sound absorption is your goal. If not, then pre-attached underlayment will do it's job but at the minimum.