Installation method is usually settled on site, but it should be settled before the order is placed. The way the floor will be fixed down narrows the construction, sets a practical range of thickness, influences how wide the boards can sensibly be and decides whether a tongue and groove or square-edge profile is appropriate. When a buyer specifies the board first and asks the installer later, the board sometimes has to change, and a sample has to be made twice. This article sets out how each common method relates to the specification, and which party makes which decision.
Who decides what
A flooring order involves three parties with different responsibilities:
- The installer assesses the subfloor, chooses the installation method and follows the installation guidance for the project’s location. The installer also sets acclimation and site conditions.
- The adhesive or fastener maker sets the rules for their product: which adhesive suits which subfloor, how it is applied, which fasteners and spacing suit which board.
- The factory builds the board to the agreed specification: construction, thickness, width, profile and finish, made consistently across the order.
The factory does not choose the installation method. It needs to know the method so the board it builds suits it. The NWFA publishes installation guidance that installers widely reference, and it is a useful common reference when buyer, installer and factory need to agree.
Start with the subfloor
The subfloor decides which methods are available.
- Wood subfloors, such as plywood or boards over joists, accept mechanical fastening. Nail-down and staple-down installation depend on a subfloor that can hold a fastener.
- Concrete slabs cannot hold a floor nail, so the floor is normally glued down, or laid over an underlayment where the board and method allow it.
- Existing floors and renovation work often bring floor-height limits, uneven surfaces or mixed subfloors between rooms. These usually point to a thinner engineered build and a method the installer can apply consistently across the whole area.
If the project has more than one subfloor type, list each area and its subfloor in the RFQ. It may lead to one board used with two methods, or to two builds.
Nail-down
In a nail-down installation, fasteners are driven at an angle through the tongue into a wood subfloor. The tongue and groove joint then holds the next board in place and hides the fastener.
What this means for the specification:
- Construction. Both solid and engineered boards can be nailed down where the installer approves it. Solid oak is the traditional nail-down floor and is best suited to narrower boards.
- Thickness. The board has to be thick enough for the fastener the installer intends to use, with enough material above and below the tongue. The installer and fastener maker confirm the minimum; state the installation method in the RFQ so the thickness is chosen with it in mind.
- Profile. Nail-down depends on the tongue. A square-edge board has no tongue to fasten through, so it is not a nail-down product in the usual sense.
Glue-down
In a glue-down installation, the board is bonded to the subfloor with a flooring adhesive spread across the surface. The adhesive maker specifies which adhesive, how it is applied and what subfloor preparation is needed.
What this means for the specification:
- Construction. Engineered boards are commonly glued down, including over concrete. Solid boards can be glued in some situations, but they are more demanding about subfloor conditions, and the installer and adhesive maker should confirm it for the project.
- Width. Full-spread adhesive holds the whole underside of the board, which is one reason wide engineered boards are often glued down. The installer confirms the method for wide boards on the specific subfloor.
- Profile. Both T&G and square edge can be considered for glue-down. With square edge, the adhesive and the subfloor flatness do all the work of holding boards level with each other, so the installer should confirm it before the order.
- Backing. Tell the factory if a specific adhesive is planned. The underside of the board is part of what the adhesive bonds to.
Floating
In a floating installation, the floor is not fixed to the subfloor. It rests on an underlayment and is held together by its own joints, with an expansion gap left around the perimeter.
Our Tongue & Groove profile is machined on all four sides and is intended for glue-down or nail-down installation. If a floating installation is being considered, raise it before the specification is fixed, so the installer, the buyer and the factory can agree whether the board and method suit each other. It should not be assumed from a quotation that was prepared for a different method.
Method and specification at a glance
| Method | Usual subfloor | Construction to discuss | Profile | Confirmed by |
|---|---|---|---|---|
| Nail-down | Wood subfloor that holds a fastener | Solid (narrower boards) or engineered | T&G | Installer, fastener maker |
| Glue-down | Concrete or wood subfloor | Engineered; solid where approved | T&G or square edge | Installer, adhesive maker |
| Floating | Over underlayment | To be agreed before specification | To be agreed before specification | Installer, with the factory |
How method connects to construction and width
The method and the board have to be chosen together:
- Solid is best suited to narrower boards and to projects where repeated sanding and refinishing is a priority. It is more demanding about the subfloor and site conditions.
- 2-layer engineered is a sawn oak wear layer on a stable plywood core, and a practical choice where floor height is limited. It is commonly used for herringbone and chevron.
- 3-layer engineered has a cross-layered core and a backing layer, and is well suited to wider boards and larger open areas where dimensional stability matters.
Our standard builds are 5/8” (15mm) overall with a 3mm sawn wear layer and 3/4” (20mm) overall with a 6mm sawn wear layer. Other thicknesses from 3/8” (10mm) to 13/16” (21mm) are made to order. The solid vs engineered guide and the 2-layer vs 3-layer comparison cover the construction decision in more detail.
If the floor will run over radiant heating, the heating system maker and the adhesive maker add their own limits. See engineered oak flooring over radiant heating.
Profile and pattern floors
Herringbone, chevron and parquet add another layer. Blocks meet at angles, so the profile on the ends matters as much as the profile on the sides. With T&G on all four sides, each block engages its neighbors mechanically. With square edge, the floor depends entirely on the adhesive and on a flat subfloor. For pattern floors, agree profile and method at the same time. Our article on T&G profile accuracy explains what to check on the profile itself.
What to put in the RFQ
- The installation method for each area: nail-down, glue-down or floating (to be agreed).
- The subfloor type for each area, and any floor-height limit.
- Whether radiant heating is present.
- The adhesive or fastener system, if already chosen.
- Profile: T&G on four sides, or square edge.
- The installer’s name or company, if the installer will be asked to confirm the sample.
A board that suits its installation method starts with this information. It costs one paragraph in the first request and can save a second sample later.
Working with Vu Uy Wood
We manufacture solid and engineered French White Oak flooring to buyer specification in Song Than 3 Industrial Park, Ho Chi Minh City, and have done so since 2006. Our Tongue & Groove profile is machined on all four sides on HOMAG equipment, with square edge available on request, and the full route from drying to profiling is shown on our Production page. Tell us the subfloor and installation method along with your selections on the Specify page, and the specification is reviewed with them in mind. We normally reply within one working day.