Hardwood Flooring and Millwork -- Finishing Options

Pre-finished or site-finished? November 16, 2001

Pre-Finished or Site-Finished?

Reprinted with permission from The Hardwood Council website.

Paths to Perfection: Finishing Approaches Vary

Most builders, architects and woodworkers agree that solid hardwoods like oak, ash, maple and cherry add beauty and value to a home. When it comes to finishing, however, opinions vary. The Architectural Woodwork Institute (AWI), for example, recommends pre-finished products for uniformity and superior appearance. Builders, on the other hand, may feel on-site finishing offers advantages in cost and project control.

The following offers a review of factors you can balance with your experience and circumstances in deciding which way to go.

Decision Points

Consider These Finishing Factors:

FactorsPre-finished Site-finished
Surface Quality/ AppearanceOften considered superior; multi-step process adds durability, visual appealDepends on site conditions, worker skills, time available
UniformityConsistent as it comes from supplier, but work and touch-up done on-site may match only with difficultyConsistent finish possible across entire installation. Field conditions may affect overall quality adversely
CostInitial material cost usually higherLower material cost; labor (finishing and installation) cost is additional
Jobsite ImpactInstallation less dependent on other work in progressTies up areas of site for days; impact of other work may compromise quality
Quality ControlTypically strictHigh standards may be hard to maintain in the field
Tasks On-site Installation Installation, repeated finishing steps, repeated drying intervals
Skill Level RequiredTouch-up onlyHigh

With Pre-Finished Materials

Pre-finished products offer consistent quality and quick installation, although not without a few tradeoffs. Here's why:

Controlled Environment
Manufacturers don't have to contend with the effects of other building trades working nearby. Dust, traffic, temperature and humidity are out of the picture.

The Right Tools
Pre-finishing operations work with low-pressure, high-volume spray guns and spray booths, so uniformly good appearance from piece to piece comes much more easily. Maintaining consistency across a whole installation is another matter -- when cutting and mitering expose fresh wood, a factory finish is difficult to match, and touch-ups are tricky if there's damage on a busy jobsite. Finish-matching is easier, however, if you ask the supplier for a touch-up kit. Most manufacturers will supply stains and coatings from the same batch used on your materials, with instructions.

A builder often finishes a project in three steps -- stain, seal, finish coat -- but a manufacturer can go through four, seven, even 13 steps. Additional sanding and extra finish coats add the richness and depth that homebuyers admire.

Pre-finished hardwoods can cost as much as $1.50 per linear foot more than unfinished products. However, there are several ways to look at the "real cost" question. While pre-finished materials cost more initially, builders can save during installation. Finishing a hardwood floor to factory standards in the field can tie up a worksite for five days; even finishing decorative millwork can take three days or more. You'll need a crew of finishers and extensive site preparation. Other work that could jeopardize the quality of the finish will have to stop, adding time to the construction schedule.

With pre-finished products, site preparation is simpler, and other trades can continue to work. A lone carpenter or painter can complete touch-up in a day or two.

If You Finish On-Site

Most builders still consider finishing hardwoods on-site the most practical alternative, especially for major projects like flooring, staircases and paneling. Attaining a high-quality finish on-site is possible, but it requires planning, time and careful attention to detail. That deep, glossy, pre-finished look takes more than the standard three steps. The keys are repeated sanding and multiple finish coats.

1) Let the wood adjust to the site. Unfinished wood needs protection from moisture and from extreme fluctuations in temperature and humidity. Before the materials are delivered, have all windows and exterior doors in place, and bring the house to occupancy level conditions. Make sure all new drywall and plaster have had at least a week to dry. Store the unfinished wood in the room where it will be installed for about a week, so it will be dimensionally stable when the time comes for installation and finishing.

2) Seal it. Solid hardwoods must be sealed on all sides, since moisture can pass through the back, edges or ends as easily as the exposed faces. To avoid shrinking, selling and other damage, you should pre-coat surfaces that you won't be able to reach after installation.

3) Smooth it. Sanding is critical to an attractive, durable finish. Items like paneling, stair rails or cabinetry usually require only light sanding. Hardwood flooring needs to be sanded at least three times, with successfully finer grades of paper. Vacuum the floor thoroughly after each sanding, and delay spot filling and other minor repairs until just before the final sanding pass.

4) Prepare the room. Once you've installed and sanded your work, the goal is to re-create, as nearly as possible, the finishing plant's environment. Keep dust to a minimum and maintain stable levels of temperature and humidity. Seal doorways with plastic film, and schedule other workers away from the jobsite. Mask off any surfaces you wish to protect.

5) Clean the wood. Before applying stain, wipe it down with a clean cloth dampened in mineral spirits to temporarily emphasize defects such as sanding marks. Smooth out any flaws that appear, then remove all dust with a brush, compressed air or a tack cloth.

6) Stain it. Apply stains generously with a brush, rag or lambswool applicator. Allow it to sink in for five to ten minutes, then wipe off the excess with a clean rag. Let the stain dry for 24 to 48 hours -- follow manufacturer's instructions.

7) Seal and finish coats. (See QuickTips) When the stain is dry, brush on the first finish coat and let it dry according to the manufacturer's directions. Drying or curing times will vary depending on type of finish you use. When it's bone dry, sand the surface lightly with 280-grit or finer paper. Remove the dust with compressed air or a tack cloth and brush on the second coat.

8) Sand and coat again. The second or third finish coat will usually give you the desired result.


Product Variables
The application may affect your finishing decisions:

Flooring Will be subject to minute inspection; must withstand much more wear than millwork or cabinetry. Finishing is usually considered the most troublesome and unpredictable phase of a floor installation project.

Millwork Requires on-site cutting, fitting and at least touch-up finishing whether products are pre-finished or finished on-site. Usually, at least some elements will be beyond reach of close inspection when installation is complete.

Cabinetry Top-quality finish is most easily achieved in the cabinetmaker's shop. Installation alone is exacting, labor-intensive.

Choosing the Best Stain
Experts suggest oil-based stains containing a pigment/dye combination that promotes even coloring, even in dense hardwoods such as oak and maple. Oil-based stains are convenient for large areas because they dry more slowly, giving the finisher more time to wipe off the excess stain.

Selecting a Finishing Coat
Most builders choose polyurethane for its durability. Unfortunately, polyurethane is not suitable for the multi-coat applications involved in some millwork installations. Woodworkers often prefer conversion varnishes or catalyzed lacquers for these projects because they dry quickly, saving time when multiple coats are required. In larger sections of decorative woodwork, however, they may dry too quickly.

No Spills
When brushing on flooring finishes, position the bucket so you're pulling, rather than pushing, it along. If the bucket stays on the same side of your body as the wet end of the work area, you'll be less likely to bump -- and possibly spill -- it as you proceed.

1999 The Hardwood Council

Reprinted with permission from The Hardwood Council website.