How is a wood front door refinished?

Why most door finishes fail

A front door takes more abuse than any other piece of wood on a house. Sun hits it at a low angle in the afternoon, it swings through a damp morning and a hot afternoon every day, and people touch it constantly. Most doors were finished once at the factory and recoated, if at all, by brushing a quick coat over whatever was there.

The failure usually starts low on the door and at the bottom edge, where water sits, or on the horizontal rails where the sun cooks the finish. Once the clear coat clouds, cracks or lifts, water reaches the wood and the stain under it fades to gray. The door we refinished for a homeowner in North County had gotten to exactly that point: gray, dry, and losing its finish in sheets.

Step one: take it apart

We take the door off its hinges and set it flat on horses in a shaded, dust-free spot. Working flat lets the varnish level and keeps it from running. We remove the lockset, deadbolt, hinges, kick plate and weatherstripping. Taping around hardware never produces a clean edge and leaves old finish under the plates to fail later.

If the door has glass, we protect the glass but strip right up to it. Caulk or glazing that is failing gets replaced at this stage.

Step two: strip and sand

How much stripping a door needs depends on what is on it. A failed clear coat over stain can often be sanded off directly, working from a coarse grit up through medium and fine. Thick or painted finishes get a chemical stripper first, then a wash, then sanding.

On a paneled door we sand the flat panels and rails with a random-orbit sander and do the profiles and raised moldings by hand with a block, always with the grain. The goal is bare, clean, uniformly open wood with no shiny patches of old finish, because stain will not penetrate those spots and they will show as light blotches.

We finish the sanding at a medium-fine grit, not a polished one. Wood sanded too smooth will not take stain evenly.

Step three: condition and stain

Many door species, and especially fir, alder and pine, blotch when stained. A pre-stain conditioner partly seals the thirsty areas so the stain goes on even. We test the stain on the top edge of the door or an inside face before committing to the whole door.

Stain is wiped on and wiped off, then allowed to dry fully. Rushing this step traps solvent under the varnish and the finish never hardens properly.

Step four: build the varnish

This is where the time goes. A spar or marine varnish with UV absorbers is applied in thin coats, each one scuffed lightly with fine paper once it is dry so the next coat bonds. Four to six coats is typical for an exterior door, and the first coat is often thinned so it soaks in and anchors the rest.

We coat every surface: both faces, both long edges, the top, and the bottom. The bottom edge is the one most finishers skip because nobody sees it, and it is the one that wicks water every time it rains.

Step five: reassemble and plan the recoat

After the final coat cures, the hardware goes back on with fresh weatherstripping, and the door is rehung and adjusted. A refinished door is not a one-time fix. The varnish needs a light scuff and a maintenance coat before it clouds, which on a protected door might be every couple of years and on a sun-blasted one may be annual. We cover that schedule in its own answer.

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