Restore Finish on Water Damaged Hardwood

Project Description

For a customer in Hope, BC, Canada we needed to restore finish on water-damaged wood parts of a staircase.

Water-damaged hardwood on staircase
Water-damaged hardwood on staircase

Damage as on the picture above occurred due to water condensation on a skylight in winter. The skylight is right above this staircase, there were occasional water droplets on a couple of boards below skylight.

So, we have water damage in 2 places: one shown on the photo above, and also on another board, where the damage is much smaller.

Partially sanded away water damage on wood board
Partially sanded away water damage on wood board

The total area that needs re-sanding and re-finishing is probably about 3 meters long max, however, the damage is concentrated to a very few small spots, as on the picture above.

We need to re-sand the damaged boards, and then re-apply finish. Now, because the original problem why water appears here is NOT fixed, I am thinking about using oil-based finish for exterior surfaces, not water-based finish used indoors.

Eventually, we may fix the source of the water problem by replacing the skylight. This is, however, another project, which we are not doing now. To re-iterate, a few drops of water may come down on really cool nights in winter, when internal humid in-house air condensates on cool skylight surfaces.

Completion Notes

Let's start with tools we need for this project. Here are three electric sanders.

Tools: electric sanders for restoring finish on hardwood
Tools: electric sanders for restoring finish on hardwood
Bosch rotating sander for restoring hardwood
Bosch rotating sander
Mastercarft oscillating sanding tool for restoring wood
Mastercarft oscillating sanding tool

The oscillating tool on the picture above is actually not a sander, but an multi-purpose oscillating tool. Unfortunately, I cannot recommend the Mastercraft brand, their tools are not great quality-wise, but having one of such inexpensive tools is better than nothing, especially for narrow places in between the boards like on the picture.

If you wonder what's wrong with Mastercraft - in the oscillating tool above, the electrical switch failed after approximately a couple of months of light use after purchase while I was working on residential hardwood floor project.

Now, let's see how this hardwood restoration project was done.

Sanding Damaged Wood

I sanded the boards with available sanders and by hand, where sander tools cannot reach. Pictures below illustrate the sanding part of the project.

Sanding water-damaged wood boards
Sanding water-damaged wood
Bottom water-damaged part of staircase after sanding
Bottom water-damaged part after sanding
Top water-damaged board after sanding
Top water-damaged board after sanding

Applying Finish on Sanded Boards

Next step is to apply 3 layers of oil-based wood finish allowing sufficient time to dry between the layers (overnight). Used gentle sanding between layers for smoothness. I used Varathane finish shown below.

Varathane oil based wood finish
Varathane oil based wood finish

We are done! Here is how the parts looks like after applying 3 layers of finish.

Restored after water-damage part of staircase after applying 3 layers of finish
Finished job - bottom part
Restored after water-damage top board after applying 3 layers of finish
Finished job - top part

Now it looks very much better, doesn't it?