Restora Obscura

After weeks of research on cedar shingle treatments and testing four products (see: "Preserving the Aging Shingle"), I had enough information to write a book on the topic (well, a lengthy blog post, anyway) but still felt that there was no obvious best choice. A TWP formulation that appeared to last about a decade in this Mediterranean-like climate seemed to be the better of the bunch, but it was still a far cry from the forever-lasting creosote stain that was available when Comstock House was built.

But as I was about to make a decision, Kelly-Moore sales rep Greg Fitch asked why I hadn't looked into TWP's 200 series, which is made specifically for shakes and shingles. Mistakenly, I assumed that the product was either discontinued because no stores carried it, or it wasn't legal in California -- after all, the stuff was 93% solids, far higher than anything else on the market. A call to the distributor revealed that not only was it available in the state, but that they sold quite a bit of it in Marin County. From him I also learned of the Marin Wood Restoration and Painting Company, which offers an extremely helpful web page on how they blend different TWP formulas (don't miss their photo gallery). The drawbacks are that this treatment takes longer to dry -- no problem here, since I'm hand-dipping each shingle -- and requires extensive stirring; a tar-like layer settles in the bottom of a can after only a few hours. The shingles also dry to a considerably lighter color.

Thus armed with new info, I ordered three cans of TWP and began experimenting afresh.

My new test panel had 7 samples, shown below. As with the first set, these shingles are all Maibec grade A white cedar. These shingles were dipped in different recipes containing TWP 203 (gold), TWP 200 (clear) and TWP 515 (cedar, which was tested by itself in the first panel). The clear formula offers no UV protection, but is used to lighten other formulas while still providing the non-colorfast wood preservation benefits of the other TWP 20x product line.

The shorthand recipe is shown in parentheses; (1-2-3) means 1 part gold, 2 parts clear, and 3 parts cedar formula, for ex. Because the TWP 20x products lighten in color, the test panel below was photographed ten weeks after dipping, except for shingle 2A, which is a freshly dipped shingle with the same recipe as shingle 2.

1: Just TWP 203 (1-0-0)

2: Equal parts gold and clear (1-1-0)

2a: Equal parts gold and clear. but newly applied (1-1-0)

3: (2-1-0)

4: (1-0-1)

5: (1-0-3)

6: Equal parts of all (1-1-1)

7: (1-1-2)

Curiously, the only significant color change appears when mixing the clear formula with cedar, as shown in samples 6 and 7. Our final choice was recipe two, an equal mix of TWP 200 and TWP 203. So far, it looks pretty good; we'll see.