When the roof shingles were removed, we hoped to finally solve the last big architectural mystery of Comstock House - but what we found was completely unexpected, and has led to other questions we still can't answer for certain.
The puzzle concerned the rain gutter system in the front of the house. We knew that there were downspouts inside all three of the columns, which were (presumably) attached to the back of the original gutters, and the aesthetic goal probably was to avoid big ol' metal downspouts from spoiling the look of the otherwise all wood-and-window house. Nice, but drawbacks include the risk that heavy rains could overwhelm such an enclosed system and cause leaks inside the house (the architectural history of this topic was discussed in an earlier essay). However that system was designed, we believed it apparently wasn't very successful. Between the earliest known photo (probably 1905, a few months after construction) and the 1908/1909 postcard, a rainstop board appeared above the actual gutter, likely intended to slow the torrent of rain as it shoots down our steep-pitched roof. Even that didn't perform very well; during the heavy rains of 2009-2010, every downpour turned the front of the house into a waterfall.
Until the shingles were ripped off, it was unknown what architect Brainerd Jones had engineered, or whether he had left that problem to contractors Williamson & McKenzie. Aside from the gutter profile shown above, there was nothing specified in the blueprints or in the written specifications. Thus we were completely surprised to find ourselves staring at not one, but two pipes emerging from each downspout. It was the oddest thing that any of us had ever seen.
Each pipe was 1½ inches and had bent-up lead flashing, which suggested that both pipes once emerged from the roof. The lower one was clearly once attached to the gutter; but what purpose served the upper pipe?
One theory was that the roof originally had oversized dutch gutters (also called box gutters, yankee gutters or integral gutters). These were sometimes used in Victorian-era America and were part of the house structure, built between the end of the roof and the flat board fascia that is visible from the ground (good diagram here, if trouble visualizing this). In this theory, our pipes acted as dual drop outlets (or maybe, a drop outlet with an emergency overflow drop outlet). Logical, yes, likely, no. The monster-sized fascia covering this design would have to be at least 8" high, and nothing like that is seen on the early house portraits or in the blueprints.
Theory #2: When the original gutter system failed, they improvised a second gutter above it to help intercept the cascade, and what we thought was a rainstop was actually a trough gutter (AKA stop gutter or Yankee Barn gutter). It's an interesting possibility, but couldn't be true; the two pipes were made and installed when the house was being constructed.
So to paraphrase Sherlock, once you've eliminated the impossible, whatever remains - however unusual - must be the truth, and this is it: Each downspout had its own private air vent.
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Technically these are "back vents," and Brainerd Jones might have suggested that the contractor build these as part of his terse directions found on page 21 of the specs: "Vents from other fixtures, back vent where practical..." But the two big questions are A) was this design unique? and B) did it even work?
Researching this proved a great challenge; understanding turn-of-the-century plumbing is sometimes like trying to solve a crossword puzzle written in Ye Olde English. Terminology wasn't always the same as today (and sometimes descriptors meant the complete opposite), and there were a jumble of terms to describe the same thing. Quiz: Around 1900, what did they call the pipes that carried rain from the gutters? Possibilities include "downspouts," "conductors," and "leaders," sometimes mixed with a prefix of "roof" or "rain" or "water". When I discovered hyphens were sometimes used ("rain-water down-spout") and using that combination returned still more unique results in a Google book search, my brain popped a tiny aneurysm.
Victorians had the notion that a downspout could have multiple purposes. They could double as air vents for the sewer system, or rainwater could be diverted into regular waste pipes in the house, with the hope that a big storm would flush away grease and other clogs. Of course, if the downspout itself was clogged with leaves or snow, the entire venting system failed; sinks didn't drain and toilets didn't flush. That practice ended and you'll find many building codes from c. 1890 onwards adamant that "Rain water leaders must not be used as soil, waste, or vent-pipes." The emerging uniform building code also included two other points of interest to our mystery. There was a rule for downspouts concealed inside buildings, specifying that the downwpout be made of sturdy material and absolutely watertight with the gutter - a no-brainer, but it shows inner-wall downspouts were considered an acceptable building practice. And at least from 1915 on, the Uniform building code required vents for each plumbing fixture, but specifically stated no vents were necessary on downspouts. That might have been included for completeness' sake, or it might suggest that some builders were venting downspouts, and the practice had come to be considered superfluous.
But after all that research, I could find only a single mention of an actual vented downspout. It appeared in a 1889 journal published by MIT, then reprinted the same year in the widely-read trade magazine, "American Architect and Architecture" (Volume 26). It described an ancedote told by New York's Chief Inspector of Plumbing, where a basement was flooded because the downspouts couldn't keep up with high water volume from a heavy rain. The problem was solved by adding an air vent to the downspout. Now the idea makes sense; vents allowed water to shoot down those pipes like a firehose.
So finally we're at the big question: Did Brainerd Jones' system work?
Engineering reference books in that era provided tables showing every calculation a builder would probably need, including the proper diameter of gutter and downspouts calculated for the size of the roof. The rule at this time was one square inch of downspout for every 250 square feet of roof area. With each watershed of the Comstock House roof covering roughly 2,000 square feet, the house needed eight square inches of downspout per side. The vented system here came up short. Each 1½ inch diameter pipe provided about 1.75 square inches, so all three downspouts together offered a combined 5.3 inches.
The other part of the calculation was the size of the gutter itself, and here either/or the architect or builder stumbled. The charts specified a gutter of eight inches wide; the redwood gutters used on Comstock House were the standard five-inch width, which we verified after finding a discarded cut in a crawl space, seen at right.But the undersized gutter wasn't the worst problem; we discovered that the middle downspout was never connected. The pipe was still sealed with a lead plug that would have been used during a plumber's smoke test for leaks. Considering the incredible speed of the construction of Comstock House, it's likely that the construction foreman didn't notice that the roofers had shingled over the plumber's mistake. The result was that the front downspouts could not have handled a watershed for a roof less than half this size.
Conclusion: The original rainwater system for Comstock House never worked. The gutters were too small, they needed an additional downspout, and one of the downspouts they had was permanently plugged. The rainstop was installed within a few years, but that didn't solve the problem either. Finally the entire system was abandoned; the redwood gutters were ripped out and replaced with a standard "ogee" five-inch sheet metal gutter, with three downspouts destroying Brainerd Jones' look. And despite all that, the gutters still couldn't handle the volume of water in even a moderately strong rain.
Hopefully our new system, which is over-engineered according to the period specs, will prove more robust. We'll see.
As noted earlier, no wood was supposed to be painted, inside or out, but there's at least two coats on the exterior trim. We'll strip that paint, of course, but what should replace it? What color would 100 year-old redwood be? I actually pondered this question for a couple of days before realizing that we had a house filled with examples.
But the question still wasn't easily resolved. The interior redwood trim varies greatly, from a rich brown to medium tan, some with yellow tones of old pine and some as red as cherry. Sunning can be blamed for fading in a few situations, but not all; this issue and its remedy needs further study. So we're back to a variant on the original question: What color SHOULD 100 year-old redwood be?
To experiment, I took a sill from a basement vent that was badly rotted underneath and needed
to be completely replaced (shown to the right, just for reference sake). Stripped of the remaining paint and thoroughly sanded down, the old redwood on the top of the sill had a color that might be called "Martian Sand."
Jones' specifications required that "one good coat of Pure Boiled Linseed Oil" should be applied first. The 1905 carpenters were working with fresh redwood, of course, which had a different nature than what remains now a hundred years later. To test how linseed oil would interact with the old wood, four test areas were sectioned with painter's tape dividing them, following with the application of 1, 2, 3, and 4 coats of oil as shown below, left to right. (Some of the linseed oil leaked under the painter's tape, but the test areas are still distinct.)
With a third and fourth coat of linseed oil, the wood became darker and more of the red color
came out, as seen in this closeup of the wood with 4 coats.
I also used this opportunity to test the waterproofing ability of linseed oil, placing a drop of water on each test strip and on the bare wood. On the untreated surface the water was absorbed almost immediately, within 15 seconds. The beads retained their shape for 30 minutes on the 1-coat strip, and for 50 minutes on the 2-coat strip. For both the 3 and 4 coat sections it took about 70 minutes for the drops to disappear. Conclusion: Linseed oil is a terrific weather protector, but there are no real advantages to using more than two coats.
The final part of Brainerd Jones' instructions were to apply a second coat of linseed oil, mixed 2:1 with turpentine, once the wood was in place. This is an old formula for furniture polish that may date back to the 18th century; variations appear in many Victorian texts, sometimes using a 2:1:1 mix of linseed oil with turpentine and vinegar, the latter as a cleaning agent.
Below is a photo of the sample wood with a 2:1 mixture rubbed the entire width, with no effort made to restrict the application to the sample strips.
The turpentine/linseed oil formula makes a dramatic change. Much more red is immediately
apparent, as shown in this closeup of the section with 2 coats of linseed oil.
The color is also far more uniform, split between just the two shades of deep red and dark brown. The lighter brown tones seen in all the oil-only tests are gone.
While this 2-coat oil/turpentine test results in a slightly darker color than the single coat of linseed oil specified by the architect, it makes up for it in the dramatic boost in red tones. Overall, we believe this must be what the exterior wood would have looked like if it'd been kept in original condition since 1905.
Jones was emphatic in the contract specifications that there should be no paint used on exterior wood. Although he capitalizes words sometimes, he only underlines on two occasions, both to specify NO PAINT (pages 9, 11). Today, almost all of the outside wood is painted a flat brown -- although the two doors on the front porch retain their original finish.
The specifications are clear that "all exterior wood work will have oil finish," which should be "one good coat of Pure Boiled Linseed Oil" before the wood is in place, and then a second coat of linseed oil, mixed 2:1 with turpentine (pg. 18) when the carpentry was done.
Our restoration will strip the paint and restore the oil finish.