Rethinking Faux Teak Temperatures

Posted by Darrell Nicholson at 12:31PM - Comments: (3)

The touch test (30 seconds per sample x 3) provided more relevant information regarding the relative temperatures of faux teak decking. But at the higher ambient temperatures (surface temperatures over 160 degrees F) it was difficult to sense how quickly each deck cooled during the touch test.

Our recent report on synthetic-teak decking options (see PS December 2015) raised a bit of a ruckus among the contenders in what is an extremely competitive market. The main bone of contention was our reported temperatures of the various materials after they were left in the sun. Several manufacturers contended that the temperatures we listed in the table accompanying the article were not consistent with their own findings.

Readers familiar with the report will remember that we tested the temperature of these faux teak surfaces in two ways. First, we had three testers feel each surface with their hands, keeping it on each surface for 30 seconds. The samples were blindly paired against each other, round-robin style, and then ranked. The second way we checked temperature was by recording the surface temperature with a Fluke infrared thermometer; these readings were the temperatures listed in the article’s accompanying table.

The manufacturers’ complaints prompted us to repeat the test several times, record the data again, and then tally the re-testing results. After multiple rounds of re-testing, two things became clear, and although these observations were stated in the article, they did not get the emphasis they deserve, which led to some of the confusion.

First, the surface temperature reading is just that, a temperature reading the thin layer of matter at the top of the synthetic decking. It does not reflect the conductivity of the material, or how hot it is on the underside, where it meets the boat’s deck, or even how hot it “feels” to stand on for a period of time. Thus, surface temperatures from an IR thermometer can be misleading.

The clearest example of this is the Marine Deck, which is made with cork, the best insulator of all the materials we tested. The Marine Deck often showed a slightly higher surface temperature than some of the lighter-colored, plastic-based decks that were not nearly as effective insulators. Clearly, the surface readings we recorded were closely tied to color more than anything else.

The second observation was that in the subjective touch test, the duration of the “hot” feeling is important. Again, we refer to the Marine Deck. In the initial round of testing, cork deck also was indeed hotter to touch than some of the lighter-colored plastics—at first. However, once the hand or the foot absorbed the heat at the surface, the material immediately became noticeably cooler. This change was not so apparent to the testers during the first test, which was a particularly hot day (94 degrees ambient temperature, with surface temperatures exceeding 160 degrees). Only in the second round of testing (in 84-degree ambient temperatures, with surface temperatures above 125 degrees) did we notice this effect.

As a result of our follow-up testing, we have removed the temperature readings from the article’s table online, as we feel they may be misleading.

Our advice regarding temperature is common sense. If a cooler deck is what you want, go for the lightest color you can tolerate. The other factor to consider is density. The least dense materials will usually be cooler and will be a better insulator. Both the Dek-King and Flexiteek offer 2G materials that are less dense and lighter than their previous versions. These clearly cooled down faster during the touch test than the denser materials we compared them too, and they deserve a Recommended rating; the online report has been adjusted to reflect that. These deck materials are currently undergoing long-term testing, so we will have more to report in about a year.

Comments (3)

1) RE: the touch test. It's subjective but it may actually be the more important consideration. Even with materials of the same temperature, heat capacity of the material and the ability to transfer that energy is going to make it feel "hotter." For example, compare a 125degreeF sidewalk with a bath mat at the same temperature, and in bare feet we'd all pretty much prefer to stand on the bath mat.

2) Non-contact IR thermometers can have errors associated with varying emissivity of the materials under test. Metals have very low emissivity and plastics and rubber are very high. Some thermometers have a capability to set the emissivity factor and reduce error.

One way to see if there is an error is to take the material to a *known* temperature and then compare the reading. Or you can spray everything flat black and be sure you have an accurate, if possibly useless, measurement.

Regards,

Matt

Posted by: memobug | January 6, 2016 11:51 AM    Report this comment

I had a CAL T/2 that had slightly grey non skid on parts of the deck. I was always amazed at how hot it got and how walking on it barefoot was something I avoided.

Posted by: Bill F | January 6, 2016 11:51 AM    Report this comment

The difference between initial heat that is sensed, vs heat that has "soaked" into the material is indeed substantial, and a valid point to address. While color certainly plays a huge role, material is part of the equation as well. The MarineDeck cork product you tested is made of fine granule cork with lots of resin (maybe a petroleum product), so the composition isn't that much different, in terms of heat conductivity, than the pvc products. We have SeaCork on our transom steps, which is mostly cork and not much resin, and I'm constantly amazed at how cool it stays even in direct San Diego sun. I've measured it in the middle of a sunny day at only about 20 degrees warmer than the white gelcoat that surrounds it. Always comfortable with bare feet. It was one of the main reasons we went with cork in the first place. I'm just not sure that MarineDeck really represents the benefits of cork that well.

Posted by: Randy | January 6, 2016 11:31 AM    Report this comment

New to Practical Sailor?
Register for Free!

Already Registered?
Log In