Mystery Marks on the Walls

Ghost in the Walls

Look at the forms and you can see ghostly regular shapes! What are they? These appeared the day after our recent concrete pour. Any ideas on what caused this? Another physics problem…

More Ghosts in the Walls

Ben discovered the ghosts and pointed them out to me this morning. He had figured out what they were. I’ll give the answer after people have had a chance to think about it and leave ideas in comments. Don’t be shy!

One very interesting thing was that on Monday night after the pour had solidified we started pulling the threaded tensor rods. The interior up the Abattoir and Admin were hot! It was 80 or 90 degrees F in there! All the ice that had been in those rooms from when they were exposed melted. This was the heat from when concrete sets in an exothermic reaction which gives off a lot of heat. The building was insulated on the exterior to contain the heat which helps it set faster and stronger. But inside Admin/Abattoir there was no insulation so the heat went in there. You could touch the walls and they felt hot.

Now on Friday, four days later, the walls are still hot and the building is still warm although not quite as steamy. This raises the interesting thought that you could heat an entire building by the heat from the chemical reaction of cement setting up if you’re willing to pour enough concrete… Oo-la!

On the flip side, the coolth attic of the reefer was very cold. That is where the interior is completely isolated from the hot concrete by 16″ of Formula 250 pink foam insulation for a total of R-80 insulation – The reefer runs around R-100 depending on the section. The result is the heat of reaction was completely kept out of the reefer and it was still very cold in there. This made for quite the contrast from the hot section of the building and demonstrated that all my careful insulation has worked.

Outdoors: 36°F/28°F Cloudy, 1/2″ Snow
Tiny Cottage: 67°F/64°F

Daily Spark: ZenGeek to ZenMaster: “Oh, no, I don’t have to meditate, I have an App for that!”

About Walter Jeffries

Tinker, Tailor...
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9 Responses to Mystery Marks on the Walls

  1. eggyknap says:

    It seems it’s moisture from the concrete on the other side, or alternatively, from somewhere else in the “steamy” interior. I can’t explain the shapes; I was guessing it’s some detail of the construction I don’t know about (or rather, missed when you blogged about it earlier sometime).

  2. Kylee Anne says:

    The marks look wet but the surrounding wood looks dry. Does that have something to do with the the heat of the cement?

  3. John Klimes says:

    I am guessing that it is windows and since there is no concrete behing them the are not drying.

    • Perfect! You hit the nail on the head. The hot concrete dried out the plywood where it was in contact but in the window areas there was just air behind the form plywood so that stayed colder and water from the room air condensed in those areas soaking and darkening the plywood where the windows are. Our abattoir will have large windows up high to let in lots of natural light. This will make it more pleasant to work, give good lighting to judge meat quality and save electricity.

  4. JohnL says:

    Following progress with huge interest, Walter. How are finances holding up? John L

    • I think we’ll have just enough to get cutting and sausage making finished. Then what we save on doing that ourselves will hopefully fund the next phase and so on to finish off the facility. We are still doing CSA Pre-Buys and such so if you’re interested or know of anyone who might be, please spread the word. They’re a great deal.

  5. Daniel says:

    I didn’t get to this soon enough to sound original, but windows is what I had in mind before I got to the comments section.

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