Drying Lumber in the Attic

      It's hot and dry up there maybe too dry. But for small amounts, attic drying is feasible, though tricky. December 1, 2005

Question
I'm considering using my attic as a kiln for drying some 5/4 green walnut. It gets very hot up there (120+ deg.) and I live in a pretty dry climate at 7,000 ft elevation. Should I air dry some first? Should I set up a fan to blow over it? I'll end coat, of course, but I'm worried it'll dry too fast.

Forum Responses
(Sawing and Drying Forum)
From Gene Wengert, forum technical advisor:
I would also be worried, not because of the heat (which is typically about 40 F hotter than outside), but because of the very low RH.



From contributor D:
I've attic dried a few (small) loads here in OK. The key is to air dry the lumber to or below 20% MC first. Then sticker the lumber in the attic as you would outdoors. I never ran a fan over the lumber intentionally. We did run the indoor attic fan some. Dried white oak, 1-1/8" lumber, 20%. Attic drying is some work, but what ain't? Just don't overload!


From the original questioner:
Gene, what do you think about air drying first? Or could I humidify the attic somehow? What's the ideal RH?


From Gene Wengert, forum technical advisor:
You should air dry first. Humidifying the attic is not a good idea at all.


From contributor R:
Here's my experience with attic air drying. Instead of bringing the lumber to the heat, I set up a box and with fans and hoses, sucked the attic air to the lumber. Here is how it works successfully for me:

a. Lumber is air dried first.
b. Sticker lumber on hard surface (ground floor or 2nd floor of shop).
c. OSB sheathing makes for a cheap container - build around lumber to be dried.
d. Cut out holes for hoses (4" flex drains work) and install from lumber to peak of attic. Hoses equal number of fans, fans have been window insert type from Walmart-2 speed.
e. Hoses installed at top rear, fans located at bottom front, heated air simply collects moisture and passes through stack.
f. I hooked up a timer to the power of the fans. Set it to start at 10am and shut off at 8pm. Time can vary for a host of reasons.
g. Remember the moisture - it will stick to anything - insulation, sheetrock, etc. Make sure it gets out of harm's way.



Would you like to add information to this article?
Interested in writing or submitting an article?
Have a question about this article?


Have you reviewed the related Knowledge Base areas below?
  • KnowledgeBase: Knowledge Base

  • KnowledgeBase: Primary Processing

  • KnowledgeBase: Primary Processing: Air Drying Lumber

  • KnowledgeBase: Primary Processing: Kiln Operation


    Would you like to add information to this article? ... Click Here

    If you have a question regarding a Knowledge Base article, your best chance at uncovering an answer is to search the entire Knowledge Base for related articles or to post your question at the appropriate WOODWEB Forum. Before posting your message, be sure to
    review our Forum Guidelines.

    Questions entered in the Knowledge Base Article comment form will not generate responses! A list of WOODWEB Forums can be found at WOODWEB's Site Map.

    When you post your question at the Forum, be sure to include references to the Knowledge Base article that inspired your question. The more information you provide with your question, the better your chances are of receiving responses.

    Return to beginning of article.



    Refer a Friend || Read This Important Information || Site Map || Privacy Policy || Site User Agreement

    Letters, questions or comments? E-Mail us and let us know what you think. Be sure to review our Frequently Asked Questions page.

    Contact us to discuss advertising or to report problems with this site.

    To report a problem, send an e-mail to our Webmaster

    Copyright © 1996-2016 - WOODWEB ® Inc.
    All rights reserved. No part of this publication may be reproduced in any manner without permission of the Editor.
    Review WOODWEB's Copyright Policy.

    The editors, writers, and staff at WOODWEB try to promote safe practices. What is safe for one woodworker under certain conditions may not be safe for others in different circumstances. Readers should undertake the use of materials and methods discussed at WOODWEB after considerate evaluation, and at their own risk.

    WOODWEB, Inc.
    335 Bedell Road
    Montrose, PA 18801

    Contact WOODWEB











  • WOODWEB - the leading resource for professional woodworkers


      Home » Knowledge Base » Knowledge Base Article