Reinforcing Door Stiles with Steel

      Is steel reinforcement a practical idea to prevent a wood door from warping? Here's a discussion. August 22, 2014

We've been asked to make a mahogany slab door for a client. The design calls for a tall, narrow glass detail set about 6" from the lock edge and 6" from top and bottom. I would be making a ladder core with 1/4" skins on all faces and edges. I am concerned about stability on the lock side. I'll ask for a redesign to allow for larger top and bottom rails but am wondering whether a piece of steel running top to bottom inside the door would prevent bowing. Has anyone used this method?

Forum Responses
(Architectural Woodworking Forum)
From Contributor O:
I laid steel into the edge of one paired door set-up once. It was a lot of work, and I have never done it since. Those doors were thin, and I thought I was supposed to do whatever the customer wanted. The stile can get its strength from increasing thickness. I will not warrant an exterior door at 8' or over unless it is 2-1/4" thick, and 3" at 10' or over. How thick are you planning? The 1/4" skins sound thin - what happens when they move?

From the original questioner:
The door is 2 1/4", so basically a 1 3/4" stave core type construction with the 1/4" on the outside.

From Contributor O:
I assume the construction method you plan is familiar and has been successful for you in the past. It sounds as if you are building a stile and rail door, with stave cores faced with 1/4". That all sounds fine. You should have no flimsiness with 2-1/4" thickness unless it is extraordinarily tall. There is nothing unusual about a 6" stile and 6" top and bottom rails. Just use some nice long tenons, and cope and stick if possible. It is okay to trust wood. From your use of the word slab I assumed a flush type door. In our area slab means flush door, and door only, no frame, etc.

From contributor R:
Interior or exterior door? Wood moves, steel doesn't. Well steel does move, but very, very little. Steel rusts, wood doesn't rust but it rots. So trap moisture between the steel and the wood on an exterior door, and you get rust stains first, then rot. I wouldn't do it.

From contributor A:
If you are hell bent on reinforcing the door I would rip the stile in half and glue it back together with a 1/4" x 13/4" pultruded carbon fiber flat in the middle. Then bury it under the thick veneers. The stiffness would be off the charts. Yes, you can mix carbon with wood. It is done all the time. The cost of carbon strip and tube has come done quickly. The cost of the carbon should be easily offset by the minimal labor compared to other methods. Carbon is used extensively to reinforce wood masts, booms, kayaks, and other watercraft. In my opinion Contributor O is correct in saying that you should be fine with the 2 1/4" style.

From contributor W:
Iíve built plenty of exterior doors and Iíve always used a triple lamination for my stile and rails and Iíve never had warpage. If you want you can allow for deep "3/4 width of stile" tenons using the center lamination as the tenon/mortice. I guess you could use the 1/4" skins but Iíd still laminate the core.

From Gene Wengert, forum technical advisor:
A steel rod is used in large windows to prevent warping, which would potentially break the glass. It is easy, but does add weight. It works well indeed, so I suspect it will work well a door.

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: Architectural Millwork

  • KnowledgeBase: Architectural Millwork: Doors and Windows

    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 © 1996-2020 - 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