Bracing solid surface

      When using solid surface materials, what sort of "bridgework" is needed for support? June 24, 2001

I've seen 1/2" (and I think 1/4") solid surface used in place of 3/4 inch material. There was an underpinning "bridgework" under the surface. How do I figure out the bracing required to substitute thinner material?

Forum Responses
I cannot say about the other brands, but with Corian®, 1/2 inch has been the standard thickness for over 20 years. It only requires 20" on center "bridgework" or support within 10" of any point. 1/4" is never recommended for horizontal application, even if over a substrate (like MDF).

It is correct that 1/4" thick material is not suitable for horizontal applications. However, the minimum distance between supports in the "bridgework" for 1/2" material is 24". Technically, a 2' X 2' square or 4 square feet of Corian® will support itself in the field with proper perimeter support. By law, a ladder structure must be built using moisture resistant MDF or plywood. The strips should be between 3-4" wide and joined with biscuits, dowels or rabbited seams, screwed and glued. Also, the supports must travel the full width of the countertop (front to back) at all cutouts, i.e. sinks and cook tops.

The standard counter thickness for solid surface is 1/2", however the exact thickness does vary, so be sure to check it before fabrication. The bridge network described above is correct for 1/2" thick solid surface, however the spacing and allowable overhangs increase with the use of 3/4 material, although finding it could be a problem. SSV by Wilsonart is installed over a solid substrate such as particleboard or MDF, however a backer sheet must be used to balance the sheet. This may be where you saw solid backing. No SS manufacturer will warrant their product if installed over a solid surface such as a sheet of plywood, PB, or MDF. This is due to heat dissipation and expansion and contraction, the two major causes of failure (cracks).

It is correct that there are no solid surface manufacturers that will warrant a countertop with a solid substrate. The main reason is heat! Solid surface is not a good conductor of heat. If a heat source is applied to solid surface, it will not dissipate throughout the sheet, but must vent through the bottom. If the bottom is fully covered by a substrate, the resulting expansion from the heat will crack the surface. Lesser extremes of heat that may not crack the surface will whiten the contact area.

Expansion and contraction of the substrate is not as big of an issue. Using a moisture resistant substrate and balancing it can minimize the expansion rate to a point where it will not affect the solid surface. Certain manufacturers will give special consideration to using a solid substrate with 1/2" or 1/4" solid surface material. In applications such as an end table or cafe table, the product will not encounter a heat source. Original Equipment Manufacturers have been producing such products for several years now. But be careful if you do this, as there truly is no warranty. My point is that people are successfully using solid substrates in specific applications.

I cannot address other materials, but with Corian, part of its cost-effectiveness is that you do not need to make your product and then surface it.

1/2" Corian is strong enough to stand on when simply applied to a frame for an end table or coffee table. 3/4" has been out of vogue for such applications for over 15 years.

Out of vogue for sure, but still in the manuals and a special order, to say the least! There are some overhangs, such as bar tops and specialty furniture that may make use of this, although it sure does sound like something an architect would demand that you do! I had the same problem three or four years ago with 1/4" Corian. The local supplier quit stocking it due to the cost of breaking it in inventory, but it was still in the manual and the architect wanted it. Luckily, I did my research before signing the contract and declined to take the job (it had trouble written all over it).

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: Cabinetmaking

  • KnowledgeBase: Cabinetmaking: General

  • KnowledgeBase: Laminates & Solid Surfacing: Fabrication Techniques

  • KnowledgeBase: Knowledge Base

    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 © 1996-2019 - 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