×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Reusing Existing Wood Members

Reusing Existing Wood Members

Reusing Existing Wood Members

(OP)
I am currently working on a project where the owner wants to reuse some existing wood rafters, posts and beams for a new project. The wood was taken from an old (about 80 to 100 years) barn. The wood would be used for a porch overhang around the perimeter of the new building. I am in Florida so the wind loads can get pretty high. They are going to get the wood re-planed, so the new dimensions will probably be dressed sizes. I was going to ask the owner to send me a sample, so I could take a look at it even though I have no idea how to deduce anything by looking at it.

I don't know the species or anything else. What would be some way of assessing the structural properties of this material? Are there any code guidelines for unknown species?

Thanks

RE: Reusing Existing Wood Members

There have been strings on this in the forums in the past. You might want to do a search here.

Mike McCann
MMC Engineering
http://mmcengineering.tripod.com

RE: Reusing Existing Wood Members

If you know what the sizes are to be and how the old lumber is to be used. You can calculate what the required values that will be needed. If the required values are less then the minimum values in the NDS Supplement you are probably okay.
If they are not, have the owner measure the sg of the lumber. You can do this by checking the moisture content, weighting and measuring the volume of each member. Take the lowest sg that you get and compare your require values to the values of lumbers in the NDS Supplement that match that sg. You may want to apply a personal safety factor to this calculated sg.

Garth Dreger PE - AZ Phoenix area
As EOR's we should take the responsibility to design our structures to support the components we allow in our design per that industry standards.

RE: Reusing Existing Wood Members

Maybe a testing lab to determine allowable stresses.

RE: Reusing Existing Wood Members

Hello,
Is there any way of estimating the loads the members carried previously?

Geoff

RE: Reusing Existing Wood Members

100 year old bard wood from FL, will be old growth Cypress or heart SYP. Visual observations will tell you real quickly what one it is.

RE: Reusing Existing Wood Members

(OP)
The barn is not from Florida it is from the Midwest somewhere, I think Ohio, the owner is bringing the lumber down to Florida to re-use

RE: Reusing Existing Wood Members

Look at it. See what you think. You might be able to find a local visual grader (licensed or experienced).

I have often used an Fb in the 1,000 psi range with a good Safety Factor - so that you might really only be using about 700-800 psi - about as low as any visual lumber goes.

Also, look at its use - just a porch?? Who cares if it fails unless you are sitting underneath it.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources