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
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
Mike McCann
MMC Engineering
http://mmcengineering.tripod.com
RE: Reusing Existing Wood Members
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
RE: Reusing Existing Wood Members
Is there any way of estimating the loads the members carried previously?
Geoff
RE: Reusing Existing Wood Members
RE: Reusing Existing Wood Members
RE: Reusing Existing Wood Members
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.