Specification for the reuse on wood framing onsite

[rscassar]

How are people specifying the use of recycled wood for structural purposes?

I have a situation where a contractor wants to reuse wood trusses which they have pulled down from elsewhere on the project in-lieu of framing which has been specified on construction documents.

Generally I request the builder to submit evidence that the wood which turns up onsite complies with the standard set-out in the specification and likewise for moisture content and preservation treatment. How would this be achieved if the wood is reused? What must be performed to ensure that this wood is up to standard?

 

[MiketheEngineer]

If these are basically "new" trusses and meet all the loading requirements - why not??

Make sure that any bearing areas have not been torn up by nails or clips or rework the attachment some way.

 

[Ron]

Removing and moving trusses can be done; however, they should be carefully inspected for damage and truss plate contact. I would recommend nailing the truss plates

 

[MiketheEngineer]

I would definitely inspect the truss plates to make sure there is no corrosion and that they are still well embedded. But just nailing them for no real good reason could do more damage than it helps. If they have pulled out - I would probably reject them.

 

[rscassar]

Thanks for the replies. I have told the contractor I did not want to accept the existing roof trusses because we have no documentation to say what stress grade the wood is, likewise do not know the preservation treatment.

What can I do to determine the stress grade and moisture content on-site. Do I need to perform a proof test to establish the load carrying capacity or are there other means for establishing the stress grade on-site?

 

[MiketheEngineer]

The lumber should have a grade stamp. The truss mfg should have a drawing indicating all capacities and lumber sizes and grades that were supposed to be used. Also any mention of preservation treatment should be shown on the lumber. If in the US - I doubt it was treated - unless it was a very special application.

As for mositure - you will have to buy, rent or steal a meter.

If none of the above can be readily identified - I would be reluctant to re-use.

 

[Ron]

Mike...the reason for nailing is to maintain contact from too much movement/handling. The capacity of nailplates goes down tremendously with decreased embedment. Using small nails to maintain integral contact is a necessity.

 

[rscassar]

Thanks for the help guys. I have told the builder that I require evidence of all three items before I am willing ro accept the trusses along with my own visual inspection. In some sense, I am hoping that the do test for stress grade onsite because I am interested to see what the report is like.

 

[csd72]

I would suggest that they contact the truss manufacturer (if known) and get them to inspect the truuses regarding suitability for re-use.

Dont waste your companies money just to save some of theirs.