Finding beams on wood roofs

[Baggi]

Hi, I am seeking advice from anyone with experience in large residential, flat wooden roofs. I want to map out the support beam structure under flat roofs without having to rip open the roofing. Pic below. Most old buildings in NY City don't have any blueprints. I'm looking for something better than the wooden mallet technique to locate the load bearing beams. Any reliable stud finders or other techniques you'd recommend? Thanks.

Note: This is for ballast mounting solar project. I'm in the process of gathering all data to be reviewed by a structural PE consultant.

 

[msquared48]

Well, I can read a couple of major beam lines from the photos. A site visit could tell much more from the deflection pattern of the roof.


Mike McCann, PE, SE (WA)

 

[Baggi]

Interesting, thanks. Taking the liberty to add a few photos of the above sample roof.

Northern section of the roof:

Southern section of the roof:

 

[JAE]

Thermal imaging cameras might pick up the beams. Depends on the thickness of the roofing. Might be better from underneath.

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[SLTA]

Go in through the bottom. That's really the best thing to do. The structural will likely insist on seeing the actual wood anyway.

Please remember: we're not all guys!

 

[Baggi]

Thanks JAE and SLTA. Agree, opening up the dry wall ceiling is probably easier than the roof.

Would still appreciate any product recommendation for a thermal imaging camera and stud-finder that worked well for you. Thanks!