span table for old ACTUAL dimension floor joists?
span table for old ACTUAL dimension floor joists?
(OP)
Has anyone ever seen a span table for old ACTUAL dimension floor joists? Ie for 2X4 which are actually 2x4, not nominal 1.5 x 3.5. I realize that without a structural stamp, its hard to tell the exact attributes of such wood. Still, an actual dimension lumber span table would be a useful starting place.






RE: span table for old ACTUAL dimension floor joists?
RE: span table for old ACTUAL dimension floor joists?
Mike McCann
MMC Engineering
RE: span table for old ACTUAL dimension floor joists?
Crackerjack pretty well sums it up for me. Since you can’t buy it, without getting a small mill to specially cut and dry it for you; and since you then have to have it graded, if you are going to sue it for anything serious; I think a table for a bunch of different grades and sizes would not get much use. On the rare occasion that you do run into this situation, you calc. the section props. based on what you’ve measured; then you take an educated and experienced guess at the species and the grade and go from there. You can have a good wood lab determine the species, and a grader come in and make some grading judgements on site, if needs be.
RE: span table for old ACTUAL dimension floor joists?
RE: span table for old ACTUAL dimension floor joists?
BA
RE: span table for old ACTUAL dimension floor joists?
I'd like to learn how to identify species and grade, in lieu of grade stamp, that is. Any pointers/references on this would be welcomed.
thanks in advance
RE: span table for old ACTUAL dimension floor joists?
Mike McCann
MMC Engineering
RE: span table for old ACTUAL dimension floor joists?
RE: span table for old ACTUAL dimension floor joists?
As for "...how to identify species and grade, in lieu of grade stamp..." a grading book from WWPA or other grading association will have information on what is required for each grade of lumber. The species?
But I do think you can get graded rough sawn lumber or are you looking at reusing lumber?
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: span table for old ACTUAL dimension floor joists?
RE: span table for old ACTUAL dimension floor joists?
Write your own spread sheet to do the required calcs. as a function of field measure sizes and spans and assumed species and grade. As suggested you can study the grading rules over the years, there are classes for becoming a lumber grader, which you could take. Hundred year old houses might have been made of any good local wood, ask some old contractors, restoration people, old lumber guys, not the kid at the bog-box. To do what you are talking about the right way, you have to do an inspection of the/each roof system and measure sizes and spans. Probably, more importantly, look at the entire roof and all the important details for condition or defects and deficiencies. Is the roof sway-backed from years of permanent set and deflection, indicating too flexible a roof for the existing loads? Are the joints intact, not pulling apart, crushing or splitting, enough bearing area, properly cut and fitted, no rafter thrust problems at their bearings, etc. Now, you can start to make a current condition judgement, and start thinking about any excess rafter cap’y., or how to add some reinforcements, or how to distribute your new point loads to several rafters to meet your needs. With time you may gain some experience and efficiencies at doing the analysis and making the judgements about possible options, but I think you pretty much have to do the inspection, etc. to arrive at an educated and engineered sale. One size does not fit all, and one simple table will not do it for you either.
RE: span table for old ACTUAL dimension floor joists?
Mike McCann
MMC Engineering