1990s Microllam Properties

[Craig_H]

Hi Folks,

I've got a residential renovation project that I am kicking off here, and the original building drawings (from 1997) seem to call out Microllam LVL beams. Having been in elementary school at that point in time, I don't have much personal context for the engineered wood product market back then. I do know that Microllam was the original LVL product, and I am guessing that they likely had one grade of the stuff, hence why the drawings just call it out as "1-3/4" x 11-7/8" M.L.".

The only resource that I could find online is this from Weyerhaeuser, dated 1988: Link. The document title is "TJI 25, 35 & Microllam LVL - 1988.pdf" The properties for Microllam from that document are below (for context, roughly 50% of strength values for a top end modern LVL):

I am currently limiting my work to a feasibility study to assess whether the client's desired renovation is doable without unreasonable demolition and reconstruction. Is it safe to say that the Microllam properties in the mid-90s would have been similar to the 1988 brochure, or were there significant changes/innovations/new-product-offerings that occurred between those dates? I'm hoping that if this goes forward, and we open up the walls, that we might be able to glean a bit of additional info from whatever markings are on the beams themselves.

Thanks all in advance for any historical context and information!

 

[kipfoot]

There were no great leaps forward for the material; it's essentially the same. Current values are a bit lower than those in the table you show from 1988.

 

[Craig_H]

Thanks, kipfoot! I realized after posting that these '88 design values are ASD, and I was comparing to LRFD values from current brochures. Interesting that nothing much has changed on that product line, I'm used to tip-toeing into existing materials, fully expecting to find the ghosts of generations past.