Glulam vs Parallam Beam
Glulam vs Parallam Beam
(OP)
I'm looking at both products and would like to determine whether I specify proprietary product or go to a performance spec. and give sizes and grades. My end result will be the same it’s just that I don't want an RFI form the contractor during construction asking me to switch out one for another. Does anyone have any thoughts or experiences with this issue?
TIA
TIA






RE: Glulam vs Parallam Beam
RE: Glulam vs Parallam Beam
RE: Glulam vs Parallam Beam
RE: Glulam vs Parallam Beam
RE: Glulam vs Parallam Beam
My design philosophy is to specify the best product for the design application. Parallam has high design values which work well for applications that require small highly loaded sections. So I recommend using it where you need it and not specifying it for all beam and column applications on a project.
It appears that a lot of engineers if they have a need for Parallam on part of the project they will specify it every where. As a structural engineer I can understand why that approach is appealing. You only have to deal with one set of design values and will be able to minimize the depth and width of your sections.
Also it may reduce your time later. If some one submits a substitution request, you just mark it rejected and instruct the contractor to provide what was specified on the drawing.
If you are going to take the above approach however you should know what the limitation of Parallam are. I work in Minnesota and would question the statement that Parrallam is more readly available than glulam. I am not aware of any local lumber yards in this area who stock Parallam. Like glulam they are order from wholesalers. Common glulam sizes are ordered from wholesalers not from the plant.
Also one must keep in mind that Parallam is not produced in curved shapes or with camber. While treated Parallam is available it is a specialty product. Treated glulam is available in a wide range of sizes from any stocking glulam wholesaler,
RE: Glulam vs Parallam Beam
RE: Glulam vs Parallam Beam
A Parallam, manufacturered by a well known company, is what the NDS call parallel strand lumber (PSL). Right? Who else makes PSL members? I cannot find any when I search the internet. Looks like the mfr is keeping up with anual donations to the American Wood Council.
h
RE: Glulam vs Parallam Beam
RE: Glulam vs Parallam Beam
RE: Glulam vs Parallam Beam
As far as avoiding RFI's go, Your best bet would be to figure out what the contractor wants and spec it. Past that, you can make them EASIER by spec'ing GLB's, and then most all SCL will have superior values (providing the camber and moisture differences are a non issue as pointed out above), or use minimum values of SCL so most anything will work.
You can put the design values used in the plans and leave the product selection up to the contractor, but I wouldn't recommend it, since they may not know/understand all the implications of what they're looking at.
RE: Glulam vs Parallam Beam
More often than not, GC gives plans to their lumber yard/supplier, who cross ref.s members to whatever they carry (GP, Boise, whomever)
RE: Glulam vs Parallam Beam
RE: Glulam vs Parallam Beam
RE: Glulam vs Parallam Beam
I have not used or specified Parallam or LSL materials as they are not as readily available, according to the contractor's and suppliers I've worked with. If the beam is to be exposed, I will specify a glulam. If an LVL will not work, I use steel.