What Is A Microllam?
Microllam / LVL Beams
Recently a reader asked: “What Exactly Is A Microllam”? It’s understandable that there could be confusion because the industry is full of all kinds of engineered lumber today. In this article I’d like to point out what a Microllam or LVL beam is.
Laminated veneer lumber (LVL) is an engineered wood product that uses multiple layers of thin wood assembled with adhesives. It offers several advantages over typical milled lumber: it is stronger, straighter, and more uniform. It is much less likely than conventional lumber to warp, twist, bow, or shrink due to its composite nature. Made in a factory under controlled specifications, LVL products allow users to reduce the onsite labor. They are typically used for headers, beams, rimboard, and edge-forming material. – Ref: Wikipedia
Microllam is a brand name for Laminated Veneer Lumber (LVL) Beams manufactured by Weyerhaeuser. LVL beams are one of several different types of engineered lumber products on the market today.
What Microllam’s (LVL’s) Look Like
The photo above shows a Microllam LVL header over a door in a basement. The header was built using three (3) 9-1/2 inch deep Microllams that were nailed together. The first clue that this is a LVL header is the appearance. Most LVL’s on the market have a smooth face that looks like plywood.
The adjacent photo shows the bottom side of the Microllam / LVL header beam. The second clue to idendifying the LVL is the long, straight layers of the beams. LVL beams always have straight, parallel layers which is very different than similar Parallel Strand Lumber (PSL) beams which have lots of shorter fibers that are compressed.
The last clue that you’re dealing with a Microllam / LVL beam is the width. LVL’s come in 1-3/4 inch wide beams always. Whereas PSL beams come in many width from 1-3/4 inch up to 9 inches wide (0r wider). The last photo shows a PSL beam, which shows the shorter strands/fibers.
Can I use Glulam for collar ties in my attic for roof rafter? I want to remove all existing rafter ties in my attic. I have 12 rafters with 5 having collar cross ties (on 1/3 from the top) at every other rafter and other 5 (alternate rafters) having rafter ties on alternate rafter. I want to be able to get rid of all the rafter ties as they are in my way of the function use of my attic. Existing ridge beam length is 2’X6’X26’ and the height of my attic is 8’ at the ridge I also have five 2X4 rafter ties across my attic that prevents me from getting around.
The problem is if you don’t have a structural ridge beam, with proper connection to the rafters, you can’t remove the collar ties. Without seeing it in person I can’t tell for sure, but you really do need an engineer to evaluate.
I am spending 16 foot to hold the second floor up I am taking a wall down on the first floor to make it opened how big a beam do I need
Larry – You need to use the design tables. I can’t do that for you as it’s a liability issue. If you need help, most lumber yards will help size the beam.
Hi, I am looking at building a two story great room and would like to build the perpindicular walls that the rafter tails sit on. I would like to build 2nd floor walls to be 85 7/8 and put a 3 1/2 x 12″ psl on top of walls and put aplumb cut on heel cut to nail into psl with teco hangers,this way the wall hieght would be total of 97 1/8. This way I can keep the rest of the 2nd story walls at 8 feet. Is this feasible.
Without seeing a sketch I’m not certain. Are you thinking building a two story wall in two sections? I’m confused.
If contractor was to install 3-1/2×9-1/2 ml but instead used 3-2×12 pt sandwiched together would it be much difference in your opinion?
Possibly….should be reviewed for actual capacity
I am looking to build a 30×40 2 story basketball court with an overlook. I was told that it would not be possible to heat & cool the overlook area (approximate 1500 sq. ft. of living space) with the open area and I must have that enclosed with tempered glass.. Do you have any suggestions as to how to keep it open without adding glass and still able to heat/cool the court and the overlook area. I will have zoned heating/cooling and a separate furnace/ac for each space.
Donna – It’s hard to say without seeing a plan. We build a large squash court with an over look for a client and it has an open viewing balcony on the 2nd floor. We used forced heat/ac and it’s not horrible.
How would it weather if used for a planter?
Not well :)
What are the actually structual load differences between lvl and psl beams of same demensions? Its always a struggle when the engineer doesnt give options on plans for exact replacement for psl vs lvl. Sometimes it isnt efficient or safe to install psl beams
They are quite different. You’d have to look up the tables and compare carefully, this is typically best left to a professional engineer.
My builder w/ his lumber supplier rotated ceiling joists 90 degrees from architect design. Arch design had a 16″ LVL beam over an outside wall for support over a window wall. LVL was left out and a traditional 2×4 top plate was erected with the (now turned 90 degree) ceiling joists resting on it. The window wall is 8’tall x 12′ wide. Total original span for LVL was 22′ with traditional studs and rough out for window wall as support. I believe there is approx 9″ between bottom of top plate and upper demension for window wall rough out. I guess my crude question is can the LVL be ripped down to approx 9″ and double or even tripled (width) and get the same performance from the single width 16″LVL. I realize his may be an impossible question to answer. Right now I’m scrambling to prepare my debate with this guy. I know he prepping to discuss eliminating the window wall in lieu of windows.
Thank you for your time,
There are 9-1/4″ LVLs and load tables for them. I’m certain they could design one that depth, whether it’s single, double, or triple to get the capacity.
I am finishing my basement and want to keep my microlam beam exposed. I would appreciate any suggestions on options to finish it. It currently looks exactly like the first photo in the article, (door header) but mine is 22’ long.
You could paint it.