Framing with Glulams

Interesting looking article, folks, but bear something in mind.  The main reason that many timber "lovers" turn back to more conventional construction methods is overall cost.  TF is expensive, both in terms of labor and the materials required...and, although engineered beams are plenty strong enough, they're even more expensive than milled natural timbers...and something tells me that they would require more labor to get the same results -- and both are things that keep prospective TF home owners awake at night.      

Even in timber frame country, where I live, it is sometimes difficult to get the "officials" to go along with something that they're not familiar with, Holmz.  I've even heard stories of well-established master timber framers who've had to build scale models to get a structural engineer, of all people, to go along with a given frame design.  That's why it always pays to find a structural engineer who's been there and done that when it comes to TF design.     

Yes but a lot of engineers may only specialise in metal and concrete. So may have limited experience. I know that if I was having this kind of work done I would make sure the engineer specialised in timber construction. When in my head I'm pretty confident it can work. The only problem with myself doing in my thoughts isn't going to pass as I don't have the letters to my name and I certainly can't remember how to do the calculations

Here's a ceiling my company framed a few years ago.

Firstly, who or what is or are TFs?

I've used engineered beams in my last 3 places. To me there's nothing easier. Over here, all engineered timber has an appropriate engineering standard in regard to stiffness and stress ratings. There's also published span tables available for just about each & every possible application. This is also true of most if not all engineered (manufactured) construction elements, be they solid timber, glulam, LVL, CLT or steels. I've personally only used the first 2 in my own constructions: I'm currently in the initial stages of designing a 3 storey dwelling with a "roof garden" in cross laminated panel construction.

Currently, my ambitions are unfortunately way ahead of the local industry's ability to supply the requisite materials. The closest CLT production plants are NZ (shitty P. radiata), Austria & Scandinavia, where I believe the raw materials are in (presumably Norway) Spruce, which is a far more resilient & "noble" timber. They (still) build airframes from spruce, whereas pine is in my opinion really best suited to paper production. Best of all would of course be Tas. Oak, but I think that mere wishful thinking. LVL & CLT production facilities would by necessity be predicated around the efficiencies of plantation production, with its uniform age and dimensional characteristics allowing highly efficient mechanised harvesting, conversion & lamination techniques and reliability of supply. This in Australia unfortunately means Pinus radiata, which is to my own rather jaded eyes little better than a weed.

We also have a rather substantial Eucalyptus nitens & globulus plantation estate, but as yet lack the ability to efficiently utilise this particular resource for anything other than paper production. Businesses have tried, and failed, conversion of larger stems into standard construction timber, due in the main to the harvested logs' propensity for substantial end checks from rapid growth stresses being released.

What I like most about glulam construction "timbers" is their relative light weight. Being so much stiffer than solid alternatives allows hardwood beams to be used in significantly smaller dimensions for the same load & span characteristics. This has been extremely important in my own 3 previous applications, where they've been used solely to support annealed glass "roofing" @ 1200mm centres & 6000mm spans: impossible in solid timber, with the only other (expensive) alternative being steel. They're also extremely useful in cantilevered applications, where precambered (bent or curved) glulam joists can be installed "upside down" to counteract sag in substantial continuous unsupported spans (with the cantilever up to 30% of the "fixed" span). As an added bonus, the smaller dimensions allow the beams themselves to effectively "disappear" visually, enhancing the lightweight nature of large span (especially glazed) unsupported roof construction. I also rather like the visual effect of these exposed lightweight timbers. For even smaller dimensional allowances, or correspondingly even greater span tolerance, some beams can be ordered with deformed bar reinforcing within the top & bottom pairs of laminations which substantially increases strength & stiffness.

This combination of stablity, expediency, measureability and repeatability makes for extremely straightforward and inexpensive design & construction. Unlike steel, a working knowledge of span tables will effectively negate the need for engineering approval in otherwise straightforward conventional dwelling construction. To date, construction engineers have been an expense that I've been able to avoid. Strict adherence to published standards have made the need for their engagement or involvement pretty well unnecessary.

From a green perspective, the ability to utilise shorter lengths of what would otherwise be waste material to construct significantly bigger & stronger solid construction timbers than would otherwise be possible is a win-win. More return for less timber wastage.

They'd be proper glulam beams I suppose.  Yet another super construction timber, which we see very little of here in the South Island. I've heard great things about the resilience & strength of the Jarrah, Karri & Marri "triumvurate" of structural timbers from the 'Souwestern corner.

What I was whinging about was the lack of hardwood in cross laminated panels. They're more like a timber version of precast concrete tilt panels and flooring slabs, in dimensions of about </=3000 mm widths & variable lengths (made to order) up to a possible max of 18000 mm+ and thicknesses (60-500 mm) being the odd-numbered multiples of their constituent board laminates. Seriously big "slabs" of timber that are used in a similar manner to any other type of precast concrete building element. But of course with the advantage of being one fifth the weight/unit volume and having the same malleability & workability characteristics (& flaws) of any other timber building material.

Even in crap pinewood, they're capable of unsupported floor load spans of up to 7500mm, which is pretty damn amazing by any stretch! This, coupled with the ease & rapidity of transport & installation with basic carpentry tools (i.e. no shuttering, concrete pumps or other wet trades) and much smaller & lighter cranes makes for a quantum leap in construction efficiency.

Just as with glulam & LVL beams, they're built up of multiple laminates, but as with conventional plywood (i.e. not LVL, which has parallel grained veneer elements) where each layer is @ right angles to its immediate neighbours. This in particular seems to be a sustainable, efficient alternative to "dirty" concrete, with the ability to create the structural wall & flooring elements in timber and steel high-rise buildings (currently only 10 stories max, but there's plans afoot for 40+ story residential developments) that can passively sequester carbon as a lightweight green alternative to the heavy, poorly insulated & extremely embodied-energy dense concrete alternative.