Glulam Building: Start to Finish – Part Nine D

 Welcome to our “Glulam Building: Start to Finish” series. Our goal is to provide an overview – from idea to completion – of a glulam building, from the perspective of the glulam manufacturer and designer.

Part 9D: Fabrication Details

Overall profile cuts and holes are the most apparent part of glulam manufacturing, and those are the items we included in the 3D computer model of the project. But, there is another lay of fabrication – the specifics of which are mostly determined right in the finishing department – that can make all of the difference in the assembly and aesthetics of the finished product. This includes: edge routs, plugging, and easing for welds.

Areas circled where edge routs stop for beams to fit flush

Edge routs are simply rounding over the finished edges of glulam members. This serves both a safety/handling purpose and an aesthetic one. Finished glulam parts are heavy – sometimes several tons each – and are typically lifted using nylon slings. Square corners are more likely to be crushed by (or cause damage to) the slings. Square corners can also be dangerous to hands, causing cuts or splinters to workers – or to the general public if square corners are in accessible areas. The tricky part is knowing where to stop and start the edge routs. When two members come together with matching width or depth (like members of a truss, or two equal depth beams coming together), the project will look much more “finished” if the edge routs stop where the members meet.

Routs in a Doug Fir beam for square plugs

Sometimes it is necessary to fill voids on the sides of glulam members. This can happen at open edge knots, or at “low plies” (where plies are slightly mis-aligned and one might not get  finished when going through our large planer). While it is technically allowed to fill many of these with a hot-melt plastic filler, that looks far from great. We take the time to repair these with solid wood plugs – rout out the defect, cut a plug to match the size, glue the plug into place, then hand plane it flush. Using a square cornered plug aligned with ply lines – it can end up virtually invisible. Plugs can get extra tricky when required in curved members or combination layups.

“Ease for Welds” is a common phrase you’ll see on our shop drawings. As mentioned in our Steel Fabrication segment, almost all of our steel assemblies use fillet welds throughout – so a simple U shaped beam seat doesn’t have square corners on the inside, those corners are filled with weld. For glulam members to fit in the seat the corners need to be chamfered. The exact length and locations of these Ease for Welds chamfers are determined in the shop – so our Finishing Department needs an excellent understanding of reading both glulam and steel shop drawings. 

Bottom of columns shaped for base connection to fit flush with eases on the edges to accommodate fillet welds

Columns with base connection attached