You dream it, We build it.

At the heart of MacDonald-Miller is our 100,000 SF sheet metal, mechanical piping, and plumbing prefabrication shop. Our commitment to Lean Manufacturing and Pull Scheduling produce a high level of quality control, resulting in on-time delivery of superior quality products.

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Shop Capabilities

Sheet Metal Fabrication

We specialize in high-level modular prefabrication of equipment skids and mechanical piping racks. And our timing is pretty special as well – we’ve constructed entire mechanical rooms in our fabrication facility and then raised these modules in place onsite in as quickly as one day. Our response to every mechanical piping request is “yes we can do that” – because, well, we can.

Pipe Fitting Prefabrication

Our in-house piping shop is adept with several types of fabrication including welded pipe of virtually any size, fabricating multi-trade racks, frames for equipment, custom supports, stainless steel and more. To maximize our efficiency and quality, our 3D BIM/Detailing teams send “spool” packets of our complex piping systems which are then broken into modular sections that are built in our shop and sent to the site for a seamless installation.

Industrial Fabrication

With a level of expertise that qualifies our shop as a regional leader in highly technical metal fabrication, we efficiently assemble and deliver commercial and marine ductwork and fittings. This capability is in thanks to our outstanding sheet metal workers, many of whom are veteran fabricators with a wide range of experience.

Plumbing Prefabrication

In alignment with our LEAN values, MacDonald-Miller has invested heavily in our plumbing prefabrication capabilities enabling us to install a higher quality system in less time for your building. Our plumbing fabrication shop specializes in everything from multi-trade racks (MTR’s) to prefabricated risers to entire bathroom wall assemblies, and, we’re continually finding innovative ways to realize the benefits of off-site fabrication.

Product Delivery Ingenuity

We’ve designed, constructed, and certified a 5th Wheel Style Flatbed Trailer System that can be picked up and held by a tower crane. It allows us to pick up our material directly from the street just minutes after our delivery trucks arrive onsite. This trailer then acts as a stationary outrigger allowing us to unload our materials to any open deck – eliminating the restrictions of a permanent outrigger. This innovative solution will completely redefine the high-rise construction material handling and productivity process.

MacDuct Online

As a leader in highly technical metal prefabrication, we are able to efficiently fabricate and assemble all types of custom commercial ductwork and fittings. Ordering through MacDuct provides you with the largest selection of quality sheet metal duct types, duct fittings, stainless steel and welded ducts in the Pacific Northwest. If you need ductwork for your project, MacDuct fabricates your order quickly, for pickup or delivery directly to your job site.


When it comes to Multi-Trade Prefabrication, MacMiller is ahead of the curve. As experts in design, coordination, planning, scheduling and hosting the prefabrication of multi-trade racks in our fabrication shop, we’ve executed an array of complex projects. This high level of offsite prefabrication reduces project scheduling, onsite installation time, and improves workforce safety!

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We make buildings work better.