additions

additions

Discover period home additions by Arciform, where we design and build seamless custom expansions that merge flawlessly with your home's storied architecture.

A home addition can integrate naturally with your home, enhancing its character while providing the additional space you are looking for. We carefully consider architectural details, proportions, and materials to ensure a seamless blend of old and new.


In Portland's historic neighborhoods, we navigate the approval process, managing details, setbacks, lot coverage, and other city requirements to ensure smooth progress. With decades of experience, we navigate designing and building your addition both professionally and creatively.


A custom home addition improves your lifestyle, whether it's a light-filled kitchen expansion, a private primary suite, or a connection to the outdoors. We unite the new with the existing, considering codes, systems, and finishes for complete harmony.


Start planning your historic home addition and schedule your complimentary consultation with our design and build experts.

Enjoy a sampling of our home additions below and see the full project stories in our portfolio!

Enjoy a sampling of our home additions below and see the full project stories in our portfolio!

Enjoy a sampling of our home additions below and see the full project stories in our portfolio!

A well-planned addition can transform how you live in your home.

Whether you're expanding for a growing family, creating space to age in place, or finally getting that sunroom, we’ll help you design an addition that looks and feels like it’s always been there.

LET'S EXPLORE WHAT YOUR HOME CAN BECOME

A well-planned addition can transform how you live in your home.

Whether you're expanding for a growing family, creating space to age in place, or finally getting that sunroom, we’ll help you design an addition that looks and feels like it’s always been there.

LET'S EXPLORE WHAT YOUR HOME CAN BECOME

“If you’re looking for someone to create a space that seamlessly integrates with the rest of your house – especially an older historic home – I could not recommend Arciform highly enough.”

Dan Volkmer, Portland, OR

“The work crew did a great job of paying attention to small details so that the new part of our house flows seamlessly with the old and the new construction is very high quality as well. The crew also did a great job of being respectful of our family, as we lived in a portion of the whole house during almost all of the time of the remodel process. Thank you to one and all!”

Michelle, Portland, OR

“We have used Arciform for the remodel of our 1909 home in Portland Heights. Our project involved most of the house, in 3 phases over the course of a few years. We are absolutely thrilled with the end result. Arciform is a highly professional team, from start to finish.”

Lynn, Portland, OR

“This is an amazing design/build company. Anne and Richard have created something very special, highly ethical with the highest standards of service.”

Gretchen N., Portland, OR

“I did a significant remodel of my 2nd floor with Arciform about 18 months ago. They provided a lovely design, meticulous specifications and accurate bid and a high-quality finished product.”

Jan N., Portland, OR

Home Addition FAQs

  • How do I know if I can fit an addition on my property?

    Depending on the zoning of your property, the city of Portland has different requirements for how much of the property can be covered by buildings, as well as where we are allowed to build.  The city provides a great resource with the website www.portlandmaps.com, which lists your zoning, if you are near a conservation district, shows where your sewer ties into the public sewer system and many other parameters that are important to consider when starting any remodeling project. Even a dormer addition has to be built outside of your setback. We can apply for set back adjustments if your goals are outside of what the code allows.  Tree roots can also get in the way of your foundation and we sometimes need to manage the rainwater that runs of the new roof surface on your property. 

  • What are the first steps you take when designing an addition?

    Arciform walks the property and thoroughly investigates how best to tie into the existing rooflines and foundation, how the grade may dictate the type of foundation, if there are trees, AC units, gas meters, overhead or underground electrical connections, or are gas and plumbing lines in the way?  The city provides a free service called „call before you dig“ who comes out and marks underground piping to prevent especially gas lines from being damaged.

  • Can I build anything I want on my property?

    There are parameters depending on which neighborhood you are in.  Many neighborhoods have height restrictions; there are glazing requiems for esthetic as well as fire safety reasons; and historic neighborhoods have restrictions Arciform helps you navigate with regards to proportions, details, finish, and fixture selections.  There are also property specific parameters that we verify and document on your site plan.  We have to list the location, size and type of trees and make sure the addition does not damage the tree roots; we hire surveyors to help pinpoint the exact property line if we are planning close to your property’s edge or need to know the grade changes.  In most neighborhoods we have to account for parking on the property, and we have to consider where and how to tie into existing services.  We have to plan according to codes to keep fires from spreading fast between neighboring properties as well as your main structure and your garage or secondary dwelling units.

  • How does an addition affect the existing structure?

    Depending on the addition you are planning, in general it is easier to build out rather than on top of an existing structure.  When building outward we can manage most if not all of the additional wind and gravity loads within the new structure. When building a dormer or second story addition, the loads are being transferred onto the existing structure, which was not meant to capture those loads.  This can trigger many invasive structural changes that affect the lower levels. It may also be appropriate to consider seismic retrofitting at this time.

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