This project spotlight shares the design process for a modern house addition in Columbus, Ohio. Find out more about this project on our project page.
In this post, we’re picking up where we left off in sharing the evolution of the design for our Howard Addition. In this post, we share key strategies that helped us reduce costs which helped us save 15-20% of the construction cost to help create a more affordable home addition.
To get up to speed on this project, read about the concept design process in Part I of the story: Behind the Design Concept: Howard Addition.
Follow along as we continue our design process.
The Project (A brief summary)
To accommodate the dynamic lifestyle of a young family and appeal to their modern tastes, an existing kitchen gets a renovation and expansion including a new dining area and mudroom entrance.
The project extends the rear of the house 16 feet to create approximately 325sf of additional living space and back entrance. Other than the typical requirements of a kitchen, the renovated space needed to accommodate casual dining and a work area for the children with enough space for the family before, during, and after meal times. The mudroom, separate and contained, will open to a vaulted ceiling great room maximizing natural light and exuding a feeling of spacious in an otherwise smaller room.
Design Development
As we mentioned in the previous post, cost estimates at the end of the concept design phase came in a little high.
Moving into the design development phase, we looked at ways we could reduce costs. In our post, Over Budget? How to Reduce Construction Cost During Design, we talked about the three big ways to reduce cost during design: reduce scope, reduce complexity, and change materials and systems.
We used all three of these strategies to create a more affordable house addition for our clients. Here’s now:
Optimizing the floor plan
To start the design development phase, we reviewed the floor plan for space efficiency and confirming that the sizes of the rooms were appropriate for their functions. During this exercise, we were able to reduce the length of the great room by 18 inches.
While this may seem marginal, its impact has wide-sweeping effects on the budget.
Shaving off a few square feet reduces the amount of excavation, site work, foundations, framing, finishes, cladding, insulation, roofing, waterproofing, trim work, window sizes and MEP coverage, not to mention savings in energy usage when living in the space. Every little bit helps!
We also reduced complexity in the footprint by adding a small closet in the mudroom against the bathroom wall. Previously, we had a jog in the footprint to save the bathroom window, but we opted to forego the small window in exchange for more mudroom storage AND a simplified footprint.
Engineering for large window openings
During this time, we also enlisted the help of a structural engineer to size the beams and posts for the large openings in the exterior walls. We wanted large window openings so during the conceptual design phase we assumed a few larger beams would be needed to support the roof and stabilize the structure. Now was the time we figured out what those would be.
We hoped to use wood posts and beams to simplify the construction process and save costs. Unfortunately, our engineer came back with some unfortunate news that we would need to use steel framing. Ugh!
Due to the large openings, there wouldn’t be enough solid walls in the south exterior wall to resist the potential lateral loads imposed on the structure with wood framing. We would have to use structural steel to achieve this.
In order to use conventional wood framing, we needed to provide three more linear feet of solid wall along the south wall. While we love the small framing sizes of structural steel, we didn’t want to increase the cost of the project significantly.
The two perspectives below show our options. On the left, our current scheme (with steel framing). On the right, the scheme using wood framing.
Option 1: Steel framing
Option 2 Wood framing (savings: $18,000)
Unfortunately, switching to wood changes the look of the addition. (Notice the thicker walls at the corners of the addition in the above image.) No longer would the addition read like a glass box with a sloped roof.
It was a tough compromise, probably the biggest concession on the project, but given the significant cost of steel (union labor, higher material costs, and crane rentals), we made the decision to go with wood framing and save $18,000.
Product and material specification
The biggest remaining components left on the project to design and detail were the windows and cabinetry. These were big-ticket items that could have sweeping cost variations depending on both the sourcing and the detailing.
Windows
For a house addition with mostly all window walls, we knew that a large percentage of the total budget would go towards the windows.
Labor and material costs are higher for projects with larger windows and a large quantity of windows, but it’s a compromise that many homeowners are willing to make for the benefit of having more daylight and views.
During the design process, we considered the placement, design, and manufacturer of the windows.
Knowing that operable windows cost more than stationary ones, we strategically placed a few operables in the design while keeping the rest of the windows fixed.
Also, the code requirement for tempered glass required all glass within 18″ of the floor to be tempered – which is more expensive. To prevent tempering large floor to ceiling windows, we made sure to break up the windows so that only the lower windows near the floor needed to be tempered.
As for the manufacturer, we wanted to use Marvin’s Integrity All-Ultrex windows for their slim window frame sizes and material durability. But after reviewing the window estimates, we decided to switch to Andersen’s 100 Series windows which have slightly larger frames but were, for the most part, similar in design and more cost-effective.
Below, on the left: Marvin’s windows. On the right:: Andersen windows.
Left Photo: Modern on the Marsh by Kevin Browne Architecture. Photo by Jeff Roberts.
Right Photo: Queen Anne Residence by Lee Edwards. Photo by Miguel Edwards.
In the end, between all of our cost-saving strategies for windows: reducing the footprint (less glazing), adding solid wall to the south elevation, including mostly fixed windows with only a few operables, tempering only the lower windows, and switching manufacturers, we were able to save $8,000.
Cabinetry
Like windows, cabinets vary in quality and cost. Because we were completely updating the kitchen, we knew the cabinetry cost would be significant. Kitchen renovations can easily cost $50k with cabinetry consuming a large chunk of that budget.
Custom cabinets were not an option given the project’s budget, so we considered semi-custom and the readily available Ikea cabinets.
Ikea cabinets have the reputation of being a poor quality so we wanted to either confirm or strike down this accusation. Together with our clients, we went to Ikea and scrutinized the quality and design of the cabinets.
Our clients were actually impressed with the variety of sizes, configurations, accessories, and storage enhancements available. They didn’t think that there was anything subpar about the quality and were therefore open to using them, especially knowing that the cost was considerably lower than custom cabinets, nearly 1/3 the price.
The downside to Ikea cabinets is their limited selection of cabinet fronts, both in terms of finishes and styles. We wanted modern flat slab fronts and knew our options were limited with Ikea.
We considered a company like semihandmade who provides custom cabinet fronts made specifically for Ikea cabinets as a workaround to getting the aesthetic we wanted.
However, in the end, our clients actually liked the Askersund line of Ikea cabinet fronts which look like Ash wood, so we decided to stick with them.
In working with our client, we configured the individual cabinets to meet their kitchen storage needs.
In the end, uniformity reigned. We opted for Ikea’s 2-drawer cabinets for all base cabinets. Within the drawers, additional smaller drawers could be added as desired for the smaller storage needs but on the outside, the 2-drawer looked prevailed.
We also re-purposed Ikea cabinets for the storage bins under the mudroom bench which provided consistency in style, finish, and design throughout the renovation.
Phasing the project
The last thing we considered was phasing the project. To keep costs within budget, we considered whether any components of the project could be deferred to a later date when the budget allowed. Our clients were keen on maintaining the design intent because they loved the design and everything we’ve done together up to this point to realize their vision.
The most logical parts of a project to parcel out and save for later are those that are isolated components. Meaning, the effort to complete that work wouldn’t impact the rest of the house, or if it does, then it would be only marginal.
We decided that the landscape scope (a new back patio) and re-painting the exterior of the house were isolated design updates that could easily be done later. Removing this scope freed up funds that the clients could use elsewhere or keep for contingency.
Because we were discussing these things during the design phase, we were able to plan accordingly for the upcoming color change. We even went so far as to confirm that the cladding color for the new addition would compliment both the current house color and the future chosen house color.
In a similar vein, we were able to pre-select the color palette for the stone pavers and surrounding landscape features to anticipate the new color scheme for the house.
Final design perspectives
Construction Documents
With a majority of the design complete, all that was left was to create permit and construction drawings.
Framing information from our engineer was incorporated into the floor plans, foundation plans, and framing drawings.
With window information from the manufacturer, we created window details showing how the windows sat in the wall, how waterproofing and flashing would be installed, and how trim work and finish materials related.
Interior elevations showed the kitchen cabinet layout with exact sizes and configurations from Ikea’s kitchen catalog, and other interior finishes were noted.
A well-documented set of drawings including code drawings, plans, framing plans, sections, elevations, wall sections, details, schedules, lighting, electrical layouts, and interior elevations amounted to 18 full-sized drawings.
These construction documents provided city officials with the information necessary to issue a building permit and for the contractor to build the project.
Summary
Going from conceptual design to construction documentation is a big jump in drawing refinement. Early on during conceptual design, you have to make a bunch of assumptions. But the important task at hand is to nail down the initial concept. As the design process unfolds, the earlier assumptions are slowly confirmed or revised as you learn more information from the clients, engineers, vendors, contractors, and as the details are drawn.
The most important thing to remember during the evolution of the design is to make sure the design intent stays intact.
Early project goals dictate the design intent. It’s important to not dilute the design or lose sight of the big WHY for the project. Stay clear of shiny object syndrome and wanting everything you see in those fancy pictures.
For this project, the design intent was to create a spacious and multi-purpose dining space that was modern, but not trendy and that was cost-effective. Through deliberate decisions throughout the process, we were able to make this happen.
Our clients got the large windows and voluminous space but had to make some concessions to stay within their budget. The biggest compromise was the switch from structural steel to conventional wood framing requiring more solid wall on the south elevation.
But, overall, our clients are very happy with the design and have enjoyed the design process. They’ve seen an idea come to life that they previously never thought possible. They were proactive during the design process weighing their choices against the bigger design goals and being active participants in the evolution of the design. Now they are excited about the next steps.
The current trade war has boosted steel prices 10% overnight. Who is actually getting the boost in income is not clear. Was the frame to be all shop welded? Making a crane necessary. I like Zola windows. Was the potential sheer forces from 90 mph wind loading? I think you made good choices.