The Blueprint for a Perfect Construction Design-Build Proposal.
Design-Build Project Proposal Review
Four Building project
Preliminary Drawings
Value Engineering Suggestions
Life Cycle Cost Analysis
A 7 Bay Storage Building 115’ x 40’
An alternate 12 Bay Storage Building 165 x 40’
Retail Building, 210’ x 40’
An Alternate 3-story Storage Building, 210’ x 40’
To review this Design-Build project, I presented preliminary 2D and 3D drawings and a construction estimate so that the Owner could review and make a decision on continuing with the project.
This preliminary estimate will help the Owner assess the feasibility early in their project review. It is a rough order of magnitude (ROM) of the construction costs that are based on my past similar projects. My initial estimate would be a square foot cost.
I also provided a more detailed estimate based on the takeoff of the materials from the drawings.
Detailed Preliminary Estimate
Value Engineering Analysis
At this preliminary stage, I also provided Value Engineering suggestions that would eliminate unnecessary costs while maintaining or even enhancing the project's performance, quality, and functionality.
Life Cycle Cost Analysis (LCCA)
I performed a preliminary life cycle cost analysis for the three-story climate-controlled storage building.
A Life Cycle Cost Analysis (LCCA) during the preliminary design stage is a method I use to evaluate the total cost of a building or building system over its entire lifespan.
The goal is to identify the design that offers the lowest overall cost of ownership while meeting the project's performance requirements and quality standards.
This includes expenses related to energy consumption (heating, cooling, lighting).
A further analysis, which I did not perform, would include maintenance and repair costs throughout the building’s life. For this analysis, I assumed that the maintenance and repair costs would be similar for the different components.
At the preliminary design stage, LCCA can help evaluate the trade-offs between a higher initial investment in more durable or energy-efficient materials versus lower upfront costs with potentially higher long-term operating and maintenance expenses.
In essence, LCCA during the preliminary design stage shifts the focus from short-term cost savings to long-term value optimization, ensuring that decisions made early in the project consider the total cost of ownership.
Owners who hold on to their buildings for an extended period would be more likely to review a life cycle cost analysis.
The design costs are included in the preliminary estimate. The design disciplines would be a Geotechnical soils report, structural foundation design, civil design, and an Architectural drawing.
This preliminary estimate is based on my past historical projects.
Here is my review of one of the proposed buildings.
Three-story, climate-controlled Storage building.
1st Floor, 66-5’x5’ units, 39-10’x5’, 31-15’x5’
2nd Floor, 97-5’x5’ units, 2-10’x5’, 35-15’x5’
3rd Floor, 97-5’x5’ units, 2-10’x5’, 35-15’x5’
Total 261-5’x5’ units, 43-10’x5’, 101-15’x5’
The storage building, as you see, I have figured as a wood-framed building. We would design and construct the building within the wind loads in Huntsville with shear walls and hurricane tie downs. I believe that the wood frame building would be the most cost-effective for the project. We figure floor trusses and an AdvanTech ¾” subfloor.
AdvanTech subflooring is a premium subfloor option that offers significant advantages in terms of moisture resistance, strength, stability, and ease of installation, ultimately contributing to a higher-quality and longer-lasting floor system. While it may have a higher initial cost compared to standard OSB or plywood, the long-term benefits and reduced risk of problems often make it a worthwhile investment.
Exterior Wall Construction
The Code calls for R-13 for walls, R-5 continuous, and R-38 for a ventilated attic space. Ventilated attic.
We will look at constructing a Zip Board insulating sheathing. The sheathing has an
Integrated Water and Air Barrier: The primary advantage is the built-in water-resistive barrier (WRB) and air barrier. This eliminates the need for a separate house wrap, saving time and labor during installation. We will simply install the panels and tape the seams with compatible ZIP System tape to create a continuous barrier.
The R-values for insulated zip board sheathing range depending on the thickness of the foam layer, such as R-3.6, R-6.6, R-9.6, and R-12.6.
We can integrate that with a closed-cell or open-cell spray foam insulation on the exterior of the 2x6 walls. The R-factor per inch of open-cell spray foam insulation is R-3.5. The R-factor per inch for closed-cell spray foam insulation is R-6.0.
The insulation of this structure will affect the size of the Air Conditioning units. And it will also affect the monthly electricity costs. I estimated the size of the Air Conditioning system at three (3) - 7-ton AC systems, figuring 12,000 SF per ton, one unit per floor. To properly design the Air Conditioning, it would be necessary to perform a Manual J calculation of the building.
Manual J Calculation of the HVAC System
A Manual J, developed by the Air Conditioning Contractors of America (ACCA), is the foundation for designing the mechanical (HVAC - Heating, Ventilation, and Air Conditioning) systems of a building. It functions by performing a detailed heat load calculation to determine the precise heating and cooling capacities needed to maintain the building.
A Manual J acts as the crucial first step in a well-designed HVAC system. By accurately quantifying the heating and cooling demands of a building, it ensures that the subsequent equipment selection and distribution system design are based on actual needs, leading to:
• Improved Comfort: Consistent and even temperatures throughout the building.
• Enhanced Energy Efficiency: Properly sized equipment operates more efficiently, reducing energy consumption and utility bills.
• Increased Equipment Lifespan: Equipment that isn't constantly overworking or short cycling tends to last longer.
• Better Humidity Control: Properly sized cooling equipment can effectively remove humidity in humid climates.
• Code Compliance: Many building codes now require Manual J calculations for new construction and significant renovations.
Therefore, a Manual J calculation is not just a recommendation but a fundamental practice for designing effective and efficient mechanical systems in buildings.
Value Engineering Options
The Code calls for a 14 SEER (Seasonal Energy Efficiency Ratio) Air Conditioning system.
I looked at installing an 18 SEER heat pump AC unit and an Energy Recovery Ventilator (ERV) for each of your three 7-ton AC units in Texas.
Both components would add to the overall cost of the project at the front end. The savings come from a Life Cycle cost analysis in their savings in electricity.
I have installed an 18 SEER heat pump model on my last project, and the Owner received savings on his monthly electric bill.
Let’s look at both items.
18 SEER model Heat Pump AC Unit versus a 14 SEER model. The 14 SEER is the code for this climate zone. SEER measures the cooling efficiency of an AC unit over a typical cooling season. A higher SEER rating means more cooling output for each unit of electricity consumed. Moving from 14 SEER to 18 SEER represents a significant increase in efficiency. Based on my previous project, I figure an approximate reduction in energy consumption could be achieved by 25%.
In my estimate of the energy cost, the AC units consumed around 4284 kWh per month, costing approximately $514.08 (at $0.12/kWh). A 25% reduction in this cost would be $128.52 per month. This is just for one AC unit. With three units, the total estimated monthly savings could be around $385.56.
18 SEER heat pump units will have a higher initial purchase price compared to the 14 SEER AC units. I estimated an increase of $2000 per unit.
Energy Recovery Ventilators (ERVs) for Each AC Unit:
ERVs work by exchanging heat and humidity between the incoming fresh air and the outgoing stale, conditioned air. In the cooling season:
The ERV pre-cools and dehumidifies the incoming warm, humid outside air using the cool, dry exhaust air. This reduces the load on your AC units.
In the heating season, the ERV pre-heats the incoming cold air using the warm exhaust air, reducing the load on the heating system (heat pump in this case). I estimated $6,800 for each ERV.
I estimated a 15% reduction in cooling load based on my past project that we recently completed. (The project is in climate zone 3.)
Savings per AC unit: 0.15 * $514.08 = $77.11 per month
Total savings for three units: $77.11/unit * 3 units = $231.33 per month
Life Cycle Cost Analysis
Combined Potential Savings:
If you implement both the 18 SEER heat pump AC units and ERVs for each unit, the estimated total monthly electrical cost savings on your AC operation could be:
$385.56 (from higher SEER) + $231.33 (from ERVs) = $616.89 per month.
Total Estimated Monthly Electrical Cost with Upgrades (Rough):
Previous Estimated Total Monthly Cost: $960.42 (This was a very rough estimate). Estimated savings $960.42 - $616.89 = $343.53 per month.
Therefore, the Return on Investment (ROI) on the increased 18 SEER units ($2,000 x 3 = $6,000) and ERVs ($6,800 x 3= $20,400). Total investment $26,400.
Electric savings $343.53 per month = $4,122.36 per year. Payback on investment would then be 6-½ years. The Panasonic ERV has a 6-year warranty. The maintenance on the unit is replacing the filters every 6 months. You expect a life span between 15-20 years. You may have to replace a small motor in that time frame. A Carrier AC has a 10-year warranty. And you expect a life span similar to the ERV, with maintenance of cleaning coils and recharging the system.
Another Value Engineering option is to construct ½” OSB Sheathing with Tyvek building wrap and ½” rigid foam insulation.
Two suggestions for rigid foam insulation.
Expanded Polystyrene (EPS): This is the least expensive type and has an R-value of R-3.8 per inch.
Polyisocyanurate (Polyiso): This type boasts the highest R-value per inch, generally ranging from R-6.5 to R-6.8. It often comes with a foil facing, which can also act as a radiant barrier.
I have substituted this exterior wall system instead of the Zip Board assembly. There is a substantial savings, and it is contingent on the R factor sheathing that you use and the thickness of the rigid foam insulation.
The amount of insulation and the cost of it determine the Cooling load of the building, thus determining the size of the Air Conditioning units.
Better insulation creates a more efficient building, which will lower your monthly electric costs. Lower costs mean higher net operating income, which increases the building’s value.
Design-Build Advantages
The Design-Build project proposal enables the Owner to have a single point of responsibility for the design and construction of their project.
Its Streamlined communication pathways result in faster decision-making and more efficient problem-solving.
The design and construction phases can overlap and can provide a faster project completion.
Having my company involved during the design phase allows for value engineering and consideration of constructability, potentially leading to cost savings and fewer change orders due to design issues.
My integrated team shares a vested interest in delivering a high-quality project. The close collaboration between design and construction professionals can lead to more buildable designs and better execution.
Shifting the responsibility for both design and construction to us as a single entity reduces the owner's exposure to risks associated with design errors, constructability issues, and coordination problems between separate teams.
The close working relationship between my designers and us as builders can foster innovative solutions to design challenges and construction complexities.
My team can collaboratively explore different materials, methods, and technologies to optimize the project's outcome.
Cost considerations are integrated into the design process from the beginning, allowing for more accurate budgeting and reducing the likelihood of significant cost overruns.
The single point of contact and collaborative approach can lead to a more positive and transparent working relationship between the owner and the design-build team.
For many projects, the benefits of efficiency, cost control, and streamlined processes make our Design-Build a highly attractive option.
Shettig Construction Management provides Professional Design-Build Construction Management services from the inception of your project through completion. www.shettig.com mshettig@gmail.com
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