Hidden Creek Community Envelope Project

Title: Hidden Creek Community Envelope Project

Award Category: Building Enclosure

Project Address/Location

2100 Canyon Resorts Dr.

Park City, Utah 84098
United States

Submitted By: Carl Greene

Company Info

McNeil Engineering

8610 Sandy Parkway
Suite 200
Sandy, Utah 84070
United States

8012557700

[email protected]

Project Description and Background: The Hidden Creek Community was originally constructed in the 1970s. A total of 38 buildings were constructed in 2 primary styles, described as 'Georgetown' and 'Townhome.' Buildings consist of single-resident, duplexes, triplexes, and 4-plexes, with a total of 138 individually owned units. They have undergone several re-roofing projects and dozens of unit owner modifications over the ensuing 4+ decades. All walls are 2x4 wood stud construction and roofs are stick framed with 2x10s. Fiberglass batt insulation was the original insulating material. In 2001 an engineering consultant recommended that all roofs be reinforced and the insulation in the walls be addressed. A similar report was created in 2019 and again in 2021. Due to projected costs, each of the previous HOA boards had put the project off. Finally, after the events of the collapse of the apartment building in Surfside, Florida, the HOA board in 2021 decided to take action on the previous reports. Our office was brought in in 2022 to help with was initially only meant to be a re-roofing project. After we conducted our own analysis of the community buildings and researched the previous reports, we recommended that the scope expand beyond the roofs and include the entire building envelope of every building in the community.

Scope: Working with the contractor that had been brought on in 2021, we examined the roof framing, roof insulation, wall framing, wall insulation, and exterior wall systems for both of the building styles on site. Our structural engineering team identified that the existing roof framing was not adequate to meet current IBC required loading. We also determined that the existing batt insultion did not meet current IBC requirements for that environment. The exterior wall assemblies showed extensive spreading of microbial growth, poor and degraded batt insulation, fiberboard wall panel sheathing, and no vapor retarder below the existing wood siding finish. Over the course of the community's history, most units had experience leaking through the roof, many had leaks through the walls, and most had dealt with microbial growth. Previous projects had tried to address some of the issues with the roofs, but nothing had been done over the history of the community to address all of these issues.

Solution: The first issue to address were the undersized and underinsulated roofing systems. Our solution involved removing roof decking, cleaning out the existing batt insulation, and replacing them with new R-30 batts. We also upgraded the roof framing so that each roof met the gravity snow loading requirements of the 2018 IBC. In this climate an R-49 is required by code, so we added a new cold-roof system on everybuilding, consisting of ventilated, insulated panels so we could get the R value to R-50 and so we could provide ventilation below the shingle layer for extended warranties from the shingle manufacturer. To properly flash and waterproof the roof-to-wall connections, we removed all existing siding. This allowed us to removed the useless fiberboard wall panels and to clear out the degraded wall insulation. The insulation was replaced with R-15 batts. Sill plates were treated for microbial growth, framing was replaced or reinforced as needed, and new wood panel sheathing was installed to improve seismic performance and to provide the required nail base for new composite siding warranties. All windows were replaced with new double pane, low-E, fiberglass windows, fully flashed into the new water resistive barrier added to the wall system. To provide air movement with the individual units, we provided energy recovery ventilators (ERVs) to pull and push air throughout units that did not have a forced air unit system installed for heating or cooling. The completed units will now perform better structurally, use a fraction of the energy previously needed for heating and cooling, have an exterior finish that will last through the life of the buildings, and all of the units display the same finish materials and colors, tying the community together as a whole visually.

Value: The large scope of this project is the result of our involvement as building envelope consultants. Without our help and counsel, the less informed members of the HOA board would have pressed for solutions to cut costs at the expense of accomplishing any real change to the buildings. Each decision to peel back another layer of the onion was met with resistance and valid concerns about cost and impact. Our prior experience and association with a knowledgeable communit helped us to address each of the concerns and then to work with the HOA board and the contractor to find a resolution that addressed the base issue and complied with financial concerns and community aesthetics. Ours was the voice of reason when there were multiple contradictory opinions. Members of the board thanked us for our unwaivering stance to make the community buildings better and felt that our involvement helped to achieve that end.

Additional Info: This project spanned over 2 years to complete. The HOA board changed in the middle of construction with little to no impact to the scope of work being completed. Some of the more industrious unit owners had refinished their entire units in the recent past, requiring us to work around areas of spray-foam insulation and unexpected structural issues.

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