We’re excited to officially announce the new Wilkus Architects office in Hopkins, MN!

15 9th Avenue North | Hopkins, MN 55343

So far, we've launched the #WilkusRelocation project and discussed the importance of bringing in natural light. Today, we're delving into what it takes to create a warm, dry and energy efficient space. More specifically, we're inspecting how the roof plays an important role in satisfying these crucial requirements.


Designing a project in a northern climate brings many challenging architectural hurdles. Most of these challenges are related to the climate; heavy snowfalls and sub-zero temperatures can wreak havoc on a building. From a structural perspective, one must account for heavy snow loads when calculating the capacities of existing and proposed structural members. Snow can be extremely heavy and it provides excess weight that the roof doesn't need to support in warmer months. In addition, deflection must be considered as these structural members withstand varying loads throughout the year.

Architecturally speaking, the envelope is our first line of defense against thermal fluctuation and penetration. The roof is one of the most important pieces of this envelope.

"Just as your winter beanie keeps your head warm in the winter, so does an appropriate roof assembly for a building."

Above our new office, we discovered an insufficient roof assembly during the site assessment phase (See image on the left). The existing roof was made up of a ballast atop minimal insulation on a tongue and groove wood deck. This deck is supported by wood joists which transfer their load onto interior steel columns and the exterior bearing wall.

In order to ensure a warm, dry and energy efficient space, we needed to address the roof construction assembly. Originally from the 1950's, construction and material technologies have evolved considerably. Therefore, we opted to demo the entire roof from the wood deck up. This included all parapet flashing, ballast, waterproof membranes and roof insulation. (See image below) It's very telling to see how tired the roof materials were. Years and years of climatic abuse became very apparent during demolition.


The new roof assembly consists of a white PVC membrane, 5/8" coverboard, 3" minimum of R-18.5 rigid insulation and 5/8" OSB sheathing. The white PVC membrane will not only ensure that water is kept out, but it will also reflect the warm solar gains throughout the year. This helps to minimize mechanical loads for cooling the building while the added rigid insulation helps to minimize mechanical loads for heating the space.

Designing and specifying an adequate roof assembly within different climates can be difficult. As architects and designers we're challenged with the task of educating ourselves on how the built environment responds to these climates. We must stay informed and maintain currency as materials, codes and client expectations continue to evolve.


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