How to build outdoor spaces that last
As I sit writing this in late February, it is well over 60 degrees outside. As a Colorado native, I’ve known what the rest of the country only learns when they move here—the weather is awesome, and we have sunshine and comfortably warm days through most of the winter at the lower elevations. Coloradoans love living the outdoors lifestyle.
As a structural engineer, I’ve designed dozens of outdoor living spaces. As with all projects, there is a drive to make the structure efficient, leaving more budget for the fun parts. That being said: do not give in to the temptation to go too cheap on your structure. If you are going the design-build route, get multiple bids, and dump any bids that are significantly lower than the average.
Related: Beyond Curb Appeal
Most importantly, know your soil conditions and get your structural engineer involved early so you can dedicate adequate funds to the foundation. If you don’t have a soils report for the primary structure(s) on your property, get one for your project. Considering the cost of any construction project, it is worth the investment to provide your structural engineer the information needed to design a foundation appropriate for your site.
There is a strong trend to put outdoor living spaces on monolithic slab foundations. This doesn’t provide frost protection to open or unheated structures, which can cause foundation movement during the few truly cold weeks we get each year. Also, the high prevalence of expansive clays in Colorado can cause foundation movement, having a major impact on the future aesthetics of your outdoor space. If your outdoor space has any structural connection to other structures, it is best practice to match foundation types.
Colorado is a very windy state. Your pergola or patio/deck roof will likely experience gusts over its lifespan that approach hurricane force winds. The pressure these winds place on your structure are very real, and careful design is required to keep it from blowing over—and to prevent roofs covering outdoor living spaces from becoming airborne debris littering your neighbor’s yard. While forces from wind can be transferred to an existing structure, both the connections to the existing structure and the structure itself need to be evaluated for those loads. Failure to do so can result in the new structure pulling free and/or causing damage to the original structure.
Related: High-Tech Design – The Key to Seamlessly Blending Indoor and Outdoor Spaces
Snow loads and construction material self-weight are also very real. We sometimes go years between major snow events. However, structural engineers spend several weeks visiting properties damaged by the weight of snow every time we have a storm that delivers design snow loads. Supporting a new roof structure on an existing building adds new load to the existing structure. The original building needs to be evaluated for those new loads, including evaluation of the vertical framing (walls), horizontal framing (window and door headers) and the foundation. Attaching a new roof to an existing building can also change where snow drifts occur on the original building, or the size of drifts.
Outdoor structures, compared to the primary structures on a property, are usually considered minor buildings. However, even a small outdoor structure without amenities can easily cost $30,000 or more. The combined price for a geotechnical engineer and a structural engineer on this type of structure can be over $5,000. Spending 17% of the construction budget on engineering is admittedly out of proportion when compared to larger projects. However, it is cheap insurance to make sure that the end user can continue to enjoy their time in that space for years to come.
VIEW THE FULL ARTICLE IN OUR DIGITAL EDITION
