It’s a question I’m often asked. That being: “I’d like to add on to an existing building instead of starting from scratch. The building is good enough and I have a plan. Can you do that?”
While you may think that adding on to existing will save you money in the short-term, consider some of the benefits of detached, stand-along buildings—and the risks you may run into when attaching on to current structures.
The recent rash of building collapses across Western Canada due to heavy snowload highlights the importance of constructing your building to code—and doing it in the strongest possible manner. Building stand-alone, robust structures can help mitigate your risk, versus adding on to an existing building which may weakening a building’s structural integrity.
Consider the following risks before adding on to existing buildings
- Increased risk of structural failure: Adjoining a new building to an existing structure adds a new, different element that would not have been planned for in the initial building specs and design. The existing building is put at increased risk for failure by adding on, changing roof lines, etc.
- Technical challenges: The process of adding on to existing structures is rarely straightforward. Your costs to include more complicated construction procedures and additional labour will be higher than a stand-alone build.
- Local codes: It is much easier—and safer—to construct a new building to meet local codes than adjoining two others from a code perspective.
- Future building problems: Consider how a new building may settle differently than a building that has been around for many years. You may experience settling and heaving issues between the two. Frost can also cause a problem where the two structures join.
- Less value: In the long-run, you will get much more value for your dollar by building new, not having to navigate the complexities, and the potential risks associated with adding on to existing structures (which may also drive your insurance up).
- Less attractive: Often, finishing materials like metal siding, can be difficult to match to existing siding from different suppliers, leaving you with mismatched colour tones.
Keep these points in mind if you’re thinking about an addition to your building. By constructing a stand-alone building, you will have a robust building that will give you more value for money—and less headaches—in the long-run.
MORE TIPS FOR A STRONG ROOFING SYSTEM
Brent Feyter, Senior Designer with Structural Truss Systems in Fort Macleod, Alberta, has more tips on ensuring strong roof systems.
“Every winter it seems we get the news reports of roof systems failing, both farm and commercial, due to large snowfalls and every time it begs the questions as to what can be done to avoid failures in the future,” says Brent Feyter, Senior Designer with Structural Truss Systems in Fort Macleod. “Every failure will have its own causes or contributing circumstances so it’s good to be aware of what some of these can be in order to prevent future failures as much as possible.”
Here are a few things to consider when building a new building, or if need be, adding to an existing building:
- Trusses can be designed with slippery roof reduction factor because of snow sliding off the metal roofing. Before installing snow stops or a new valley system for an addition, check to ensure the trusses were not designed for a slippery roof reduction.
- Trusses can be designed with a wind swept snow reduction factor assuming some snow will blow off the roof instead of accumulating. This is ok as long as no new obstructions are added around the building like tall feed mills, trees, or another building.
- Additional unaccounted for loads can also come from store fronts, venting stacks, new adjacent buildings or any other obstruction causing excessive snow accumulation on the roof.
“Engineered wood roof trusses are designed for the loads specific to their intended use, based on the information truss designers receive–so the more information supplied, the better,” says Feyter. “For more information on engineered wood roof trusses, visit the Western Wood Truss Association of Alberta website.”
