The prospect of building your dream home is exciting as well as daunting. If you don’t have experience in construction, it can be difficult to know if your home will withstand the test of time. Contractors are not always obligated to involve a structural engineer when building; however, it can be well worth the time and cost to involve a structural engineer in the planning and design of your house so that you can be confident your home will be structurally sound.
Peace of Mind
In certain areas, like the Blue Ridge Mountains, houses are often built on steep slopes where prescriptive building codes are not always enough to cover the extreme conditions that exist. The single most common structural issue we see in the mountains is foundation settlement. This can lead to cracks in walls, doors that do not close or latch properly, water infiltration in a basement and other problems. The building codes provide certain requirements for foundations, such as the depth into the ground, but the width is left up to the contractor’s best judgment. Undersized footings are the leading cause of foundation settlement and structural engineering negates this problem by adequately sizing the footings for site conditions.
Another common structural complaint among homeowners is “bouncy floors” which is technically known as excessive live load deflection. There are provisions in building codes to control live load deflections, however, the limits set by the codes are often below homeowners comfort levels. Although these bouncy floors are not necessarily a safety concern, the resulting squeaking and movement can be distracting and uncomfortable. A structural engineer can design floor systems that allow the floor to be stiffer with less deflection. This specialized skill set and design from a structural engineer can make your home feel more comfortable and give you the peace of mind you deserve.
The photo above shows floor joists with a beam that were estimated by the contractor to be adequate. Although they met code requirements for strength, the vertical deflection as you walk across the floor system was calculated to be 1.6 inches. After engineering calculations were completed, the beam sizes were increased and the deflection was reduced to just 0.6 inches. The material cost difference between what was originally installed and what was engineered was only $115. A small price to pay for the comfort of walking across a solid floor.
“Apples to Apples” Bid Comparison
Another reason it is often advised to get a structural engineer to be a part of the construction of your new home is that it helps to more accurately determine the cost of construction. It is always wise to get at least three quotes for building your home. If you have a set of structural engineering plans, your contractors will be bidding “apples to apples”, and you are less likely to have someone under bid and then come back to you for additional cost later. When you have a complete set of structural engineering plans, your contractor is more likely to be able to give you a lump sum price for your project. This can be advantageous if you are on a very set budget and allows you to put the risk back onto the contractor for overages.
The structural engineering cost for a full set of plans is approximately 1-2% of the total project cost. In the grand scheme of things, this is minimal to ensure that your home is built to last.