Suppose that you have purchased some land, and the plans have been finalized. Your contractor is waiting for you, and you're ready to break ground. After 3 weeks, the excavation crew stumbles upon a layer of rock that no one had anticipated. Or you find out the border is located 2 meters in from where you believed it was. Then, the budget goes out the window and the timeline is off.
This occurs more often than many realize and could have been avoided in most cases with a site survey prior to construction. Ever wonder, "What is a site survey, and what do I need it for?"
What is a site survey?
A site survey is an in-depth examination and documentation of a land area before construction work is started. The property's boundaries, dimensions, elevation, soil quality, natural features, utilities, and structures are surveyed and documented by a surveyor or engineer. The outcome is drawings, maps, and reports that architects, engineers, contractors, and estimators can use to devise the project.
Consider it a land health checkup. Doctors perform tests before prescribing treatment. A survey reveals what you are working with before you build.
What is the purpose of a site survey prior to construction?
1. It can identify your property boundaries.
One of the most frequently cited and most costly construction issues is boundary disputes. A survey lets you know precisely where your land is and where it ends—you're not building over the neighbor's property, and you don't need to violate setback rules. If the boundary error in the construction is discovered later, there are potential legal issues, demolition or both.
3. It provides a clear idea of the state of the land.
You don't often see the actual property when you look at a paper. A survey shows you:
• The effects of slopes and changes in elevation on foundations and drainage
• The soil type and bearing capacity that determine the strength of your foundation
• Water tables and flood risk, impacts on waterproofing, and site preparation
• Trees, rocks, and obstacles that may require removal.
This information can be used to inform the design process, rather than to struggle with the site later.
3. It locates both below- and above-ground utilities.
Often water lines, sewer pipes, gas and electrical lines are buried. If hit during excavation, it is hazardous and expensive. A survey will be useful to identify their presence and enable the design to be developed around them or to be considered safe to move them.
4. It approves the legal and regulatory aspects.
A lot of local municipalities will not issue a building permit without the survey documents. Your project is in accordance with the zoning requirements, setbacks and easements, and land usage regulations. If not, its approval can be stifled even before it begins.
5. Makes the design more accurate
Architects and structural engineers don't use assumptions; they use actual measurements. They can get it right the first time with a good survey to help them plan and position the building, prepare drainage and access, and minimize rework.
6. It results in much more accurate cost estimates.
It's a task that many project owners forget to do. Your budget is impacted by: Excavation volume, filling, retaining walls, drainage, foundation type, and site access, all of these are survey information. If you don't have a survey, an estimate is very much a wild guess. One, it's rooted in real numbers. Hence the need for an estimator to request the survey data before creating a quantity take-off or bill of quantities.
Common Types of Site Surveys
Not all surveys are applicable to all projects. The most significant ones are:
• Survey of boundary: legally defines property lines and corners and detects encroachments.
• Topographic survey: draws contour lines, elevations, and natural and man-made features. Important for grading, drainage, and earthwork operations.
• Geotechnical (soil) survey: Involves testing soil strength, soil composition, and groundwater to help design foundations.
• Utility survey: Identifies utility services below and above ground.
• As-built survey: records what was actually built for verification and final documentation.
• Construction layout survey: shows the precise location of structures, foundations, and columns on the ground.
In general, a boundary survey, a topographic survey, and a soil investigation are good places to begin the process of a typical building project.
What if you don't conduct a site survey?
Avoiding a survey may save some money now, but the risks accumulate as you go:
• Unexpected excavation or soil stabilization expenses.
• Redesigned foundations during construction. Re-designed foundations in the middle of the construction process.
• Issues regarding boundaries/legal issues
• Damage to utilities and project delays.
• Under a budget, some budgets are too low due to an incomplete estimate.
• Allow for non-conformance or a penalty for non-compliance
In nearly all cases it is much more expensive to correct a problem later, after it has happened, than to make the survey correctly at the beginning.
A site survey is required to tie in the construction cost estimate.
An accurate construction estimate hinges on the information that is fed into it. The survey results are directly fed into:
• The volumes of earthwork (volumes of excavation and fill)
• The type and depth of foundations. The nature and depth of foundations.
• Removal of trees and vegetation, and demolition of structures.
• Drainage structures, retaining structures
• Access, temporary works, and logistics.
Survey data and estimation working together: no more “we didn't know it was there” conversations mid-job, clearer budgets for owners, and more confident bidding for contractors.
Frequently Asked Questions
Does a site survey have to be done prior to construction?
Yes, most at least a boundary or topographic survey, as permits are often based on it. This is dependent on the requirement, and you should ask your local authority.
How much time would a site survey require?
In the case of small residential plots, it could take a day or two. Larger or more complicated locations will take a week or longer, plus time for drawings to be prepared.
Who is doing a site survey?
Depending on the type of survey, licensed land surveyors and geotechnical engineers are involved.
What are the charges for a site survey?
This varies according to area or location, topography, and survey type. It is generally a very minor percentage of the overall project cost and frequently saves much more than it costs.
Do you have to perform a site survey to get a construction estimate?
It's possible to get a ballpark approximation, but it will be less precise. Data collected from surveys is much more accurate.
Conclusion
A site survey isn't simply a piece of paper. It's the backbones of the design, permits, the budget, and the schedule. Knowing the risks associated with your property prior to construction is one of the best and most cost-effective tips to safeguard your investment.
After your survey, what you need are accurate quantities and costs? Design Estimation offers construction estimation services that convert your drawings, plans, and site data into detailed, accurate cost breakdowns. For more information visit designestimation.com.
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