If you are in the early stages of planning a home renovation or new build, there's a good chance you've already started comparing prices.

That instinct isn't wrong, but it can lead you straight into the most expensive mistakes residential projects produce. Not during construction. Before the drawings are started.

This article is written for homeowners who are:

  • Comparing design service fees and wondering whether the cheaper option is "basically the same"
  • Thinking that drawings are drawings and that any competent person can produce what's needed
  • Trying to control project costs by starting with a target budget
  • Unsure where to start and looking for clarity on what actually matters

If any of those describe where you are right now, the next three sections are worth reading slowly.

Time and time again, homeowners learn the hard way that the most costly mistakes aren't made during construction; they're made in the weeks and months before a single drawing is started. The most costly mistakes are a result of early decisions made, before the drawings are started, and then shoe-horning solutions into place during the construction of the project.

In this article, three of the most consequential mistake categories are examined, along with their real-world impact and what to do instead. The good news is that these types of mistakes are predictable and avoidable.

Why Comparing Design Fees Misses the Point

Most homeowners compare design services on price per drawing, or on how quickly they can get permit-ready documents. That comparison treats design like a commodity, the same way you might compare two bags of the same flour at the grocery store.

But design services are not a commodity. The fee you pay up front is not the cost of the service. The cost is everything that follows from the decisions made (or not made) during the design phase.

A low-cost drawing service delivers pages. A thorough design process delivers decisions: tested, coordinated, and locked in before the contractor starts the clock. The difference between those two outcomes is often measured in the tens of thousands of dollars once construction begins.

For a deeper look at this distinction, see: Value Versus Price — The Difference Explained →

Mistake #1 — Designing Before Understanding the Building Site's Constraints

Impact: Major — Project Show Stopper
Service trenching being resolved on-site due to missing pre-construction site analysis
Figuring out service trenching on-site and on the fly because no one else had done so.

I've marvelled at how homeowners, new or experienced, start with visions of a beautiful home, selecting a design from a plan book or using images from Pinterest as the foundation for their dream house. Then the long journey to find a lot to accommodate this vision begins, often ending in frustration or significant compromise.

Low-cost drafting services reinforce this approach by offering an unrealistically low price point and fast "permit-ready drawings", services that homeowners quickly learn exclude any professional oversight or guidance. (I've even had to compete against suppliers who throw in the design fee as a loss leader, as long as the customer buys supplies from them.) These low-cost services just take your money and run, leaving you to deal with a project riddled with risk and expensive errors.

It happens so often that general contractors treat plans as a "suggestion" rather than the contractual documentation they are truly meant to represent between you, the municipality, and the contractor.

I know this first-hand because I've had to build from drawings like those I've described. The exercise is nothing short of being a constant source of frustration, anxiety, and emotional turmoil for all parties involved.

Here's how you avoid becoming a victim of Mistake #1: develop a thorough understanding of the site before you even consider drawing a single line, selecting a plan, or cutting down any trees. Unexpected issues such as drainage problems, road allowances, waterfront setbacks, mature tree preservation, and floodplain restrictions can render initial building plans completely unworkable — leading to the abandonment of final designs after significant emotional and monetary investment.

Key Site Factors That Must Be Understood Before You Hire Anyone

Property boundariesHave a recent up-to-date survey including all existing buildings, hardscape, and topography.
Zoning bylaws & subdivision covenantsEstablish building height, use, setbacks, allowable coverage, and material restrictions.
TopographyUse rather than fight the natural slope to lower costs for remedial cut and fill.
Lot accessNote driveways, culverts, or curb cuts. Some may be reused; others require new placement.
Utility service dropsLocate electrical poles and connection points; confirm whether service is underground, overhead, or unavailable.
Existing vegetationLots may be subject to mature tree coverage or shoreline preservation requirements.
Soil bearing capacity & stabilityImpossible to observe — the soil must be tested first.
Surface drainageAfter rain, standing water indicates saturation and poor drainage needing correction.
Floodplain & shoreline setbacksA nearby creek several streets away may prohibit a pool, workshop, or accessory dwelling.
Soil percolation rateImpossible to observe — requires a soil test pit professionally evaluated.
Sun, shade, & prevailing windsLeverage exposure for comfort and to reduce energy costs.
Easements & legal encumbrancesLegal rights granted to utilities or neighbors — read your property's deed thoroughly.
Septic, well, & drainage restrictionsSeptic systems have minimum setbacks, depth requirements, and surface area allocations.
Existing building permits (renovations)Illegal or unpermitted work is common and adds cost to correct once discovered.
Parking requirementsEnsure adequate space is available for anticipated parking needs.
Snow storage (northern climates)Disputes over neighbors' snow stockpiling are common. Allocate space deliberately.

Ask yourself this question before moving forward:

Do I have answers to all of the items above? If the answer is No to even one of them, stop now — and get those answers before hiring anyone.

A lack of understanding of any of these key items puts your project at real risk of unanticipated costs. Simple avoidable missteps lead to inefficient construction solutions, higher utility bills, and long-term mistakes that limit the enjoyment of the property.

Contractors are not responsible for your lack of due diligence — but they do profit from it. Studying the site early is inexpensive, necessary, and a sound investment.

Skipping early site analysis locks in expensive, long-term problems. Start with the site, and you lay the foundation for a home that works with — rather than against — its environment.

Real-world impact

In one Eastern Ontario new build, an unresolved floodplain setback was discovered after the foundation drawings were complete. The redesign cost $11,000 and delayed permit submission by six weeks. The design fee for the original drawings: $2,400. The information needed to prevent it was available at the municipal office for no charge.

Mistake #2 — Treating Drawings as a Commodity

Impact: Severe — Recoverable but Heavily Cost-Prohibitive
Improper waterproofing on an ICF foundation wall -- a leaky basement that resulted from skipping proper design review
Improper waterproofing detailing on an ICF foundation wall resulted in a flooded basement.

A costly mistake is treating drawings as just another administrative task, something to produce quickly so you can get the permit and start building. This thinking ignores the vital role that the drawings for the design play in achieving a livable, functional home.

Too often, homeowners undermine their projects with one belief: "We just need drawings for the permit." This mindset bypasses the valuable concept and schematic phases, which exist to explore solutions, assess feasibility, and ensure the design actually serves the homeowner's lifestyle, not the timetable and pressure applied by the contractor.

Let me give you a specific example of what this looks like in practice.

I once reviewed a design where the homeowner would have to carry dirty laundry from bedrooms and bathrooms, past the main foyer and front door, then across the living room to the utility area located behind the garage. Groceries followed a similar route: from the car, through the garage, across the living and dining areas, past the front entrance and then into the kitchen. The front entrance looked impressive from the street, yet had no closet for guests' coats or shoes. Coats were piled up on the bed in a child's bedroom. The guest's shoes were in a chaotic collection on the foyer floor at the entrance.

The garage sat on the southwest end. Large living windows faced north. The street could only be seen by opening the front door and stepping outside onto the front porch.

These plans were made just to get the permit, with no regard for daily living. When the design was examined, it failed to support practical activities. As a result, it was abandoned, and a new design was prepared. The homeowners paid for drawings twice.

In the concept phase, initial ideas are tested and compared — one kitchen layout versus another, one circulation path versus another. In the schematic phase, those ideas are refined into detailed floor plans and 3D visualizations that illustrate how spaces serve the homeowners' actual needs. These are not extra steps. They are the steps that determine whether what gets built is worth building.

Well-crafted design is built upon:

  • Understanding the problems you are trying to solve
  • Exploring options and selecting the best fit
  • Testing solutions to ensure they suit your lifestyle
  • Protecting your investment through informed, early decisions

Homeowners should focus on defining their problem, exploring and testing solutions, and selecting experienced professionals to work with. Careful selection means verifying credentials and insurance, asking for references, and reviewing past work. Strategic decisions made early in the design process protect investment and result in a home that is functional and satisfying for the long term.

Real-world impact

A homeowner who skips concept design and goes straight to permit drawings often receives a bid range of $180,000 to $290,000 for the same project — because the contractor is pricing the unknowns, not the work. A project that moves through concept and schematic design first typically produces a bid range of less than 12%, because the decisions that drive costs, materials, and quantities have already been made.

Mistake #3 — Making the Contractor Solve Design Problems

Impact: Very High — Costly Tear-Outs, Rework, and Delays
Gaps left in drawings that had to be solved on site during construction
Having to fill in the gaps because the draftsman left it up to the site to figure out.

I've walked onto a site where a critical structural beam location is shown placed directly over a non-load-bearing mechanical wall. The framing crew pointed out the error because they knew that since nobody had answered the question during design, they wanted to be sure they were paid to fix someone else's error. That decision to place the beam over the mechanical wall cost the homeowner an additional $14,000 to re-route the mechanical and plumbing components and frame in new mechanical walls in other locations. Errors like these are common. It's what happens when design problems follow the project into construction.

Contractors are skilled at following clear instructions. They are not prepared to:

  • Analyze how choices will affect long-term performance
  • Redesign building components while construction is underway
  • Assess moisture and thermal risks as a coordinated system
  • Balance structural requirements with HVAC and plumbing routing

When design questions aren't resolved before construction starts, on-site decisions get made under pressure — by people whose primary incentives are schedule and margin, not your home's long-term performance. A contractor who has to choose between a standard window that fits the schedule and the window the design called for will choose the one that keeps the crew moving.

This typically leads to:

  • Simpler details that reduce durability and long-term performance
  • Building envelope changes that affect energy efficiency and moisture control
  • Last-minute material substitutions that affect how the building performs
  • Trades interpreting the same gap in the drawings differently

Unresolved design problems also compound. A cut floor truss needs to be resolved by a structural engineer because a floor truss system is engineered. This happens whenever a floor truss blocks a plumbing fixture, such as a toilet or shower drain pipe. That plumbing drain pipe conflict can also cascade and impact the HVAC riser locations. Those risers and plenums require bulkheads, and bulkheads reduce clearance in the ceiling. This impacts the window and the trim carpenter who installs the casing above. Each individual system's resolution creates the next problem, because time wasn't taken to conduct a constructability review during the design. The homeowner pays for the time and materials needed for each resolution.

A thorough design process gives contractors clear building instructions, specific performance targets, and fewer unexpected issues — which means fewer change orders, fewer delays, and a build that proceeds the way it was intended.

Design should not be left to resolve during construction. When contractors solve design problems, homeowners pay more — immediately, and for years afterward through compromised performance, comfort, and durability.

Real-world impact

In a renovation project where structural beam placement was left unresolved at permit submission, three separate on-site decisions over six weeks resulted in $22,000 in unplanned change orders — none of which were covered under the original contract. The original design fee that would have resolved all three: $10K well invested.

What These Three Mistakes Have in Common

The same pattern runs through all three: decisions get made before the information needed to make them well is actually in place. The site isn't understood before design starts. Design decisions aren't tested before drawings are issued. Coordination isn't owned before construction begins.

Each mistake opens a gap. And each gap, left open, converts into a cost — during construction, or over the lifetime of the home.

That pattern is what TLOL's process is built to interrupt — at each of those three points, before the cost is locked in. You can see exactly how that works here: Our Workflow →