Table of Contents

• Introduction

• Why Estimates Matter More Than Ever

• Mistake #1: Guessing Instead of Calculating

• Mistake #2: Using Outdated Price Lists

• Mistake #3: Forgetting Hidden Costs

• Mistake #4: Ignoring Waste and Contingency

• Mistake #5: Skipping the Site Visit

• Mistake #6: Copy-Paste Syndrome

• Mistake #7: Not Accounting for Labour Fluctuations

• Mistake #8: Poor Communication with Suppliers

• Mistake #9: Lack of Review and Quality Checks

• Mistake #10: Underquoting to Win the Job

• Pro Tips to Improve Accuracy

• Smart Tools to Avoid These Mistakes

• Final Thoughts

• FAQs

Introduction

Let’s face it—estimating is the heartbeat of every successful building merchant’s workflow. If your numbers are off, your profit takes a hit. Worse? You lose trust, time, and sometimes even clients.

And in 2025, when everything moves at lightning speed, small estimating errors can snowball into big business problems.

But don’t worry—this guide is here to help you dodge those costly traps. We’ll unpack the most common estimating mistakes building merchants make, explain why they hurt, and show you how to avoid them like a pro.

Let’s dive in.

Why Estimates Matter More Than Ever

In a world driven by tight deadlines, tighter budgets, and rising material costs, Estimates for Building Merchants have become more than just a ballpark figure—they’re your first impression, your negotiation tool, and your profit calculator.

If your estimate isn’t solid, you could be:

• Losing money on underpriced quotes

• Scaring clients off with inflated numbers

• Creating delays due to misjudged timelines

• Causing project chaos due to poor planning

Ready to sharpen those estimates? Let’s call out the biggest blunders first.

Mistake #1: Guessing Instead of Calculating

We get it—sometimes you just feel like you know what the cost should be. But gut instinct doesn’t pay the bills.

Why it Hurts

Guessing leads to inconsistent pricing, missed costs, and unfair quoting. That’s a recipe for mistrust.

What to Do Instead

Use a detailed estimating sheet or software. Break down every element—from screws to skips.

Mistake #2: Using Outdated Price Lists

Material prices change. Fast. That 2023 price for timber? It’s history.

Why it Hurts

You risk underquoting and eating the cost difference—or worse, losing the client because the final bill is higher than expected.

What to Do Instead

Update your supplier price lists weekly or use software that syncs with live data.

Mistake #3: Forgetting Hidden Costs

You remember the bricks and blocks—but what about delivery fees? Tool hire? Permit fees?

Why it Hurts

These extras can add hundreds—or thousands—to a job. Miss them, and you’re out of pocket.

What to Do Instead

Use a comprehensive checklist. Never skip logistics, admin, or handling costs.

Mistake #4: Ignoring Waste and Contingency

No job is 100% smooth. Breakages, miscalculations, weather delays—they all eat into your margins.

Why it Hurts

You’ll end up ordering extra mid-project (which is pricier and delayed), or worse—delivering short.

What to Do Instead

Add 5–15% to your material totals to cover waste. Factor in contingency days for delivery.

Mistake #5: Skipping the Site Visit

Quoting a project without seeing the site? That’s like buying a house without viewing it.

Why it Hurts

You miss ground conditions, access issues, layout quirks—all of which affect cost and time.

What to Do Instead

Visit the site. Take photos. Talk to the client. Understand the space before you estimate.

Mistake #6: Copy-Paste Syndrome

Tempted to recycle an old estimate? Be careful—it could come back to bite you.

Why it Hurts

Every project is unique. Reusing old quotes without checking can lead to massive oversights.

What to Do Instead

Use templates—but adjust each quote based on current specs, scope, and prices.

Mistake #7: Not Accounting for Labour Fluctuations

Labour costs vary based on availability, region, and project scope. Ignore that, and your estimate’s toast.

Why it Hurts

Too low, and you’ll either lose your margin or deliver late. Too high, and you’ll price yourself out.

What to Do Instead

Use region-specific labour rates and account for overtime, training, or subcontracting costs.

Mistake #8: Poor Communication with Suppliers

When’s the last time you confirmed stock availability before quoting?

Why it Hurts

If you estimate based on materials that are out of stock, your whole project can derail.

What to Do Instead

Check lead times, delivery fees, and availability before finalizing any estimate.

Mistake #9: Lack of Review and Quality Checks

Even experienced merchants make mistakes. That’s why checks matter.

Why it Hurts

One typo in quantity or decimal can change the whole budget. Clients notice these things.

What to Do Instead

Have someone else review your estimate—or at least double-check your figures before sending.

Mistake #10: Underquoting to Win the Job

Look, we get the temptation. But quoting low to get the job and then adding extras later? That’s a fast track to a ruined rep.

Why it Hurts

You may win the job—but you’ll lose your profit, your time, and maybe your client’s trust.

What to Do Instead

Be transparent. Offer tiered options (basic, mid, premium) and clearly explain each cost.

Pro Tips to Improve Accuracy

Want to take your quotes from decent to unbeatable? Here’s how:

Break Down Costs

Split estimates into labor, materials, logistics, and admin. It helps you (and your client) see where the money goes.

Use Local Market Data

Don’t use national averages—use local figures. They’re more accurate and relevant.

Add a Validity Period

Prices change. Add “valid for 14 days” or similar to protect yourself.

Smart Tools to Avoid These Mistakes

Other Handy Estimating Aids

Final Thoughts

Mistakes happen. But when it comes to estimates for building merchants, avoiding them isn’t just about saving face—it’s about saving money, time, and relationships.

In 2025, accuracy, transparency, and speed are your superpowers. With the right mindset and tools, you can quote with confidence, win more jobs, and build a reputation that lasts.

So ditch the guesswork. Say goodbye to outdated lists. And let your next estimate be your best one yet.

FAQs

1. How often should I update my pricing sheets?

At least weekly. Prices fluctuate quickly, especially in construction. Better yet, use software with live supplier sync.

2. What’s a good waste margin to include in my estimates?

Between 5–15%, depending on the project. High-risk jobs may need even more.

3. Can I use the same estimate template for every job?

Yes, but always customize it. No two jobs are exactly alike, and copy-paste errors are common.

4. How do I explain estimate changes to a client?

Be honest. Use clear breakdowns and show which prices or scope elements have shifted.

5. Should I include a deadline for estimate approval?

Absolutely. Adding a “valid until” date protects you from cost increases and supply changes.