Why Do Prices Keep Changing? Understanding Commodity Costs in Building Projects

Ever wondered why the cost of a deck, shed, or renovation project seems to change from month to month?

You’re not alone. Whether you're a homeowner starting a backyard project or a contractor pricing out materials, it's common to run into fluctuating numbers—especially for items like lumber, steel, and exterior cladding.

At North Dundas Building Supplies, we understand that unpredictable prices can be frustrating. That’s why we believe in transparency—and why we’re here to help explain why this happens and how you can better plan for it.

What Affects the Price of Building Materials?

1. Global Supply & Demand
Commodity products like lumber and steel are part of a global market. That means a shortage of raw materials in one part of the world—or a spike in demand somewhere else—can drive up prices quickly, including softwood lumber price shifts felt here in Ontario.

2. Transportation Costs & Fuel Prices
Freight and fuel costs play a big role. If diesel prices increase or trucking availability becomes tight, the cost to deliver building materials—like treated lumber, plywood, or siding—to our yard (and eventually to your job site) also rises.

3. Currency Exchange Rates
Many building materials are imported. If the Canadian dollar weakens against the U.S. dollar, we pay more for the same product—and that difference trickles down.

4. Seasonal Demand
Spring and summer are prime building seasons in Ontario. When more people are building decks, sheds, or homes, demand increases—and lumber prices today often follow.

5. Policy Changes and Tariffs
Occasionally, international tariffs or government regulations impact building material costs in Ontario. These aren't always predictable but can cause sudden price changes, especially on bulk materials and imported goods.

Why Prices Can Change So Quickly

Lumber market conditions don’t follow a fixed pricing model. Even within a few weeks, you might see a 10%–30% change in current lumber prices. That’s not a markup—it’s simply the reality of a dynamic global commodities system.

If you’re working on a project, it’s important to know that the price of lumber in Ontario you saw last month may not be valid today. This is especially true for larger purchases or custom orders.

How to Plan Your Project with Pricing in Mind

Here’s how you can stay informed and in control:

1. Request a Project Estimate
Before you start, request a free building material quotation through our website or in-store. This gives you a clear picture of current lumber prices, availability, and timelines.

2. Try Our Design & Material Takeoff Service
For more complex projects like full decks or garages, we now offer a Design & Material Takeoff Service. This gives you a professionally detailed breakdown of the materials you'll need—saving time, reducing waste, and giving you the most accurate pricing possible.

3. Build Flexibility into Your Budget
Allow some wiggle room in your budget—especially if your project will unfold over several weeks. Material prices can shift between phases, and being prepared will reduce stress and delays.

4. Talk to a Real Person
Our team is here to help. We can talk you through material options, check current stock, or even recommend substitutions if prices jump unexpectedly.

The Bottom Line

Fluctuating prices aren’t a sales trick—they’re part of a fast-moving, global materials market. At North Dundas Building Supplies, we believe in helping you understand the “why” behind the numbers.

Whether you're building a deck, planning a new shop, or starting a home upgrade, we’re here to guide you. Request a Project Estimate or ask us about our new Design & Material Takeoff Service—and plan your project with confidence.

Serving Winchester, Chesterville, Kemptville, Russell, Morrisburg, and the surrounding areas. Visit us in-store or request your estimate online at ndbs.ca/estimates.