Costing Out a House I Haven't Built Yet

TL;DR

• Plan is to build as economically as possible, leaning on my dad and my partner’s brother for the experience I lack.
• Salvage is central: monitoring Marketplace and Kijiji, and needing a trailer and a 20-foot container to store it.
• Building on our existing property beats buying, even though the town isn’t ideal.
• Costing method: perimeter of a 1,500 sq ft plan × material cost per foot for each wall assembly.
• Comparing 2x4, 2x6, SIP panels and block walls up to sheathing, excluding common elements like drywall.

Thinking seriously about building a home as cheaply as we can do it properly.

What I’m working with

I don’t have direct experience, so the plan leans on family who do — my dad and my partner’s brother. Material costs are volatile enough that the technique choice matters more than usual, and block walls look cost-effective if labour-intensive. Doing most of the work myself is the point, building on what I learned from past DIY renovations.

Funding could come from a promotion in my current role, or from selling this property to finance a new build or a turnkey purchase. But building on land we already own stretches the budget furthest, especially spread over three years with salvage and careful spending.

Why here, despite the town

Our town isn’t ideal, and building here still wins. Staying put means we save enough to spend it on experiences for the kids — exposure to more vibrant places than the one we live in. That’s a better trade than buying into a nicer town and having nothing left over.

There’s also the part that doesn’t show up in a budget: after years of living on this property, we understand its landscape and ecosystem. Where the water goes, where the sun falls, which trees matter. That knowledge only comes from time, and it’s worth something when siting a house.

Salvage as strategy

Salvage isn’t a nice-to-have here, it’s the mechanism. I’m monitoring Facebook Marketplace and Kijiji, which means being ready to collect at short notice.

That needs infrastructure. A utility trailer for transport, and a 20-foot shipping container for storage — because materials acquired over three years have to live somewhere dry in the meantime. Buying storage to enable free materials is a real cost, and it still comes out ahead.

Two-by-fours are the focus, since they turn up constantly at minimal or no cost.

The costing method

This is the part I actually worked out today.

Start with the perimeter of a 1,500 square foot home — it took a couple of attempts to get right. Walking through floor plans against real site conditions matters here: preserving particular trees, avoiding bedrock. The site constrains the shape before any aesthetic preference does.

Then build an assembly for each construction technique — 2x4, 2x6, SIP panels, block — covering everything up to sheathing and excluding common elements like drywall that don’t vary between methods. Reduce each to a cost per foot using standard material sizes.

Perimeter × cost per foot gives a comparable number for each technique against each floor plan. It ignores wastage, so the real figures will be higher, but it’s the reality check I needed on what these choices actually cost.

The goal is a build that’s cheap, structurally sound and environmentally considerate. Establishing which techniques are affordable is what makes the rest of the planning meaningful rather than aspirational.