Renovation and build cost estimate: what are you actually paying for?
If three builders give you three very different prices, it is usually not the rates that differ — it is what each of them included. With your own itemised material list the quotes become comparable, even without a construction background.
Why it is hard to tell which quote is the good one
The quotes do not cover the same things
One includes the corner beads and fixing plugs for the insulation, another does not. The bottom lines are then not comparable, even though at first glance they look like they are.
“Materials + labour” on a single line tells you nothing
It does not show how many square metres or how many pieces the builder allowed for. If it turns out mid-job that more is needed, the extra is on you.
Asking afterwards is expensive
Once work has started, variations always cost more than the original quote. Quantities are worth settling before the contract.
What your own material list gives you
You will know the order of magnitude
Not the exact pennies, but roughly how much material is involved. That is enough for an unrealistically low or high quote to stand out.
You will have something to compare against
You can go through the quotes line by line against the list, and ask about whatever is missing from them.
In a breakdown you can follow
By material category, in plain language — masonry, insulation, screed, floor and wall finishes, roofing. Not trade jargon.
For the whole house or just part of it
You choose which material categories you care about. For a bathroom refit you do not need the roofing.
How it works, step by step
Find the drawing
The planning or construction drawing as a PDF. If you do not have it digitally, you can request it from your architect or the building authority.
Upload the floor plan
The floor plan is required; a section and a site plan make the result more precise. Processing takes 1–3 minutes.
Check the recognised data
It is worth checking the room names and sizes. If something is off, you can change it — no professional knowledge needed, just the drawing.
Download it and take it with you
Take the PDF report to your meeting with the builder and go through it item by item together.