---
title: "Guides to Building and Renovating in Ontario"
url: "https://www.jarviscontracting.ca/guides"
description: "Guides for Durham and GTA homeowners on what building and renovating cost, which permits apply, additional residential units, and how design-build works."
publisher: "Jarvis Contracting"
---
# Guides to Building and Renovating in Ontario

Guides for Durham and GTA homeowners on what building and renovating cost, which permits apply, additional residential units, and how design-build works.

- [Design-build or architect plus contractor in Ontario?](https://www.jarviscontracting.ca/guides/design-build-vs-general-contractor) (2026-10-05): Design-build or an architect plus a general contractor for an Ontario addition: who carries the risk, who files the permit, and why the 10% holdback applies.
- [Do you need a permit to finish a basement in Durham Region?](https://www.jarviscontracting.ca/guides/basement-permits-durham-region) (2026-10-05): Yes. Every Durham Region town needs a permit to finish a basement: about $356 to $693 for 700 sq ft at 2026 rates, plus a $1,000 deposit in Pickering.
- [Fixed price vs cost-plus contracts for Ontario renovations](https://www.jarviscontracting.ca/guides/fixed-price-vs-cost-plus) (2026-10-05): Fixed price or cost-plus for an Ontario renovation or addition: how each prices risk, the 10% estimate rule, deposits, holdbacks and what to put in writing.
- [HCRA licence and Tarion warranty: who needs them in Ontario](https://www.jarviscontracting.ca/guides/hcra-and-tarion-explained) (2026-10-05): New Ontario homes need an HCRA-licensed builder and Tarion's warranty, up to $400,000. Renovations and additions don't. Here's where the line falls.
- [How many units can I add to my lot in Ontario?](https://www.jarviscontracting.ca/guides/bill-23-additional-units-ontario) (2026-10-05): Bill 23 lets you have three units on most serviced Ontario lots, and Whitby, Ajax and parts of the GTA allow four. Compare Durham Region and GTA town rules.
- [How much does a home addition cost in Ontario in 2026?](https://www.jarviscontracting.ca/guides/home-addition-cost-ontario) (2026-10-05): We price home additions at $350 to $600 a sq ft in 2026, and a 300 to 700 sq ft rear addition at $180,000 to $450,000. Durham permit fees, worked out.
- [How much does a second-storey addition cost in Ontario in 2026?](https://www.jarviscontracting.ca/guides/second-storey-addition-cost-ontario) (2026-10-05): Our 2026 range for a 600 to 1,200 sq ft second storey is $300,000 to $800,000 before HST. What quotes leave out, plus Durham Region permit fees by town.
- [Is it cheaper to build up or out? 2026 Ontario costs](https://www.jarviscontracting.ca/guides/build-up-or-out) (2026-10-05): Our 2026 ranges: $300,000 to $800,000 to build up a storey, $180,000 to $450,000 for a rear addition. Your lot decides: Durham height and coverage limits.
- [Ontario HST relief for owner-built homes and big renovations, 2026](https://www.jarviscontracting.ca/guides/ontario-hst-relief-substantial-renovation) (2026-10-05): Ontario's 2026 to 2027 HST relief can return up to $130,000 on an owner-built home or substantial renovation started by 31 March 2027. Here's the test.
- [Questions to ask a contractor in Ontario before you sign](https://www.jarviscontracting.ca/guides/questions-to-ask-a-contractor) (2026-10-05): Questions to ask an Ontario renovation contractor before you sign: permits, WSIB clearance, insurance, licences, a 10% deposit cap, holdbacks and cooling-off.
- [Should we add on or move? Costs compared for 2026](https://www.jarviscontracting.ca/guides/renovate-or-move) (2026-10-05): Moving to a $1,200,000 home in Durham costs $20,475 in land transfer tax, and $40,950 in Toronto, before commission. How that stacks up against an addition.
- [What does a legal basement apartment cost in Ontario in 2026?](https://www.jarviscontracting.ca/guides/legal-basement-apartment-cost-ontario) (2026-10-05): We price a legal basement apartment at $80,000 to $180,000 in 2026, or $45,000 to $95,000 to legalise a finished one, plus Durham fees and a tax credit.
- [What does a legal basement apartment need in Ontario?](https://www.jarviscontracting.ca/guides/legal-basement-apartment-requirements-ontario) (2026-10-05): A legal basement apartment in Ontario needs 1.95 m ceilings, a fire separation, egress windows and linked smoke alarms, plus your Durham town's zoning rules.
- [Whitby's ADU incentive: fees refunded for applications by 31 Dec 2026](https://www.jarviscontracting.ca/guides/whitby-adu-incentive) (2026-10-05): Whitby refunds additional dwelling unit permit fees for complete applications by 31 December 2026. The rules: 75 m², 4.5 m, $268 to register, the designs.