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Straight answers
The questions people ask most about starting and running a waterproofing business in Ontario. Answered straight, with links to the official sources.
It can be a strong one, especially foundation repair: wet basements are an emergency, homeowners buy directly and urgently, margins are good, and demand doesn't evaporate in a downturn (water doesn't care about the economy). The catch is the long-tail liability — failures surface years later — so it rewards operators who do it right and document everything.
Foundation/below-grade work — especially wet-basement repair — is the accessible, homeowner-direct, high-margin lane with emergency demand. Commercial restoration (parking garages, balconies, envelopes) is engineered, spec-driven, higher-value work for property managers and consultants. Many start in residential foundation repair (faster cash, direct customers) and move toward commercial restoration for bigger contracts.
Because waterproofing is really a diagnosis business wearing an application uniform. Most failures and most callbacks come from misreading where water is coming from and which system the situation needs. The contractors who understand drainage, hydrostatic pressure, vapour, and building envelopes solve problems permanently — and command premium prices — while the ones who just slap on product chase callbacks forever.
Two ways: do it right (proper diagnosis, the correct system, manufacturer-spec installation) and protect yourself on paper. Keep completed-operations coverage active (claims can arrive years later), document the conditions and your recommendations, and be honest about what a given repair will and won't solve. The waterproofers who get burned over-promised and under-documented.
No provincial trade licence — but you need a business licence, WSIB, and insurance, and excavation work triggers Ontario One Call locates. Manufacturer applicator certifications are the credential that matters: they're what let you install warrantied systems, which is where the commercial and higher-value work lives.
Build experience on foundation/restoration crews, get manufacturer applicator certified, and carry strong liability insurance with completed-operations. Foundation repair is the common entry — low equipment needs, direct-to-homeowner emergency demand, and high margins — and you build toward commercial restoration as you add capability and references. Building-science competence is your best marketing.
No provincial trade licence is required — waterproofing is non-compulsory. You need a business licence, insurance, WSIB, and permits where the work is structural or involves excavation. Manufacturer applicator certifications are what unlock warrantied commercial systems.
Because waterproofing failures cause water damage that can appear years later, completed-operations coverage within your Commercial General Liability is essential. Carry at least $2M CGL and confirm there is no exclusion for water damage or your core service.
A sole proprietorship is cheaper and simpler to start, but you are personally liable for the business's debts and claims. Incorporating creates a separate legal entity that limits personal liability, can reduce tax once you are profitable, and reads as more credible to larger clients. Most contractors incorporate once they have employees, real revenue, or work on others' property.
Yes — construction is a mandatory WSIB sector in Ontario. Even independent operators and partners with no employees generally must register, and clients and general contractors will require a valid WSIB clearance certificate before you can work on their site.
You must register for and charge HST once your revenue exceeds $30,000 over four consecutive quarters. Many contractors register before that threshold so they can claim input tax credits on tools, materials, and vehicles from day one.
Ontario's Construction Act sets the rules: a 10% holdback on most contracts, prompt-payment timelines (you must be paid within set periods after a proper invoice), and an adjudication process for disputes. Understanding holdback, lien rights, and prompt payment is essential to protecting your cash flow.