Finishing a basement without redoing it in five years.
Before finishing a basement, three things have to be checked: the condition of the French drain, the presence of an infiltration or an active crack, and the headroom under the beam. A finish laid over a moisture problem gets demolished within five years on average. The preliminary diagnosis costs a fraction of the price of the do-over.
The three preliminary checks
The French drain. Its useful life is counted in decades, not centuries. On a house from the seventies or eighties that has never had it replaced, it's approaching or past the end of its life. A clogged or collapsed drain doesn't show every year: it shows in the wettest spring.
Cracks. Not all are active, and not all are serious. What matters is knowing whether it moves and whether it lets water through. A crack that widens from one year to the next is a signal, not a cosmetic detail.
Headroom. Measured under the beam and under the ducts, not at the highest point of the room. That's the height that will determine whether the finished space is comfortable or merely usable.
When headroom is lacking
Three options, in order of cost.
Reorganizing the mechanics. Grouping ducts and pipes in a bulkhead at a strategic spot rather than letting them cross the room. It doesn't gain height everywhere, but it gains it where people live.
Reducing the thickness of the finished floor. Some subfloor systems gain a few inches over a traditional build-up.
Lowering the slab. It's structural work: the slab and the footings are reworked together, it requires sealed plans, and it's by far the most expensive option. It's justified when the gain in living space far exceeds the investment.
Insulation and vapour barrier
A poorly insulated basement isn't just cold, it condenses. The warm, humid air of the house meets a cold surface, and water appears where nobody sees it, between the insulation and the concrete.
The assembly has to respect the current code: type of insulation, position of the vapour barrier, clearance from the foundation wall. These are details that are invisible once the drywall is up, and they're what determines whether the basement stays healthy.
Adding a bathroom in the basement
It's the most frequent request and the one that changes the cost of the project the most.
The deciding point is the position of the drain relative to the sewer outlet. When it's lower, you either break the slab to connect by gravity, or install a lift station. Both solutions work, but they don't have the same cost or the same maintenance constraints.
Ventilation is the second point. A basement bathroom needs an exhaust to the outside, never into the attic or the crawl space.
The signs that drainage has to be redone first
A musty smell that comes back in spring. White efflorescence on the concrete. Paint blistering at the bottom of the walls. An old finished basement whose lower walls have already been repaired once. A lot whose grade brings water back toward the house.
None of these signs is a catastrophe. They all mean the same thing: you have to look before you finish.
So, what are we working on?
Eight questions, two minutes. We call you back to talk it through, and we tell you frankly whether it's a project for us or whether you'd be better served elsewhere.