said by alkizmo:I don't know. I wouldn't see why they'd do that in renovations as the client would pay up for material.
I think it's more of a reason of condensation/moisture dissipation.
But my basement was dry as a bone all winter. Then again it wasn't being inhabited.
The building code does not distinguish between new construction and renovations - if it says you have to put R20 in (or whatever) and a vapour barrier, then that's what you've got to do, using CCMC-approved* (or provincially approved) materials according to code (unless you are doing the work without a permit or there's no permit required for the work you're doing according to your provincial building code). Technically, ripping out/replacing old insulation in Ontario *requires* a permit & inspection -- but lots of people skip that - and lots of those people don't get a proper job done as a result.
It has ZERO to do with condensation/moisture dissipation. That's what HRV/ERV's do in tightly sealed homes. The more insulating and air sealing you do to an older home, the more likely you will need to also install an HRV/ERV && to replace your furnace & hot water tank with sealed direct-vented ones which get their combustion air directly from outside.
Home owners whose homes become tightly sealed over time via renovation and DON'T replace their
a) heating appliances and
b) add an HRV/ERV
are setting themselves up for 'sick building syndrome' at best and possibly death due to carbon monoxide poisoning.
Homes are a "system" and you can't air seal/insulate and forget about what happens to atmospheric (takes combustion air from inside the home) furnaces/water heaters/stoves that use open flame combustion. Installing sealed combustion, direct vented appliances and HRV/ERV helps get you around these issues.
I have seen homes renovated by homeowners or jackass know-nothing contractors where they install a 6-burner stove and gas oven and then stick a 1500 cfm exhaust hood over the stove. The stove is going full tilt to cook a holiday meal, the exhaust hood is on, and the atmospheric furnace and water heater are spilling out CO into the basement because they are starved for air due to incomplete combustion, and backdrafting due to the kitchen exhaust hood being on. People get headaches, chronic fatigue, and disorientation when exposed to low levels of CO over time. Higher concentrations lead to death. But since the renovations were just in the kitchen & bathrooms, nobody ever looked at the house as a system.
A cottage I built has a monster kitchen exhaust hood, but when I was building it I installed a make-up air intake which was interlocked via relays and other controls to the kitchen exhaust hood. The kitchen exhaust won't turn on until the intake signals that it is open. In the winter the intake also pre-heats the incoming air via an in-line radiator connected as a zone on the boiler. Do you think that the kitchen contractor did this? No. Do you think the average homeowner would ever contemplate this? No. I spec'd it (engineer here) because the house is a SYSTEM or inputs and outputs, and life-safety considerations.
BTW, the client always pays. The only question is to whom.
*Canadian Construction Materials Centre - the national testing/approval body in Canada