Last updated: May 8, 2026
In British Columbia, we do not just build houses. We build umbrellas that people happen to live in.
I have seen a lot of guys come up from the south or move from the prairies thinking they can apply the same fast-and-dry rules here. They cannot. In this climate, if you skip a detail to save twenty minutes, the sky will send you a bill for five grand two years later.
The quick answer
Never trust the look of a finished wall. The most important parts of your house are the ones you cannot see once the siding is on.
If your flashing is not layered like shingles and your rain screen is not breathing, you are not building a wall. You are building a sponge.
Human Salt: The Friday Rush Disaster
I remember a job site on the Island where a crew was racing to finish a cedar siding install before a massive November storm rolled in.
They were buttoning up the window trim, and I saw the lead hand skip the head flashing because “the overhang was deep enough.” He figured the porch roof would keep the water away.
He saved about 15 minutes of work and about $20 in materials.
Two winters later, I got a call to look at a soft spot under that same window. Because the wind on the coast does not just fall, it blows sideways and up, the water had been driven right into the top of that window frame.
Without that $20 piece of flashing, the water sat against the sheathing. By the time they saw the bubble in the interior paint, the structural studs were the consistency of wet oatmeal.
The repair bill for the rot, the mold remediation, and the new siding was just over $5,000.
The mistake people make
They think waterproof means tight.
They caulk every gap until the house cannot breathe. In BC, you do not try to stop the water completely. You manage it. You give it a clear, gravitational path to get out.
The better move
- Follow the shingle rule. Everything must overlap. The top layer always goes over the bottom layer. Reverse-lapped building wrap is a future repair bill.
- Respect the rain screen. In BC, that gap between your wrap and siding lets air circulate and moisture dry.
- Treat flashing like king. Do not rely on caulk. Caulk fails. Metal flashing and good peel-and-stick tape are what stand up to a 48-hour Island soak.
- Remember the wind factor. Coastal rain moves sideways. Overhangs are only a suggestion to the wind.
Watch the line
If a contractor tells you they can save money by skipping the rain screen or using a cheap wrap that is not right for our humidity, show them the door.
They are not saving you money. They are deferred-financing a disaster.
Homer’s bottom line
You can cheat a building inspector, and you can cheat a timeline, but you cannot cheat the clouds.
Do it right the first time, or get ready to pay the BC Rain Tax in three years.
Doing it right means having the right permit and the right plan. Use the BC Permit Reality Check before you start your next job.
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