Guides
Caulking and sealing tubs, showers and windows in Calgary's dry climate
Caulking is a small job that protects a lot of house. A bead of sealant around a tub keeps shower water out of the wall. A bead around a window frame keeps rain and melting snow from running behind the siding. When caulk fails, the damage it causes happens out of sight, and it is far more expensive to fix than the caulk ever was.
Calgary is hard on caulk. Dry air, intense sun at high altitude and repeated freeze-thaw cycles all age it faster than in milder places. This guide covers where caulking matters in a Calgary home, how to tell when it has failed, which products suit which jobs, and when exterior caulking can be done in this climate.
Why caulk fails faster in Calgary
- Freeze-thaw cycles. Chinooks bring repeated melts and refreezes through the winter. Water that gets into a small crack freezes and widens it. See what chinooks do to your house.
- UV exposure. Calgary sits over a thousand metres above sea level and gets a lot of sun. UV breaks down exterior sealants, especially on south- and west-facing walls.
- Dry air and movement. Wood trim, siding and window frames shrink and swell with temperature and humidity. Caulk has to stretch and compress with them. Cheaper caulks harden and crack when they cannot keep up.
- Steam and hard water indoors. In bathrooms, daily steam, cleaning products and Calgary's hard water mineral deposits wear on tub and shower caulk.
Where caulking matters inside
Tubs and showers
The joint where a tub or shower base meets the tile or surround is the most important indoor caulk joint in the house. It moves every time someone steps in the tub, and it is wet every day.
Signs it needs redoing:
- Black or pink mildew under the surface that does not clean off
- Gaps at the corners or along the tub edge
- Caulk peeling away from one side
- Cracked or missing grout at the base, sometimes with loose tiles
The fix is to remove all the old caulk, clean and dry the joint completely, and run a new bead of a mildew-resistant, kitchen-and-bath silicone or hybrid sealant. A full tub caulk needs curing time before the shower is used; the product label sets it, and it is often a full day.
Sinks, vanities and backsplashes
The joint between a countertop and backsplash, around an undermount or drop-in sink, and where a vanity top meets the wall. These keep splashes out of the cabinet below.
Toilets
Many toilets are caulked around the base. Practices vary; some leave a small gap at the back so a leak shows instead of hiding. Either way, caulk at the base is not a fix for a toilet that rocks.
Interior trim and baseboards
Painter's caulk fills gaps between trim and walls before painting. In Calgary, those gaps often open up in winter as the trim shrinks in dry air. A flexible paintable caulk handles that movement better.
Where caulking matters outside
Windows
Where the window frame meets the siding, stucco or trim. This is one of the most important exterior joints, since water that gets behind it can reach the wall structure. Look for cracks, gaps and caulk pulling away, especially on corners and at the bottom of the frame.
Exterior doors
Around the door frame and where the threshold meets the sill.
Penetrations
Dryer vents, exhaust hoods, hose bibs, cable and phone lines, exterior light fixtures and any other place something passes through the wall.
Trim joints and corners
Where trim boards meet each other, and where trim meets siding.
Some joints should not be caulked, such as weep holes at the bottom of window frames and certain siding laps designed to let water drain out. Sealing those traps water. If unsure, leave it to someone who knows the system.
How a proper re-caulk is done
Good caulking is mostly preparation:
- Remove all the old caulk. Cut it out with a blade or caulk remover. New caulk does not bond well to old caulk.
- Clean the joint. Remove soap scum, mildew and residue. In bathrooms, a mildew cleaner followed by rubbing alcohol works well.
- Dry it completely. Joints at tubs and showers need time to dry out, sometimes hours.
- Mask if needed, for a clean line on visible joints.
- Fill large gaps with backer rod first.
- Run a steady bead and tool it smooth.
- Leave it to cure for the time on the label before water or paint.
At a tub, some installers fill the tub with water before caulking so the joint is caulked at its widest point. Done this way, the caulk is less likely to tear when the tub is full.
Choosing the right product
- Tubs and showers: 100 percent silicone or a kitchen-and-bath hybrid with mildew resistance. Silicone is not paintable.
- Interior trim before painting: paintable acrylic latex caulk, ideally a siliconized or elastomeric one that stays flexible.
- Exterior windows and doors: an exterior-rated sealant suited to the materials, such as a hybrid polymer or polyurethane. Check the label for UV resistance, movement capability and the minimum application temperature.
- Large gaps: backer rod first, then sealant. Caulk is not a gap filler for wide openings.
When exterior caulking can be done in Calgary
Most exterior sealants list a minimum application temperature, and they need the joint to be clean and dry. Many also need several hours before rain. In Calgary, that usually means:
- Best: late spring through early fall, on a dry day
- Possible: mild days in late fall or early spring, if the label allows and the joint is dry
- Avoid: frozen surfaces, wet joints, or days with rain on the way
That window is short, which is why exterior caulking often gets done alongside exterior painting and the fall handyman checklist.
Indoor caulking can be done any time of year.
Caulking and draft-proofing go together
A lot of drafts come from gaps that caulk or weatherstripping can close. See the weatherstripping and draft-proofing guide.
What to send for a quote
- A wide photo of the tub, shower, window or door
- Close photos of the failing caulk
- How many windows or fixtures need doing
- Which side of the house, for exterior joints
Kaur Handyman does indoor and outdoor caulking across Calgary and the surrounding towns. See the services list.
Text a photo of the joint
Send a photo of the job, your neighbourhood and the days that suit you. You get a price back before anything is booked. Materials are agreed in the quote, and you can pay by Interac e-Transfer, cash or bank draft.
647‑806‑8070Calgary NW, NE, SW and SE, plus Airdrie and Chestermere.
Questions
How often should I re-caulk my tub?
When you see mildew under the caulk, gaps or peeling. In a busy bathroom that may be every few years.
Can exterior caulking be done in winter in Calgary?
Only if the product label allows the temperature and the joint is clean and dry. In practice, late spring to early fall is the reliable window.
Can I just caulk over the old caulk?
It rarely lasts. New caulk does not bond well to old caulk or to mildew. Removing the old bead first gives a lasting seal.
How long before I can use the shower after re-caulking?
It depends on the product. The label sets the cure time, and it is often a full day.
Why does the caulk on my trim crack every winter?
Calgary's dry winter air shrinks wood trim. A flexible, paintable caulk handles that movement better than a basic one.