Saturday, 16 February 2013


Complicated bathrooms require careful design, but as long as moisture control is accounted for during every step in the process, even the most ambitious creation can expect many years of useful service.

1.Exterior bathroom walls must be able to dry
Cold-climate wall assembly dries to the exterior In regions where interior humidity levels are typically greater than those on the outside, a vapor barrier is placed on the interior surface of the wall, while
permeable sheathings are used on the exterior.
Hot/humid-climate wall should dry to the interior
In regions where exterior humidity levels are typically greater than those on the inside, the vapour barrier goes on the outside of the wall, while permeable sheathings go on the inside.

Plumbing lines belong indoors
If plumbing lines have to be located along exterior walls, the best way to maintain an impermeable vapour barrier (and to ensure that the pipes won’t freeze) is to frame a nonstructural “water”
wall for pipes inside the exterior wall.

2.Seal all gaps to keep moisture in its place
To prevent moisture from escaping a humid bath environment and condensing within walls, floors or ceilings, every penetration should be sealed with a long- lasting, flexible sealant such as polyurethane foam.

3.Looks funky but makes sense
Placing water controls closer to the door (rather than centred on the shower head) makes them easier to use and lessens the likelihood of water escaping from the shower.

4.Keep recessed lights inside conditioned airspace
Although recessed lights that carry an IC-rating can be placed in an insulated ceiling, an airtight installation is extremely difficult to achieve. A better solution (if ceiling height permits) is to install these lights inside a soffit or a dropped ceiling.
Covering walls and ceilings with drywall before building the soffit creates an air barrier between conditioned and unconditioned spaces

5.Double-seal vulnerable joints to make sure all the water stays in the tub
The weight of a tub full of water puts great stress on caulked joints. If the tub unit does not have a lip that extends up the wall, use 50-year silicone sealant to caulk the joint where the backer-board meets the tub, as well as the joint where tile meets tub.

6.A little bit of lip keeps water in its place
A solid-surface vanity top that combines basin, counter and backsplash in one seamless unit is leak- proof but creatively limiting. Substituting a 1⁄2-in. tall cove for a full backsplash still contains water splashes yet allows clients to trim the vanity top with a variety of materials, such as tile or mirrors.

7.Don’t just dump it in the attic
The necessary components of an effective bathroom exhaust system include a high-quality, quiet fan unit, and a short run of insulated ducting that directs water vapour out of the house before it’s able to condense.

The installation of a ventilation system is critical. The duct system should take the shortest, most direct route to the outside; but even a short run of ductwork can be troublesome. To prevent trapped condensation, I use insulated, rigid pipe, and I make sure that the pipe has a slight pitch, either to the outside or back to the fan.
In tight, modern houses, an adequate supply of return air must be provided in conjunction with the ventilation. This can be as simple as making sure there is at least an inch of air-space under the entry door or as complicated as providing a passive makeup-air duct.
Even if it’s perfectly installed, an exhaust system won’t get the job done unless it is used. I strongly recommend to my clients that they leave the fan running—with the door closed to make sure moisture cannot escape into neighbouring rooms—for at least 30 minutes after taking a shower or using a whirlpool. Placing the ventilation fan on a timer makes following this advice easy. An even easier solution is to connect the fan to a humidistate that will automatically turn the fan on and off according to the humidity levels.

Foolproof switch guarantees fan is used
This programmable timer-switch ensures that the fan runs
long enough and often enough to clear the air.

Baths need regular maintenance
After eliminating unnecessary moisture problems, constant vigilance is the key to maintaining a dry bathroom. Indoor air humidity and temperature must be controlled through-out the home. What might be a comfortable condition for the homeowner might not be ideal for the home. Relative humidity be- tween 40% (winter, generally) and 65% (summer), with a constant temperature around 68°F, is best. Frequently inspect visible caulk joints and redo them when they first show signs of degrading. At least a few times a year, get a good flashlight and summon the courage to poke around in the basement, crawlspaces and attic, looking for any signs of moisture leaks, musty odours or nasty bugs.