Building Science in the Bathroom

A modern and minimalist deep bath tub in a light-filled bathroom nook. The room features pale sea-green walls and hand-painted flooring with a vine or plant-like pattern. — This warm and inviting bathroom features a hand painted concrete tile floor from Grow House Grow. The bathroom faces south creating a warm, light filled space. Wood wainscoting creates a nook for the Badeloft tub and a higher privacy wall for the shower behind. The project’s home design was done by Mottram Architecture, with interiors by Kerry Lewis, Landscape Architect. PHOTO: MICHAEL WILSON

By Tim King

OFTEN THE SMALLEST room in the house can be the most important when it comes to creating a healthy home. Here are a few ways to keep things flowing in the right direction in your bathroom.

THE VENTILATION CALCULATION

As new homes are being designed to be built tighter than ever before, the mechanical ventilation systems that are being installed in bathrooms have an increasingly important job to do.

A quality bathroom fan helps prevent mold by removing moisture associated with bathing. But it can also help exhaust other sources of “stale air” produced within the home, including the off gassing of building materials and appliances and carbon dioxide caused by human respiration.

With these important benefits in mind, it’s hard to overspend on a bathroom exhaust fan.

As a basic rule of thumb, homeowners should select a fan based on the physical dimensions of the bathroom. Exhaust fans are rated by the amount of air they can move during a set amount of time, listed as cubic feet per minute (CFM). At a minimum this number should match the size of the bathroom. For example, a typical medium-sized bathroom (8’ x 8’ or 64 square feet) would need an exhaust fan of at least 64 CFM.

However, most experts agree that more is better when selecting a new bathroom exhaust fan. That’s because it will also help pull old air from other parts of the home, encouraging better overall air circulation throughout the building.

Always remember to run the exhaust fan while using the shower and keep it running for at least 15 minutes afterward to allow the fan enough time to remove all the excess moisture from the room. Many newer model bathroom exhaust fans now either come with easy-to-use timers or moisture sensing off/on switches built in. Advances such as super quiet, multi-speed operation provide a nearly silent, low-energy method of removing old air out of an apartment or home, allowing for fresh air to enter in (naturally) through other places throughout the building.

Long-trusted, dependable brands of well performing bathroom ventilation fans include Panasonic, Broan-NuTone and Homewerks.

HOT-WATER WISE

Depending on several factors, including the size of the home and the distance that hot water must travel from where it’s heated to where it’s being used, there’s often a lag time in which cooler water is wasted right back down the drain.

Along with efforts to insulate pipes to prevent heat loss while the water is in transit through the home plumbing system, some homeowners opt to install either on-demand water heaters or high-efficiency water heaters near to where the hot water is needed. Consisting of a heating element and a highly insulated, relatively small water tank (with a capacity of 1.5 to 8 gallons), these units are typically installed either under a sink or in a closet adjacent to the tub/shower and provide nearly instant hot water, reducing the amount of water that’s usually wasted waiting for it to heat up and travel from the home furnace or hot water heater.

MICROCEMENT FOR MAXIMUM DESIGN FLEXIBILITY

Microcement is a relatively new building material that’s begun to influence bathroom (and kitchen) design. A lightweight material with a low environmental impact, microcement can be applied to existing room surfaces such as tile or wood to upgrade them without the need for demolition.

Durable and strong, with the ability to imitate more expensive marble or stone finishes, it provides an economical solution for homeowners looking to transform their kitchen or bath with less demolition waste. And because it is much lighter than marble or stone, it requires less energy to transport through the supply chain, resulting in a lower carbon footprint. Once installed, a microcement surface can last decades.

A microcement surface, made waterproof with the addition of special polymers, can be used to create sleek, contemporary bathroom walls and flooring that is easy to clean and maintain. As a shower enclosure, a thin layer of microcement can be used to create a seamless, attractive surface—with no grout lines to trap dirt or promote mold growth. The end result is also a much shallower, sloped shower tray that is essentially flush with the surrounding bathroom floor.

This shallow shower floor not only creates a step-in shower that is easier for anyone with mobility issues, it can also provide the illusion of a larger space. Depending on the finish and sealants used during installation, a microcement bathroom floor can also feature built-in anti-slip properties. Installing a new bathroom shower with a microcement base will be an attractive feature for older adults concerned with slips and falls that can occur while stepping in and out of a traditional tub or the edge of a shower stall. Microcement manufacturers include Topciment®, Luxury Concrete®, BAUTECH® and MicroCement®.