Building Science

How much moisture air can hold depends on the temperature, which is why they call it “relative humidity.” Here’s how it works and why it matters.

A radiant barrier, such as that on foil-faced rigid insulation, can reduce heat transfer across the airspace between the strapping and metal roofing and siding. Image courtesy Matt Risinger 

 

Foil blocks heat transfer best if it stays clean, is adjacent to an airspace, and the delta is large enough. 

framing with thick zips

This cold-climate wall system allows for smooth old-to-new transitions and incorporates a flush-framed deck ledger detail

professional remodeler adding a space between exterior wall and roof for efficiency

Whether you use trusses or rafters, creating space above exterior walls will improve energy performance

Tightening this complex intersection of framing materials

It's rare to find lighting guidelines backed up by documented field testing

In a tightly air-sealed house, a mechanical ventilation system ensures a healthy exchange of fresh air

computer lighting model

A computer lighting model converts input (such as ceiling and counter height, fixture and lamp type, surface color and reflectance, etc.) into both 2D output showing projected fc levels at every point on a 2x2 grid (above right), and a 3D model of the room showing the effects of the lighting plan (above). Current light levels at the island (right) are more than three times the 15 fc readings taken before the kitchen remodel.

Real-world footcandle readings shine a light on the importance of recessed fixture size, lamp type, and fixture location

Many remodelers don’t know how to talk about chemical sensitivity

When a balloon loses air or depressurizes, it gets smaller (and makes a funny sound), but houses don’t roll like that 

A hole was opened up in the soffit, but rather than encountering solid foam, small beads and dust poured out of the opening. 

How can indoor air quality become so bad when there's penty of venting and no toxic materials? 

Shingling over an old roof may be faster, cheaper, and a common practice. But some companies refuse to do it.

Tests for permeability measure vapor diffusion through a material with 50 percent RH air on one side and either a desiccant (“dry cup test”) or liquid water (“wet cup test)” on the other.

Understanding how water vapor interacts with building materials is critical to avoiding moisture problems in building assemblies

air quality EPA home

Follow these three rules for better indoor air quality in the home

Time-tested architectural elements in masonry buildings not only look good, but serve to channel water away from the walls

The New American Remodel is co-sponsored by Professional Remodeler and the National Association of Home Builders (NAHB). The home will be open for tours during the International Builders’ Show in January 2018.

Transforming a 1930s Orlando home into a showcase of contemporary living

old masonry building insulation-photo-old brick wall

Letting brick dry evenly is the key to avoiding water problems

An interior chase on an exterior wall is an often-overlooked source of major air leaks

pro trade craft fat-wall window flashing

Use wide tape to span the many layers in a thick wall for an air- and water-tight seal

An energy-minded carpenter’s take on when it makes sense to use less wood in a wall—and when it doesn’t

Photo: Dan Morrison

It may look rustic—it means ‘to flower out’ in French—but it can get ugly if it causes deterioration in brick or block

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