1. Beams all twist and crack. As Moisture leaves the wood, twisting and cracking can turn an attractive, decorative ceiling beam into a twisted monstrosity. Wood was all once alive, and had a very high moisture content. The wood used for building homes is all dried in a Kiln, hence names like KD Hem Fir, where KD is Kiln Dried. It is prohibitively expensive to kiln dry large beams, as the wood will twist and crack, at which point it will need to be ripped down again. The price is often 2 or times that of a regular beam.
2. Beams require a structure engineered to support them. When an architect builds a house, he may spec out coffered ceilings, large wood headers, and all manner of decorative wood beams. To support the weight of these very heavy chunks of wood, the architect will also need to design the structure in a sturdier fashion, to support the weight. This means larger and more expensive trusses, as well as more wood in the walls, more bolts, etc… Many times the desired ceiling beam span cannot be achieved without danger of sagging ceilings and trusses, a very expensive problem.
3. FOHC beams hurt the environment. FOHC – Free Of Heart Center Beams are required for beams of any size, as they are less prone to twisting (though they do still twist, just somewhat less). In order to produce these large beams, very mature trees must be used, as the beam needs to be cut from the tree without any of the heart center present. For a 12″ x 12″ x 16′ beam, very common, this requires use of trees that are 50 plus years old. Often these beams are harvested illegally in south American forests, where the removal of the trees, the habitat of many of the indigenous species, harms the eco system beyond measure. The larger the beam required, the more certain the beam was harvested illegally, in an unsustainable fashion, and with serious environmental ramifications.
4. Mold and Rot. This one is a no brainer. Even if you do not live in an arid climate, there exists great potential for the beam to become damaged. Rot and Mold can set in with any beam, devastating the appearance, and creating mold spores which are potentially hazardous to the health of you and your family.
5. Fire Safety – wood beams provide fuel to any fire in your home. With enough wood located in common areas throughout your house, a fire can spread with terrifying speed. Most building materials in your home are somewhat fire resistant, insulation, stucco, insulated wires, roof shingles, etc… even wood framed homes are fire blocked to help prevent the fire from traveling. Many fires are unable to spread fast enough to burn down homes. But this calculation is dramatically altered by the presence of large chunks of wood.
There are several alternative solutions for decorative wood ceiling beams. These products have not become as mainstream as they should due to varying quality and supply. Polyurethane beams are the most well known, and have earned a reputation for being fake looking. Even the best polyurethane beam never really looks like a piece of wood, and is a disappointing replacement for a conventional beam.
The Box Beam is the best alternative. This is a decorative beam that does not serve any structural purpose. It is made from 3 pieces of lumber glued together. As you may imagine, this is only an option for a master craftsman, a professional carpenter who is equipped for just this. This will not work for the do it yourselfer, as without perfect technique the final result will just look like pieces of wood stuck together. Done right, a box beam is indistinguishable from a real beam, seamless and without joints. It also contains blocking, which is a further way of preventing fire hazard. Since it is made from Kiln Dried Lumber, there is no possibility of a coffered ceiling made with box beams looking like a Tim Burton movie after a couple of years.