Tuesday, February 21, 2012 at 10:51AM
Last week the Des Moines, Iowa City Council approved public incentives for two new downtown hotels that will be faced with thin brick. The decision went against the recommendation of the City’s Urban Design Review Board which had insisted on full brick despite claims by the developer that the additional cost of full brick – which he projected at $400,000 – was a deal breaker.
The controversial project raised the question among the public and city officials, “Just what is thin brick?” Let's start by discussing what thin brick is not:
- Thin brick is not an artificial product made of concrete or fiberglass masquerading as real brick. Thin brick are made from clay and are fired in a kiln just like full brick. Therefore, it’s not accurate to describe the choice as being between thin brick and “real” brick. They are both real. Non-clay, unfired products made to imitate brick, however, are not real.
- Thin brick is not the structural component of the wall, but neither is full brick in most cases. While brick can be used to hold up the loads of the building, it is much more common for brick – thin or full – to be used as a veneer applied to the outside of the load bearing structure.
- Thin brick is not significantly less expensive than full brick. Yes, thin brick is, well, thinner than full brick (less than one inch in depth) and one would therefore assume it to be much cheaper. But thin brick typically requires at least one extra step in the manufacturing process and its installation has its own cost variables. It’s also important to note that both full brick and thin brick are a relatively small part of the cost of the overall wall system.
What's the difference?
To better understand the differences between full brick and thin brick, it’s helpful to visualize how each are applied. The masonry cavity wall (below) is a time-tested wall design for the application of full brick. It calls for a gap between the structural wall and the brick façade, which is critical for managing any moisture that may find its way in. Water is channeled down the inside of the cavity and out the bottom of the wall. The cavity necessitates that brick be stacked up from the foundation, supporting its own weight, with mortar binding each unit together. The brick façade is anchored to the structural wall behind it with ties that span the cavity between.
Thin brick applications are many and varied, but a common characteristic is that they forgo the traditional wall cavity to adhere the thin brick directly to some other wall surface. Thin brick's lighter weight makes this possible, but water must be managed in some other way. Because large-scale thin brick applications are so varied, there is not yet a universal standard so proven as the cavity wall system used with full brick.
Thin brick can be adhered to the sheathing of building walls with lath and a mortar bed, usually done onsite, or can be set into pre-fabricated panels. Often made of concrete, these panels can be designed to be load-bearing or may be attached to the side of the structure as a veneer (above). The concrete approximates mortar lines between the thin brick units on the surface. Once complete and at the job site, thin brick panels install quickly with the help of machinery and can sometimes speed up construction and reduce costs. But those savings are typically only realized on very large projects with unique constraints. Thin brick often finds its way into stadiums and parking facilities for this reason (minimal interior finish demands may also play a role).
What's best for my community?
Though thin brick does a respectable job of giving the appearance of full brick, there’s nothing quite like a brick wall hand-laid from the foundation by a mason. The nature of the district in which a building is proposed should greatly impact whether thin brick is allowed as a substitute. Where charm, character, history, or authenticity is highly valued, full brick should reign. Where thin brick is deemed an aesthetically adequate substitute, the proposed wall system should be closely examined to ensure that all of the benefits provided by full brick (e.g. water management, thermal mass, impact resistance) are delivered in some other way.
Communities should also expect full brick when public funding is on the table. When taxpayers are footing part of the bill, the public should expect the developer to go the extra mile. With respect to the Des Moines hotel project, however, the public financing carrot had already been leveraged to convince the developer to alter project plans in other, more fundamental ways, leaving the brick vs. thin brick debate to rage on.
If you'd like more information about any of these issues, or about building materials in general, please contact one of our AICP planners for free assistance. 866.644.1293 or firstname.lastname@example.org.