Blog – Construction Drying

Keeping Construction Sites Dry – Dehumidification is the Hot Topic, not Heat

Over the course of a construction project, moisture and humidity create delays and product material issues. Old school solutions point to heat as the answer to control moisture. Others feel that fans placed inside, circulating air, will do the trick. However, these methods do nothing to actively remove moisture. Dehumidification is the key to controlling moisture, truly drying building materials, like wood and taping mud, while keeping the interior environment free of microbial growth.

Challenges on a Construction Site 

Why are moisture and temperature such a concern during a project's life cycle? Consider a building during the phases of construction.  The entire structure is open to the elements for a long period of time. Slowly, the building closes up.  During those stages, the interior structure, and all of the interior building materials are exposed to the elements, such as rain and the sun. If materials are wet from rain or there is high humidity in the building, are they being properly acclimated before installation and does it matter? Yes. For example, when floor coverings are installed without proper climate control or on a slab that does not meet specifications, cracking, popping and cupping can occur. Temporary climate control equipment could help prevent that.  So how do you prevent these issues?

Controlling Moisture and Climate

When attempting to combat moisture and control the interior of a construction project, simply using fans or relying on ‘good weather will not solve anything. Sadly, some contractors feel that they can overcome dramatic changes in temperature and humidity by circulating air or opening windows. Construction fans pulling outside air may help workers cool down or feel better, however, this tactic is not effective for controlling humidity, meeting building material specifications, or accelerating drying. 

Heat makes it Hot, Not Dry

A popular piece of equipment on construction sites each fall is the direct-fired (open flame) heater. These small, portable and seemingly inexpensive heaters sprinkled across floors are commonplace. Why do contractors routinely rent these heaters?  They do deliver heat, yes.  They are relatively inexpensive (more on that later), yes. They are easily moved across a construction site and they’re not too large.  Sounds great, right?  If you’re looking for heat and not worried about moisture or anything else, they serve a purpose, yes. 

However, not all heaters are the same, especially when comparing direct-fired versus indirect-fired heaters.  The open flame heaters discussed above are delivering heat, but at what expense? To simply introduce heat into a building space will not remove the actual moisture that is present in the air. On a construction site, the heat is welcome but moisture created through combustion, usually not.  Contractors may not be aware of the trade-off here, delivering heat but also adding moisture. In certain environments, this may not be problematic but in a damp climate, adding more moisture can become rather troublesome. 

Construction Sites and Indirect Fired Heaters

Indirect-fired heaters are the preferred heater for many projects due to their ability to deliver hot air without the added moisture.  With these heaters, the air does not cross the flame, rather it is heated indirectly (hence their name) and does not pull the moisture from the fuel source. Because these heaters are more complex in their engineering, they tend to be more expensive to rent compared to the direct-fired heaters, but they’re also capable of delivering higher BTUs and heating a larger space than a standard-sized open flame heater. If moisture is already a problem, or a project is concerned about the interior conditions, indirect-fired heaters are a path to explore. With either direct or indirect-fired heaters, they both deliver warm air but when it comes to drying, there is only one type of equipment: the dehumidifier. 

Drying a Construction Project with a Dehumidifier

Science proves that a heater does not dry materials or remove moisture. Dehumidification is the one true option to lower humidity and control moisture. A dehumidifier will both help acclimate the space and lower the moisture content of materials (flooring, woodwork, drywall).  Dehumidification, used in conjunction with fans to circulate dry air will pull moisture from materials, such as taping mud, as well as lower the overall amount of moisture in the space.  Drywall taping and mudding, millwork acclimatization, and later painting is one big reason that dehumidification and climate control has become a regular tool during interior finishing on construction sites. 

A Rental Dehumidifier is cheaper than you think

A common rebuttal from contractors is that a dehumidifier is too expensive.  In comparison, consider the cost of those direct- heaters mentioned earlier.  As stated, construction sites are usually dotted with several direct-fired heaters, all attached to large fuel tanks.  Add up the number of heaters, consider the monthly or seasonal costs for rental, and then factor in the fuel costs.  Now consider how many of those heaters can be replaced with one 5,000 CFM desiccant dehumidifier running on propane or natural gas (yes, a dehumidifier can operate on minimal electricity and propane/NG).  

A rental desiccant dehumidifier will both control relative humidity and warm space, great in fall and winter. Ultimately, if moisture management is a concern, a dehumidifier is the only type of equipment to consider. 

To understand how a dehumidifier can help you, or to examine the cost differential between using heaters or dehumidification on your project, contact your local Polygon representative

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