Over the course of the year moisture and humidity create delays and product issues on construction sites. Many contractors believe that heat is the answer to control moisture. Others feel that fans placed inside, circulating air, will do the trick. Another key group understands that dehumidification is the key to controlling moisture, truly drying products and the interior environment of a construction site.
Challenges on a Construction Site
Why is moisture, temperature and climate such a concern during construction? 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 begins to close up during phases of construction and is eventually fully enclosed. During those stages, the interior structure, and all of the interior materials used, are exposed to natural elements, such as rain, sun, and temperature. If building materials are wet from rain or high humidity, are they dried and acclimated before installation and does it matter? Yes. For example, when flooring is installed without proper climate control or without having been dried thoroughly, this is why cracking, popping and disjointed woodwork occurs in some instances. Climate control 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 or humidity by circulating air or opening windows. Construction fans pulling outside air and circulating breezes throughout the building may help workers cool down or feel better. This tactic is not effective for controlling humidity and surely not the answer to controlling the interior climate.
Heat makes it Hot, Not Dry
A popular appearance on construction sites each fall is the 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.
Not all heaters are the same, especially when comparing open flame heaters and indirect fired. The open flame heaters discussed above are delivering heat, but at what expense? These heaters deliver heat by sending air across on open flame that delivers the warmth desired. The issue becomes the open flame and how it also releases moisture into the air. On a construction site, the heat is welcome but moisture, 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 flame of the fuel source. Because these heaters are more complex in their engineering, they tend to be more expensive to rent compared to an open flame heater, but they’re also capable of delivering higher btu’s 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 the option to choose. With either open flame or indirect fired heaters, they both deliver warm air but when it comes to drying, there is only one type of equipment to effectively dry a room or building: the dehumidifier.
Drying a Construction Project with a Dehumidifier
Science proves that a heater does not dry materials or remove moisture, it may feel that way but it isn’t happening (psychrometric charts illustrate this fact). Dehumidification is the one true option to lower humidity and control moisture. As discussed above, when building materials are full of moisture and need to be dried before installation, a heater will not actually dry. A dehumidifier will both help acclimate the space and lower the moisture content of materials (flooring, wood work, drywall). Dehumidification, used in conjunction with fans to circulate dry air will pull moisture from materials, such as drywall, as well as lower the amount of moisture in the space. Drywall taping, mudding, 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 refrain from contractors is that a dehumidifier is expensive. In comparison, consider the cost of those open flame heaters mentioned earlier. As stated, construction sites are usually dotted with several open flame 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 5,000cfm dehumidifier running on propane or natural gas (yes, a dehumidifier can operate on minimal electricity and propane/NG).
Renting a Dehumidifier can almost be a two-for-one Equipment Rental
A rental desiccant dehumidifier will deliver dry air and heat (a by-product of the reactivated wheel on a desiccant DH unit is air heated above the inlet temperature). A desiccant dehumidifier will both control humidity and warm a space. In cool weather this is ideal, controlling moisture and adding warmth is great in fall and winter. The choice of equipment may vary in warmer months. Ultimately, if moisture management is a concern, a dehumidifier is the only type of equipment to consider. If temperature and humidity need to be addressed, incorporating a dehumidifier to your equipment roster is essential. A heater will not solve moisture problems, and as we have discussed, certain heaters will actually add moisture.
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.