R-Value of Drywall: Will Drywall Help Insulate?
All building materials resist the flow of heat and cold to a degree, but some are more effective at it than others. Materials that offer better thermal resistance are naturally better insulators than those with lower thermal resistance. Frankly, while drywall is a wonderful material for many reasons, it isn’t much of an insulator.
What are R-values?
R-value is a shortened term for Resistance value. It measures a material’s capacity to resist the flow of heat and cold, also known as its thermal resistance. R-values are used in the building industry to indicate how well materials insulate. The higher the R-value, the greater the thermal resistance and the better the insulation performance of the material.
R-values increase with the thickness of a specific material. Three inches of blown insulation will have a higher value than two inches of the same material. R-values also are additive for an assembly of materials. In other words if you sandwich a layer of R-value 10 material between two layers of R-value 1 material, the combination has an R-value of 12.
Researchers do not physically measure R-values. Instead, they test for U-values. The U-value, also known as the U-factor, describes how well a building material conducts heat. The R-value is simply the opposite — a description of a material’s resistance to conducting heat. Once testers determine a U value, the R-value is simply the inverse or 1/U-value. If the U-value of a material is .5, the R-value is 2. If the U-value is .25, the R-value is 4.
U-values were actually the industry standard for designating insulation efficiency until 1945 and are still required for some energy modeling programs and code calculations. The lower the U-value, the better the insulation properties of a material. However, since people tend to associate higher numbers with better performance, this proved to be confusing and R-values were created in the 40’s to make it easier to understand which insulating products were more effective.
R-values for Drywall — How Do They Compare?
Drywall has a relatively low R-value — about 0.45 at ½” thickness. This is similar to building materials such as siding, concrete, dirt, face brick, particleboard, wood and single-pane glass. However, it is significantly less than materials that are commonly used for insulation.
|Fiberglass batts||3 ½”||11.00|
|Blown cellulose||3 ½”||12.60|
|Extruded polystyrene (beadboard)||3 ½”||17.5|
Making the Right Choices
Clearly, drywall needs help when it comes to properly insulating a wall. There are many factors that come into play when using R-values to find materials that will meet codes or builder specs. Manufacturer R-values apply only to properly installed insulation. For example, compressing two layers of batting into the space intended for one layer will not double the R-value. Another important factor to consider is that every stud provides an easy route for heat and cold to come and go unimpeded. If the studs in your project are closer together (or you are dealing with large expanses of less energy-efficient glass), you may need to use a more efficient and probably more expensive insulation material to achieve the desired results.
Most drywallers purchase the insulation materials for residential jobs, whether or not they choose to handle the labor themselves. It’s one more aspect of a complicated job. And, in an industry that relies on tight profit margins even at the best of times, it is one more area in which you need an excellent grasp of costs plus clear control over the process. Low bids or time overruns can quickly create financial challenges for your business.
Getting the Right Help
Hyphen Solutions’ SupplyPro GM is cloud-based construction software that helps you effectively manage residential drywall projects from receiving a new work order through approvals and payment. Built for mobility, this effective drywall software gives you real-time information and control in every part of your business. You can:
- Track past costs and create accurate estimates for new jobs.
- Receive new orders and jobs from builders in your "new job inbox."
- Confirm information about a project at a glance, including price, drawings, specs, and supply lists.
- Make accurate decisions about supply orders based on floor plans or site take-offs from field users, captured on custom forms.
- Issue inventory pick lists or PO’s on-demand or at automated points in the process.
- Make and change team assignments based on availability, work type and location.
- Track your teams on-site and real-time job progress.
- Receive change orders quickly.
- Send invoices on approved work automatically.