Insulfoam’s Regional Sales Director, Rick Canaday, joined Home Talk USA with Michael King to discuss insulation in your home, insulation properties, moisture concerns, energy leaks in and out of the home and more.
Originally posted online at Construction Superintendent
Understanding rigid foam insulation for foundation and under-slab applications
Up to one-quarter of a building’s energy loss is due to lack of insulation in below-grade areas, including the foundation and under slabs. Now that high-performance building envelopes are common above ground, the relative amount of total heat lost below grade will grow if these spaces are not addressed.
As a result, superintendents increasingly will encounter below-grade and under-slab insulation on all building types. To help increase understanding of how two common rigid-foam insulations perform in these settings, this article evaluates moisture absorption and thermal performance. It also discusses installation procedures for below-grade and under-slab insulation.
Rigid foam insulation
Two common rigid foam insulations specified for below-grade applications are expanded polystyrene (EPS) and extruded polystyrene (XPS).
An easy way to recognize EPS on the jobsite is that it is commonly white. This insulation is made of expanded polystyrene beads fused into sheet stock and blocks of various densities, compressive strengths and sizes. Historically used as a stable roof insulation, EPS has gained wide acceptance in wall, below-grade and under-slab applications due to its low-moisture absorption, strength and stable, long-term thermal performance. EPS insulation blocks can be custom-cut into a variety of shapes and sizes to meet wide ranging job specifications.
Building professionals have used EPS successfully in below-grade applications for decades. As of 2013, the International Code Council explicitly permits EPS throughout frost protected shallow foundations, under slabs and any other below-grade application.
To make XPS, manufacturers combine and melt polystyrene with blowing agents and additives, then force the liquid mixture through an extrusion die in a continuous feed, where it is shaped, cooled and trimmed to size. The product is most commonly available as boardstock of fixed size and thickness. Manufacturers often tint XPS a primary color for brand recognition.
Moisture absorption and thermal performance
There is much confusion in the marketplace regarding whether EPS or XPS insulation resists moisture better. This is a key point, as wet insulation has lower thermal performance. While manufacturers of both insulation types tout that their products have lower moisture absorption, in-situ tests indicate that EPS performs better in this regard.
For example, in 2008, Stork Twin City Testing – an accredited independent testing laboratory – examined sheets of EPS and XPS removed from a side-by-side installation after 15 years in service on a below-grade foundation in St. Paul, Minnesota. The XPS was significantly wetter on extraction, with 18.9 percent moisture content by volume compared to 4.8 percent for the EPS. After 30 days of drying, the XPS still had elevated moisture of 15.7 percent, while the EPS had dried to 0.7 percent.
The U.S. Department of Energy’s Oak Ridge National Laboratory also reports high moisture absorption levels for XPS. In a 2012 study, the lab reported “all samples of XPS insulation gained much more moisture during the 15 years of contact with soil moisture.” The resulting loss of energy savings performance was 10 percent for a full basement (“deep basement”) and 44 percent for a slab-on-grade installation.
By comparison, the U.S. Army Cold Regions Research and Engineering Laboratory found EPS buried in wetted soil for 1,000 days absorbed only 1.7 percent moisture by volume, which is substantially lower than the XPS rates noted above.
Installing rigid foam insulation below grade
On building foundations, the insulation (whether EPS or XPS) is installed over the damp/waterproofing, after that layer has adequately cured. Crews can use mechanical fasteners or polystyrene-compatible adhesive to attach the insulation. Applying a bead of polystyrene-compatible caulk or mastic to the top of the insulation board minimizes water infiltration behind it.
For under-slab applications, the rigid foam insulation typically should be installed over a gravel base, with a poly vapor diffusion retarder between the gravel and insulation. Additional insulation is applied along the edges of the slab, because that is a primary surface for heat loss. To avoid damage to the insulation, it is necessary to ensure removal of any jagged surfaces or irregularities in the substrate before installing the rigid foam panels.
In either case, it is important to confirm all details with the insulation manufacturer and local building department, and to ensure appropriate construction techniques to drain water away from the building.
In addition to its lower moisture absorption and better long-term thermal performance, EPS has the highest R-value per dollar among rigid insulations. As such, it provides a cost-effective way to insulate building foundations, and under slabs.
Ram Mayilvahanan is the product marketing manager for Insulfoam, which offers below-grade insulation under the Insulfoam and R-Tech brand names. For more information, visit www.insulfoam.com.
Contact Ram Mayilvahanan, Insulfoam’s Product-Marketing Manager
Mercy Hospital | Joplin, MO. | View Project Profile (pdf)
After a force five tornado destroyed St. John’s Regional Medical Center on May 22, 2011, the Joplin, MO. hospital rebuilt with a new stronger facility designed to stand up to devastating wind forces. After the destruction, architects and engineers analyzed how the nine-story structure reacted to the storm. Today, a new facility stands stronger with a big tornado in mind….Mercy Hospital.
One of the largest changes to the hospital was the roof in an effort to harden the hospital’s building envelope. More than any other part of a building, its roof system components must complement each other. Insulation is a crucial component, because it contributes to a roof system’s thermal performance and overall durability while providing a substrate for the roof membrane. Tapered Insulfoam was used to help the new hospital roof combat strength, water absorption, stability, stable R-Value and excellent performance.
By using Insulfoam 15″ InsulRoof Taper EPS as part of the roof system on the new hospital, the resulting structure is 30% STRONGER than the requirements for the old hospital.
In the old facility, the design team learned that the metal with insulation on top was removed by the tornado and exposed the inside of the building. The roof is all concrete decks with a double roof system and a waterproof membrane. The result, if the hospital loses the roof system, there will still be a watertight and concrete-sealed building.
Pre-cut tapered EPS blocks were used to increase roof slope for additional drainage, while offering a long term, stable R-Value, excellent dimensional stability, compressive strength and water resistant properties that meet or exceed the requirements of ASTM C578. The thick blocks can be factory-cut into single-layer tapered pieces that eliminate the labor of stacking multiple insulation panels. Tapered EPS can be adapted to accommodate any roof drainage system and roof configuration.
Labor Savings: There are no complicated filler panel systems. Tapered InsulFoam can be installed in a single layer for thicknesses up to 40″, making it significantly more cost effective than comparable rigid-insulation tapered systems. The ultra lightweight nature of Insulfoam EPS further allowed for fast installation.
Promoted Positive Drainage: Tapered InsulFoam is the ideal insulation for both new construction and re-roofing projects in which positive slope is desired or ponded water is a concern.
Environmentally Friendly: 100% recyclable if ever removed or replaced.
Stable R-Value: EPS’s thermal properties will remain stable over its entire service life. There is no thermal drift, so the product is also eligible for an Insulfoam 20-year thermal performance warranty.
Proven Performance: The same fundamental EPS chemistry has been in use since the mid-1950’s so the actual performance of the product is well known.
Water Resistance: Tapered Insulfoam does not readily absorb moisture from the environment.
Code Approvals: Tapered Insulfoam is recognized by the ICC-ES, and has numerous Underwriters Laboratory and Factory Mutual approvals.
Originally posted online at Buildings.com in Buildings Buzz!
Wet insulation is ineffective insulation – rigid foams that retain high volumes of moisture lose about half of their insulating R-value. Because insulation installed on below-grade building foundations and under concrete slabs is often exposed to moist soil, it is crucial to choose an insulation that has minimal long-term moisture retention and the ability to dry quickly.
For facility professionals that are evaluating insulation for building retrofits or for new construction, paying attention to moisture performance helps ensure effective long-term thermal resistance. Because the insulation will be hidden from view, any problems with degraded materials will not be obvious, although the effect on higher energy bills will be very real.
One challenge in selecting insulation is cutting through the competing claims of insulation manufacturers. Producers of extruded polystyrene (XPS) and expanded polystyrene (EPS) – common below grade insulations – both claim that their products are superior at resisting moisture. In their own ways, each one is right, but it depends on whether one is looking at abstract, standardized tests or performance in actual installed conditions.
Claims that XPS insulation absorbs less moisture than EPS are based on ASTM 272, Standard Test Method for Water Absorption of Core Materials for Sandwich Constructions. This test calls for fully submerging an insulation sample in water for 24 hours, then weighing it for moisture absorption immediately upon removal from the water.
How does this test represent reality? The truth is it doesn’t reflect real-world conditions for two reasons:
1) Unless your building is in a lake or river or subjected to severe flooding, the insulation will not be fully submerged.
2) It doesn’t account for how much an insulation dries out or does not dry out between periods of moisture exposure.
Entire marketing campaigns have been built around this test, but when it comes to what really happens on your building, it’s necessary to look at actual exposure during in-situ tests. Studies of insulation exposure to moisture in actual field conditions show that EPS outperforms XPS by a wide margin, largely because EPS dries much faster than XPS.
For example, the independent lab Stork Twin City Testing evaluated the moisture content of EPS and XPS buried side-by-side for 15 years on a building foundation in St. Paul, MN. At the time the insulations were removed, the EPS was four times drier than the XPS – the EPS had only 4.8% moisture by volume compared to 18.9% moisture content for the XPS. After 30 days of drying time, the EPS had dried to only 0.7% moisture by volume, while the XPS still contained 15.7% moisture.
The high moisture absorption of XPS is further seen in a 2012 report from the U.S. Department of Energy’s Oak Ridge National Laboratory. Researchers found that XPS insulation installed below grade for 15 years had absorbed 67% or more moisture. The resulting loss of energy savings performance for the XPS was 10% for a full basement (“deep basement”) and 44% for a slab-on-grade installation.
Insulation manufacturers are well aware of how their products will perform over the years. Evidence of this is seen in the limitations stated in warranties they offer. This is why XPS manufacturers typically warrant only 90% of the insulating R-value of their products during time in service, whereas most EPS manufacturers warrant 100% of the R-value. Some XPS manufacturers will also void warranties in case of ponding or water immersion, which runs contrary to their highlighting of 24-hour, full-immersion testing.
There are many claims in the market about whether EPS or XPS offers the best moisture resistance. When evaluating such statements, it is important to consider the basis upon which the statements are made. Does the testing involve guys in lab coats dunking insulation into a fish tank for one day, or does it replicate how insulation performs on actual buildings over many years? If facility managers are making the investment in insulation, this is an important distinction to pay attention to, otherwise the product might not perform as desired.
Contact Ram Mayilvahanan, Insulfoam’s Product-Marketing Manager
For years the problem of corrosion has been on the minds of the engineers who manage the Alyeska Pipeline, a pipeline that transports oil from the fields on the North Slope of Alaska. One of the several mountain passes that connects the oil-producing areas of the North Slope with interior Alaska and the south is Atigun Pass…some of the most beautiful country on the planet; however, the harshest as well. Atigun Pass is located at an elevation of 4,739 feet above sea level and is the highest pass in Alaska that is maintained though out the year. The weather is harsh and highly unpredictable providing many challenges such as freeze thaw cycles and high concentration of seasonal moisture.
The problem was in the original design. Rigid flat stock was originally used to insulate below grade transitions of the Trans-Alaska Pipe Line. Over the years the extreme arctic conditions exposed the problem. Freeze thaw cycles and high moisture destroyed the XPS application.
EPS Goefoam was the perfect solution for this problem for both utility protection and utility insulation simultaneously. Custom cut geofoam pipe jackets were the answer with low moisture absorption, light weight for ease of installation, stable thermal protection and locally produced. Geofoam solves a decade long problem for decades to come and extending the life of the Trans-Alaksa Pipe Line one transition point at a time.
New Below Grade Data Released: EPS vs. XPS Insulation: The EPS Industry Alliance (EPS IA) has released NEW moisture absorption data regarding XPS, moisture absorption and the effects on R-Value through the latest Technical Bulletin, EPS Below Grade Series 105: XPS Insulation Extracted After Field Exposure Confirms High Water Absorption & Diminished R-Value, March 2014 (pdf)
A Truly Green, High-Performance & Economical Wall Insulation.
R-Tech for Insulated Tilt-up (IT) applications is a high-performance, rigid insulation consisting of a superior closed-cell, lightweight and resilient expanded polystyrene (EPS) with advanced polymeric laminate facers. R-Tech IT is available with factory laminated MR (metallic-reflective) facer on one exterior side, and a white protective facer on the other exterior side.
The R-Tech facers act as the slip sheet to minimize bonding between the foam, Facia Wythe and Structural Wythe wall. The core of R-Tech is the same high-quality as our InsulFoam brand insulations and meets or exceeds the requirements of ASTM C578, Standard Specification for Rigid, Cellular Polystyrene Thermal Insulation. R-Tech has excellent dimensional stability, compressive strength and water-resistant properties.
R-Tech insulated Tilt-up (IT) is designed for both commercial and residential tilt-up wall applications.
R-Tech IT is available in 4′ x 8′ sheets with thicknesses ranging from 0.5″ to 4.5″. R-Tech IT can also incorporate the InsulSnap feature which allows the end user to cleanly break the 4′ x 8′ sheets into a desired width. Custom sizes are available upon request (lengths up to 16′).
- User Friendly. R-Tech IT can be ordered with the InsulSnap feature which scores the product longitudinally at any pre-ordered interval (commonly 16″ or 24″ o.c.) to accommodate different locations for the tiles. The InsulSnap feature minimizes labor by enabling the installer to cleanly break the product at the desired width while also minimizing product breakage and waste.
- Jobsite Durability. With a polymeric facer on either side of the R-Tech IT, it is an extremely flexible and durable insulation.
- Water-Resistant. R-Tech IT facers provide a surface that is virtually impervious to moisture.
- Stable R-Value. R-Tech has no thermal drift. Designers are well served knowing the R-Tech IT thermal properties will remain stable over its entire service life. R-Tech is eligible for an Insulfoam 20-Year Thermal Performance Warranty – a warranty that’s not prorated or limited to a percentage of the published R-Value.
- Cost-Effective. R-Tech is typically less expensive than other cavity wall insulations.
- Environmentally Friendly. R-Tech may contain up to 15% recycled material and the foam core is 100% recyclable.
- More R-Value per dollar than any other rigid insulation product
- R-Value doesn’t degrade over time
- Most cost-effective insulation – typically 25-40% less than other rigid insulations
- Easy to install – reduces install labor costs by more than 50%
- Code recognized insulation (ICC-ES, UL) at an economical price
- Complimentary 20-year thermal performance warranty available
Engineered for Versatility
- Available in 0.5″ – 4.5″ product thicknesses
- The right product for any job. Available in multiple densities, compressive strengths and panels sizes
- Meet or exceed ASTM C578 requirements.
- Lightweight panels -easy to install
- Highly durable, yet resilient
- Simple to cut in the field with a saw or hot wire kit
- Custom, job-specific sizes with no additional lead time
- 100% recyclable, may contain up to 20% recycled content
- High long-term thermal performance (stable R-Value) conserves energy and operational costs
- Contributes toward LEED energy efficiency points
- Does not support old or mildew growth for improved indoor air quality (IAQ)
- Naturally water resistant – does not readily absorb moisture from the environment
- Regional manufacturing throughout North America reduces transportation costs to job sites, and environmental impact.
Problem: Deep water and winter freeze cause manhole jacking and separation.
A manhole located in Class ‘A’ wetlands in the city of Anchorage AK., experiences severe frost damage. Adjacent to a creek and subject to high water table and deep winter freezing, over the years frost pulled the manhole apart causing the lid and grade rings to fall off, the cone section to tilt 35° from vertical, and the 4” thick reinforced concrete barrel section broke away from the base, allowing ground and surface water to flow freely into the manhole. End result, soil erosion around the manhole and in the winter months, jacking of the manhole sections and displacement.
Solution: To stop the jacking and the movement EPS Geofoam acts as an insulated concrete form and later as a compressible inclusion virtually eliminating the jacking around, separation and erosion. EPS Geofoam in earthworks applications provides the benefit of reducing both vertical and lateral pressures on below ground structures.
- Reduces associated structural costs
- Does not require surcharging, preloading or staged construction
- No secondary compaction required
- Not weather-dependent- can be installed during rain or snow
- Does not require heavy equipment to move
- Ease of installation, ease of cutting
- Available in job-specific block sizes
- Engineered per project specifications – can match compressive resistance with job requirements
Save Energy and Reduce Interior Noise with Insulfoam’s Garage Door Insulation Kit…
The largest uninsulated space in most homes is the garage door. Insulfoam’s Garage Door Insulation Kit provides one of the easiest and most cost effective ways to increase the energy-efficiency of your home. Watch our installation video to see how simple it is to install insulation to the inside of your garage door in less than an hour. These rigid high-impact panels tightly fit standard garage sizes (8′ and 9′ garage doors); however, can be cut to fit non-standard garage doors. Pick up an Insulfoam Garage Door Insulation Kit at your local Lowe’s or Home Depot home improvement store.
Originally posted online at Constructor Magazine, Web Exclusive
USING GEOFOAM TO SIMPLIFY COMMON SITE PREP CHALLENGES
Contractors have successfully used expanded polystyrene (EPS) geofoam to simplify site preparation since the 1960s. Projects built with the material include road beds, bridge approaches, levees and other civil jobs. Now, geofoam is increasingly solving a host of construction challenges in commercial buildings and large residential applications.
Geofoam is an ultra-lightweight, engineered, closed-cell rigid foam. The material is about 100 times lighter than soil and weighs substantially less than other lightweight fills.
Even though it is very light, geofoam is high strength, with compressive resistance values of 317 to 2,678 lbs/ft2 at a 1 percent strain. Geofoam is suitable for a range of heavy loading conditions, including sub-base for pavements and railroads bearing jet aircraft and locomotives.
EPS geofoam changes the traditional soil compaction phasing method in which contractors mechanically compact soil to a percentage of dry density and pay for multiple samples and laboratory tests. Unlike other lightweight fills such as shredded tires or wood chips, EPS geofoam is homogenous, which provides uniform load transfer and eliminates differential settlement.
GEOFOAM APPLICATIONS AND BENEFITS
The combination of lightweight and high strength makes geofoam the ideal material for many building applications, including:
• Creating level building pads on steep-sloped lots
• Stabilizing steep slopes
• Remediating soft soils
• Forming swimming pools and pool decks
• Creating theater/stadium seating
Creating level building pads on steep-sloped lots
Given its lightweight, contractors can use geofoam to simplify construction of retaining walls needed to level steep-sloped lots. Geofoam drastically reduces or can eliminate the lateral load on retaining walls, so walls do not need to be as robust. Material and labor costs are much lower due to reducing forming, structural steel and concrete volume, and lessening or eliminating the need for geogrids or mechanical tiebacks.
Eckhart Construction Services, a Carolinas AGC member, used geofoam to create a level building site for a McDonald’s restaurant. There, a retaining wall was needed that could accommodate the change in grade, as well as reduce the load over extremely soft soils. Typical soil fill would have caused unacceptable settlement of the retaining wall. The use of EPS geofoam allowed for incorporation of a traditional keystone retaining wall while eliminating the need to use the typical geogrid material to reinforce the retaining wall.
Stabilizing steep slopes
Geofoam’s lightweight makes it an excellent option for stabilizing steep slopes, without the need to change the final slope geometry. Since the material is much lighter than other fills, it greatly reduces the weight of a slope’s driving block and lowers the risk of costly and dangerous landslides. An additional advantage of using lightweight geofoam blocks on slopes is that crews can move and place them by hand. This eliminates the need for heavy earth moving and compaction equipment on steep and uneven terrain.
Remediating soft soils
Ground with soft soils or soft clay makes building construction notoriously difficult. To eliminate or greatly reduce the need for time-consuming and costly surcharging of soft soils, EPS geofoam provides high load support at a low weight for projects of all sizes.
An example is the renovation of an existing office building into a city hall in the Pacific Northwest. Building codes required installation of new handicap ramps as part of the upgrade. The challenge was the project site is situated on extremely soft glacial till at the south end of a lake. As such, the ramps needed a very lightweight void fill to avoid post-construction settlement. After evaluating various lightweight fill options, the project team chose EPS geofoam. Crews installed 5,000 cubic yards of geofoam, which played a role in helping the project be completed two months ahead of schedule and nearly $600,000 under budget.
Forming swimming pools and pool decks
Contractors use geofoam to simplify construction of swimming pools in residential, commercial and institutional uses, including hotels, schools and community centers. Project teams can order the blocks pre-cut to precise dimensions or can easily cut them to size and shape on site. This simplifies the concrete forming process, and greatly reduces weight for construction of rooftop pools or on sites with poor load-bearing soils. Once crews form the pool basin and decks with geofoam, they can apply shotcrete directly to the foam.
Because crews can readily form geofoam into a host of shapes, the material provides a simple way to create landscape topography and berms. This is particularly beneficial when loads must be minimized on underlying structures and utilities. Examples include rooftop gardens and landscaped spaces with shallow buried utilities that cannot bear the weight of soil fills.
Creating theater/stadium seating
Geofoam provides contractors a fast and simple way to change slopes within buildings – either creating tiered seating as in auditoriums, movie theaters, churches or gymnasiums, or leveling out such a sloped space for other uses.
For stadium style seating, crews hand place row upon row of geofoam blocks to achieve the necessary profile. They can then either place concrete over the geofoam as shotcrete or as pre-cast panels. Using geofoam greatly simplifies the forming process and eliminates the need for complex tiered compacting of soil to form the stepped profile of stadium seating.
Crews can also use geofoam to quickly level an existing sloped elevation in a building. For example, a university wanted to convert a sloped floor lecture auditorium into a surgical suite at a hospital. The project engineers specified EPS geofoam as a structural void fill to reverse the slope. The EPS supplier cut the blocks to minimize field fabrication on the job site. Because the enclosed auditorium did not have space to accommodate heavy equipment, and as noise from mechanical compaction of soil would have disrupted hospital patients and staff, geofoam was an ideal alternative. The lightweight structural fill provides a strong, stable sub-base for the new, level concrete floor slab.
WORKING WITH GEOFOAM
Although geofoam can be manufactured in many sizes and shapes, standard blocks are typically 4 feet wide by 8 feet long, and of varying thickness. If contractors do not order geofoam precut to specified dimensions, they can easily trim geofoam to size using a hot wire cutter (which some manufacturers will supply) or with a handsaw or a chainsaw onsite.
When placing geofoam, the blocks are staggered so their joints are not located in the same vertical plane. At times, the blocks are interconnected with either barbed plates or polyurethane adhesive, in accordance with engineering specifications.
Due to geofoam’s lightweight, crews can maneuver and place the blocks by hand or with small mechanical equipment. A typical installation is to place geofoam blocks on a level course over sand, pea gravel or any locally available permeable leveling course material.
Following are points to keep in mind when working with geofoam:
• Geofoam is subject to damage when exposed to certain hydrocarbon chemicals or solvents. If needed, crews can protect the material with hydrocarbon-resistant geo-membranes or concrete slabs.
• Manufacturers treat geofoam with a fire retardant to avoid the rapid spread of fire. However, the material is combustible at high temperatures, so it is important to be cautious when conducting hot work, such as welding, around geofoam.
• Exposing geofoam to sunlight for extended periods can cause superficial discoloration, which does not impact the product’s integrity and can be removed with a broom or very light pressure-washing, if desired.
• Because geofoam is lightweight, it is important to take care when stockpiling the material on job sites where windy conditions exist. Contractors should weigh or tie-down stockpiles, as necessary.
Soil fills will continue to factor prominently in construction given their ubiquity and familiarity, but for challenging projects, geosynthetics like geofoam are increasingly popular. Geofoam offers contractors a simple-to-use, engineered alternative to traditional earthen fills. The material solves a host of site preparation challenges in commercial and large residential building projects.
INSULFOAM GEOFOAM QUESTIONS:
Contact Nico Sutmoller, Below-Grade & Geofoam Specialist
Originally posted in Modern Contractor Solutions Magazine, June 2014 issue
Three tips for choosing the right material for your project
Which insulation is best for use on buried building foundations and under concrete slabs? Sales reps, naturally, will tell you that their company’s product is best. But, what does independent testing and research say?
These three tips will help your firm select a cost-effective and high-performance rigid foam insulation type for your next below-grade insulation job.
1. CONFIRM LONG-TERM THERMAL PERFORMANCE
Two of the rigid foam insulations most commonly used below grade and under slabs are expanded polystyrene (EPS) and extruded polystyrene (XPS). Although both are closed cell insulations, they perform very differently over the long term.
XPS has a higher initial insulating R-value than does a similar thickness and density of EPS, but the R-value of XPS degrades over time. EPS does not experience such “thermal drift,” and the reported R-value remains the same throughout years of installed service.
This is a crucial point when selecting insulation, as a decreasing R-value means lower thermal performance over time, and thus increased heating and cooling energy and costs for the building owner.
A simple way to confirm an insulation’s long-term thermal performance is to review the warranty. Established EPS manufacturers typically warrant 100 percent of the published R-value for 20 years. By comparison, most XPS warranties typically cover only up to 90 percent of the published R-value, to account for the R-value degradation that occurs in the field.
2. ENSURE MINIMAL LONG-TERM MOISTURE ABSORPTION
In addition to R-value stability, rigid foam insulations differ in their rates of moisture absorption and their ability to dry. Wetted insulation provides lower thermal resistance and can degrade over time. Since insulation installed below grade frequently contacts wetted soil, rates of moisture absorption and the ability to dry is key in these applications.
Independent laboratories have conducted extensive tests of moisture absorption rates for both EPS and XPS. Although XPS often rates better in laboratory short term, fully submerged tests, real-world long term tests show that EPS performs much better. The reason is that EPS has the ability to dry much faster than XPS. This ability to dry at a fast rate helps EPS remain drier during conditions of repeated exposure to moisture.
A 15-year in-situ test of EPS and XPS dramatically demonstrated this point. Stork Twin City Testing evaluated the moisture content of EPS and XPS buried side-by-side for 15 years on a building foundation in St. Paul, Minnesota. At the time the insulations were removed, the EPS was much drier than the XPS—the EPS had only 4.8 percent moisture by volume, compared to 18.9 percent moisture content for the XPS. After 30 days of drying time, the EPS had only 0.7 percent moisture by volume, while the XPS still contained 15.7 percent moisture.
The high moisture absorption rate of XPS in real-world settings is further seen in a 2012 report from the U.S. Dept. of Energy’s Oak Ridge National Laboratory (ORNL). Their researchers found that XPS insulation installed below grade for 15 years had absorbed 67 percent or more moisture.
3. TARGET AN APPROPRIATE COMPRESSIVE STRENGTH
One of the best ways to save money on rigid foam insulation installed under concrete slabs is to ensure the material is not over-engineered. A common design assumption leads to specification of rigid foam strengths that are many orders of magnitude higher than necessary, which can double the insulation material cost.
Without getting into extensive technical details and mathematical formulas, the problem is engineers often use an overly conservative approach for insulation under concrete slabs. Many designers assume that point loads applied to a slab, such as those from the wheels of a forklift, transfer to the insulation in a triangular load path. Yet, concrete slabs distribute loads more uniformly than this, which means the insulation does not need as high of a compressive resistance as when one assumes a concentrated triangular load path.
An overly conservative design approach often results in specification of a high compressive resistance XPS product, when a more cost-effective EPS would offer sufficient strength. Since XPS typically costs more per inch than EPS, this is wasted money that comes off the contractor’s bottom line.
A simple solution for contractors is to ask the designers if they are using a formula from the Theory of Plates on Elastic Foundations, which take into account how slabs and insulation behave together. A resource to point them to for example calculations is the article “Right-sizing Under-slab Insulation,” in the April 2014 issue of Structure magazine.
With building owners’ growing desire to save money on heating and cooling costs, and increasingly stringent energy codes, contractors will be installing below-grade and under-slab insulation on more of their projects. EPS insulation out-performs XPS for both long-term thermal resistance and long-term moisture absorption, and EPS comes in a variety of compressive strengths suitable for nearly all building projects. With the highest R-value per dollar, EPS is the cost effective insulation choice.
Contact Ram Mayilvahanan, Insulfoam’s Product-Marketing Manager
More news coverage on the use of InsulFoam Geofoam in Chicago’s newest and biggest downtown attractions, Maggie Daley Park. When complete, the new park will have a distinctive presence with signature elements like rock-climbing sculptures, an ice-skating ribbon, and play garden. Read more in the latest and on-going news coverage on details and view the project’s job site camera:
Originally aired and published on ABC 7 Chicago News, by Paul Meincke
In the shadow of towers made of concrete and steel, there are building blocks of a different sort. Thousands of them are being layered together to give shape to what will be Maggie Daley Park.
“We’re going to transform what was a flat, sort of uninviting area into a gem for Chicago that compliments Millenium Park,” said Chicago Park District CEO Michael Kelly.
That transformation has a lot to do with topography. When this 20-acre park is done, its northeast corner will sit 30 feet higher than the southwest. That’s a lot of dirt. And dirt weighs a lot. And a lot of weight would not be welcome atop the two story parking garage that sits directly underneath. So, what do you use? Geofoam.
“Geofoam is essentially Styrofoam. It’s lightweight fill,” Kelly said
It’s 100 times lighter than soil. Geofoam isn’t a new concept. It was used here before, but there’s a lot more of it now, 75,000 cubic yards of it will be sculpted and tacked down to create a rolling terrain.
On top of the geofoam goes the dirt which will be deep enough in spots to accommodate the roots of one-thousand new trees. If you’d never seen the geofoam going in, you’d never know it was there.
“That’s essentially the best compliment we could get once this park is open and that is that people don’t realize that it’s a park constructed on top of a garage,” said project engineer Nichole Sheehan. “It’s a park that people are going to love and hopefully come to all the time.”
The park district has been recording its birth with time lapse camera, from barren garage roof to the building of baby hills, and when the park’s soft opening comes next fall, this is the vision. Three of the 20 acres devoted to a children’s playground. Just up the path, a 25 foot climbing wall, and when the cold months come, a feed of built in refrigerant will convert that path into a 400 meter ice skating ribbon – attracting old Hans Brinkers or perhaps young Blackhawks.
From debris dating back to the great Chicago fire to geofoam, this piece of Chicago has undergone remarkable change over the years.
In the late 40’s and early 50’s, there were lots of railroad, lots of parking that over the years goes went away or went underground.
“Somewhere way down there, there’s fill,” Kelly said. “There’s probably some old railroad scrap. Now we’re standing on geofoam and we’re building a green park. We’re building a 20 acre green roof is essentially what we’re doing with a thousand trees.”
The first of the trees come soon. The grand opening of Maggie Daley Park comes next Spring. Its birthing thus far carries four words welcomed in urban re-design.
Maggie Daley Park carries a roughly $55 million price tag. Most of that comes from parking garage lease money and private contributions along with five million in park district capital funds.
INSULFOAM GEOFOAM QUESTIONS:
Contact Nico Sutmoller, Below-Grade & Geofoam Specialist
Target | King of Prussia, PA | View Project Profile (Pdf)
R-Tech Below Grade provided 25% cost savings in insulation on the project without sacrificing performance.
The Target store located in King of Prussia, PA was constructed different than most and was not built as a slab on grade. The bottom level of the building is a parking garage while the retail space is located on the second level. Target used InsulGrade R-Tech as a between slab insulation as a way of insulating the floor of the retail space and providing a thermal barrier between the concrete planks and the floor slab.
DOW XPS was initially specified on the Target project, however; R-Tech was substituted and provided a substantial cost savings while providing both long-term stable and non-degrading R-Value.
PROBLEM & SOLUTION
Space was a challenge for this Target project as the parking garage is on the ground level and the actual retail floor is on the second level. Concrete planks were installed as the base substrate. R-Tech was then installed over the plank to insulate the interior of the retail space from the open parking garage underneath. A topping slab was then poured over the R-Tech to create the retail floor. The R-Tech insulation has a long-term stable R-Value and is eligible for an Insulfoam 20-Year Thermal Performance Warranty … a warranty that’s not prorated or limited to a percentage of the published R-Value.
InsulGrade R-Tech features a premium factory-applied laminate polymeric facer that is virtually impervious to moisture, keeps water from entering the insulation, and away from concrete foundations and slabs. Available in 4′ x 8′ panels and thicknesses starting at 3/8″, with compressive strengths from 10-50 psi.
- Architect: Mulvanny G2 Architects
- General Contractor: Whiting-Turner Construction
- Contractor: Madison Concrete
- Supplier/Distributor: Gatti Morrison
- Insulfoam Product: Approximately 150,000 sq. ft. of R-Tech IV (25 psi), 4″ x 4′ x 8′ and 6″ x 4′ x 8′ sheets
EPS vs. XPS
- Both EPS and XPS are closed-cell insulations
- EPS and XPS below grade insulations are covered under the same standard- ASTM C578
- EPS has a more stable R-value and less long-term moisture retention than XPS
- XPS is 20-40% more expensive for the same compressive strength
- Highest R-value per dollar
- 100%, 20 year R-value warranty
- 10-30% less than XPS insulations
Green From the Start
- Up to 20 LEED points possible
- 100% recyclable
- contains up to 15% recycled content
- Minimal job site waste
- No thermal drift
- Helps preserve energy and fossil fuels
R-Tech has been used successfully for numerous commercial, industrial and residential applications:
- Below grade insulation
- Waterproofing protection board
- Cavity walls
- Interior walls
- Cold storage & freezers
- Concrete panel insulation
- Concrete slabs
- Radiant heated floors
PROJECT OR EPS QUESTIONS
Contact Jason Myers, Insulfoam Territory Sales Manager
Expanded polystyrene (EPS) Geofoam has been used as a geotechnical material since the 1960s. EPS Geofoam is approximately 1% the weight of soil and less than 10% the weight of other lightweight fill alternatives. As a lightweight fill, EPS Geofoam reduces the loads imposed on adjacent and underlying soils and structures.
Sitka Alaska has found a solution to an ever present engineering challenge. It’s not just another tool in the tool box, it is the tool… EPS Geofoam. The Geofoam solution has made the reconstruction of Sitka’s Moller Field, the “Field of Dreams”. Dating back to the 50’s, it was considered the premier baseball field of Southeast Alaska. Over its history it became a horrible marsh due to the deep poor soils it was built on. Today it is the only all-turf field in Alaska.
The field’s reconstructionsuccess was due in large part to Geofoam. Geofoams’ use reduced the overall weight of the field and gave rigidity to the otherwise waterbed like third class field that it was. Today it is the field the rest of the state wished it had.
More Geofoam articles and profiles:
- Foam Blocks Form Hilly Lanscape at Maggie Daley Park Site
- Applications, Design & Construction Considerations for EPS Geofoam
- Utilizing Geofoam in Foundation Design for Steep Sloped Lots
- Project Profile: Idaho Bridge Expansion & Replacement
Lightweight Architectural Shapes
Building Components – EIFS & Stucco Products – Packaging – OEM Parts
When it comes to architectural shapes, if you can design it we can bring it to life. No matter how big, small, detailed or complex, creating dramatic interiors and exterior details, intricate packaging, EIFS and stucco products, or original equipment manufacturing (OEM) components, Insulfoam’s custom shapes machine can create a lightweight yet strong foundation to match anything you can dream up.
Shapes can be produced exactly to your specifications or chosen directly from our Architectural Elements Collection catalog.
EPS Is Field Tested & Proven for 50+ Years
- Highest quality closed-cell foam
- Less expensive than PVC and other foam shape/packaging options
- Custom cuts are no additional charge
- Economical for shipping
- Guaranteed to hold its shape
- Less than 3% shrinkage compared to 8% with EVA
- Will not collapse or breakdown
- Holds no moisture, stays dry in exterior and marine applications
Ideals for resorts, retail chains, store fixtures, commercial and residential applications Insulfoam can help create:
- Columns & Bases
- Pediments & Arches
- Wall Caps
- Ceiling Tiles & Panels
- Reveals & Bands
- Intricate Mouldings
- Custom Medallions, Quatrefoils, Quoins
- Wood Beams & Cast Stone
- Theatrical Sets & Props
- Fireplace Surrounds
- Exterior Signage
- Shutters… and MORE!
EIFS & Stucco Products
A natural insulation product for IEFS and Stucco wall systems. Insulfoam can manufacture EPS in a large range of block and panel sizes, and in a wide assortment of shapes and densities. In addition, Insulfoam offers a long-term, stable R-Value and has excellent dimensional stability, compressive strength and water resistant properties.
Packaging & OEM Parts
Insulfoam helps create super strong, yet light weight packaging components, large crates, internal product components such as cushions and seating, floatation and marine foam, refrigeration and more!
CAD Shapes Machine Capabilities
- Shapes sizes up to 16 feet long
- Extreme cutting dimensions: X: 192″ – Y: 48″ – Z: 144″
- Accuracy ± .002″/foot (0.0167 mm/m)
A Truly Green, High-Performance, & Economical Design Option
Engineered for Versatility
- Available in 0.5″ – 40″ product thicknesses
- The right product for any job. Available in multiple densities, compressive strengths and panel sizes
- 30-40% less than other architectural shape options
- Light weight foam less expensive to ship and easier to install
- Using EPS for simulated concrete, stone and wood components is much more economical and responsible than heavy wood & stone building materials.
- 100% recyclable, may contain up to 20% recycled
- Does not support mold or mildew growth for improved indoor air quality (IAQ)
- Naturally water resistant- does not readily absorb moisture from the environment
- Regional manufacturing throughout North America
Topaz Bridge Expansion & Replacement | McCammon, Idaho | View Project Profile (pdf)
Idaho’s heavily used trucking route and bridge (circa 1940) expands from 2 to 4 lanes to increase safety and capacity using InsulFoam Geofoam.
Idaho Transportation Department’s first EPS Geofoam project was designed by Terracon Engineers and JUB Engineers of Boise. EPS was specified as a soil replacing embankment fill material due to poor foundation soils and 2 steel fish culverts that could not bear the weight of traditional soil fill. A new three-span, bridge replaced the existing bridge (from the 1940’s) crossing rail road tracks and expanding the highway to 4 instead of 2 lanes. 23,000 cubic yards of large block EPS was installed by Scarsella Brother Inc. and supplied by Insulfoam.
The expansion of the US-30 and bridge replacement required a new fill embankment to support the new roadway and bridge approach on a very steep side slope.
The new (600 ft long) expanded bridge clears The Pontneuf River as well as the Union Pacific Railroad tracks, and required a new higher grade of both the bridge structure and the existing roadway to support the new wide and long center spans.
As a result the new bridge approach embankment would be 45-50 feet high, too costly to be retained by conventional concrete cantilever or MSE wall, and raised concerns about global stability.
Further challenges to the project design were the site conditions. Located adjacent to the Portneuf River, shallow bedrock and loose or soft sediments underlie the new approach embankment. This both challenged the new roadway embankment’s strength and stability, and limited deep foundation designs required with concrete walls.
THE EPS GEOFOAM FILL SOLUTION
To reach the new bridge’s approach embankment height of 45 feet, engineers chose a combined fill solution. The lowest 15 feet was a small earthen embankment, while InsulFoam GF constituted the upper 30 feet. 4 1/2 feet of granular fill retained in wire gab ions and an asphalt pavement section were installed directly on top of the EPS blocks to complete the full height of the new embankment.
The soft sediments underlying the site required the lower earthen embankment to settle (80 days), but the InsulFoam GF block fill required no additional surcharge time or secondary compaction by the contractor. Traffic moved on the existing roadway throughout the installation of the upper embankment, which was a key factor for the expansion to finish when weather conditions permitted.
The ultra lightweight nature of EPS allowed the total design weight of the tall embankment to be week under the bearing capacity of the poor foundation soils which aided ITD in successfully completing their first EPS Geofoam project.
Geofoam Lightweight Geo-synthetic Fill:
- Soft Soil Remediation
- Lateral Load Reduction
- Slope Stabilization
- Buried Utility Protection
- Structural Void Fill
- Predictable Elastic Modulus
- Exceptional Strength & Stability
- Exceeds 75 year Design Life
- Weather, Insect & Mold Resistant
- 100% Recyclable
MORE GEOFOAM SOLUTIONS IN HIGHWAY CONSTRUCTION
- Lightweight Geofoam Fill Supports Highway Construction, Siteprep Online
- Geofoam Saves Time, Money During Three Projects, Better Roads Magazine
- Geofoam Offers Performance and Efficiency for Bridge Reconstruction, Modern Contractor Magazine
INSULFOAM GEOFOAM QUESTIONS:
Contact Nico Sutmoller, Below-Grade & Geofoam Specialist