We have been observing the approach of designers using the point load bearing calculation method and specifying insulation strong enough to carry that presumed load. Most of them used the triangular load path calculation. The thought process of the designers, were a conservative approach, the more PSI insulation strength the better - a type of “over engineering.”
Is this over engineering approach good? Does it have a detrimental effect on a structure? The Geofoam Industry (foam insulation beneath highways) learned the hard way and have adjusted their approach. They concluded that loads on slabs should not be look at as “Concentrated Triangular Point Load” but more in line with a slab that works more uniformly as a system as concrete slab distribute loads are more in an even fashion. The DOT and Geofoam Industry took a new approach to load issues. Use the least Compressive Resistant Geofoam Insulation that can handle the load.
How does this information translate to below grade insulation in residential or commercial construction? This is where it gets interesting. Everything we learned and accepted, in regard to, below grade insulation, by the XPS Industry, has been misguided. We have really only looked at half of the equation and most of the time, we have only considered point loads instead of slab distribution loads. We have been concentrating on loads from the top down only. In most ways, we have been ignoring what the soil is really doing below - not just what the soil can bear. Why you ask? Maybe because it gets too complicated. Not making this a forum on soil engineering, let’s just simply say soils are not always consistent and are constantly moving.
So this brings up many questions including - how does soil engineering effect below slab insulation? What are the effects of expansive soils on insulation? Is over engineering insulation compressive strength on slabs bad or harmful?
When we intersect structural engineering and geotechnical engineering, we find that in most cases - “Less is Best.” The lower the compressive strength, that still meet load requirements, is best. The insulation should act more as a stress cushion. Once the insulation has been in place for sometime, it should continue to act as a stress cushion.
The Theory of Plates on Elastic Foundations is a great way to calculate slab deflection and the resulting stress. The formula is (P/8)√(K/D). (Paper written by Timoshenko and Woinowsky-Krieger) We have been following these calculation in Geofoam for sometime now and have had less structural issues and have reduced Geofoam costs dramatically.
In regard to below grade insulation in residential construction, using products like XPS 250 with a 25 psi compressive resistance, as a standard, is not taking into account all of the factors in construction. This standard can be doing more harm than good. Because of the marriage of geotechnical and structural engineering, the industry has now began to understand this and revised its position on below grade insulation. It is time to move to these new standards.
Plymouth Foam is viewing this “Less is Best” change to run parallel with their research. We believe that this concept can reduce construction issues. Using products that are 10, 12 or 15 psi will have more advantages to the structure and in the end reduce cost. We call this the true definition of Value Engineering.
By John Calkins
Green Roofs continue to grow in popularity, especially in large urban areas. These areas can suffer from the “Heat Island Effect” which is caused by black roofs, black asphalt parking lots, concrete and lack of green space. Green roofs, also known as “living roofs” or “vegetated roofs” use plants to lower roof temperatures and create a biodiversity ecosystem encouraging additional habitats of plants and animals.
Plymouth Foam has been involved in numerous green roof projects and have noticed that Engineered DuraFill EPS (GeoFoam) has turned out to be the best solution. Here are the reasons we discovered:
- DuraFill EPS is a closed cell, yet breathable to expel moisture
- DuraFill EPS holds its R-value and does not leach chemicals
- DuraFill EPS can be manufactured formed to accommodate water flow
- DuraFill EPS has high compression resistance for loading
- DuraFill EPS has larger payback and lower costs
Plymouth Foam’s DuraFill Green Roof Products can help reduce cost by combining several products into one combination product reducing labor installation costs. Where most systems have insulation above the waterproofing membrane exposed to moisture, DuraFill can be engineered to move water more efficiently to the drains. DuraFill EPS can be designed to have predictable compression for walkways, loads and foot traffic.
Using your roof to create garden or outdoor living space can greatly reduce your heating and cooling costs. It can also help to reduce the Heat Island Effect.
A properly designed Geofoam Green Roof can increase the life span of the roofing system by improving water flow, reducing ultraviolet exposure to the roof membrane and reducing insulation below the waterproofing membrane which lowers thermal roof stress.
Before we delve into the “whys” we really should look at the effects of ponding water on the roofing system. Ponding water can have the following effects:
- additional loading to the structure
- additional time for moisture pathway to open and allow intrusion
- accelerated material degradation including reflectivity and sunlight magnification
- freeze/thaw pressure from moisture seeping into cracks
- insulation compression
- dirt and debris build up that can cause mold or plant growth
- safety issues - electrical or slipping and falling
- voids warranties
The effects of ponding roof can be a safety issue as well as a serious financial issue. If most roofers are aware of the hazards of ponding water then why are there so many roofs that do not drain well? What are the common causes for poor drainage?
- structural deck deflection
- weep hole’s on connected building sections too low
- no or poor structural slope
- poorly designed tapered insulation system
- cost cutting
- poor detailing
- drains/scuppers/gutters plugged
After walking and inspecting millions of square feet of roofing, I have come to the conclusion cost plays a sad, but significant role. I believe roofers feel cost pressure from owners that do not fully understand the ramifications. I will share some examples.
- A roof that has deck deflection issues, retrofitted for cost savings instead of torn off and the deflection was not addressed properly.
- I referred “poor detailing” but what I really meant was that the good detailing was too expensive and the standard detailing was used as it was ok in the book. (example of this, HVAC units that stop the flow of water drainage and needed to be raised and saddles installed to divert water around the unit - not done… not in bid or too expensive or a pain/time to disconnect.)
- Another one I hear is that Polyiso tapered insulation is to expensive and I can go with a 1/8” pitch, that should work.
- Weep holes, I can’t go above the weep holes, its too expensive to modify or change.
I understand the competitive world of bidding but I have some recommendations that can Keep Your Standards Up and Your Cost Down. I hear building owners constantly saying, “ I want things done right.”
RECOMMENDATIONS: Keep Your Standards Up and Your Cost Down
- Instead of using overpriced Polyiso, value engineer and use EPS for the tapered. - save money. Learn about cost saving in EPS
- Use 3/8” tapered as a minimum instead of standard 1/4” as it moves the water better and can overcome many of the detail or structural slope issues. Learn More
- Disconnect units and other projections for proper height requirements and proper water flow.
- Learn how to move weep holes which can offer the ability to increase insulation heights and have better drainage.
- Use EPS saddle and crickets to make sure water moves around units, projects and even between drains. Saddles can be a roofers best friend.
Many myths about rigid insulation have been spread over the years, especially concerning EPS. Some of these EPS myths refer back to an extinct product called bead board. Modern day Engineered EPS is so different and technologically advanced, it’s amazing some still get confused. EPS have made major advancements in chemistry, fusion, expansion, steam quality and TQM. Plymouth Foam, the leader in foam, has state-of-the-art proprietary manufacturing technology to make the product even better.
Lab and field research have lead to new conclusions about the two rigid insulations especially in below grade applications. EPS rigid insulation is certainly been found to be superior to XPS in so many ways. The following is just 12 reasons why.
1) Higher R-Value Retention:
EPS does not suffer from the same plight as XPS in regards to “Off Gassing.” XPS has blowing agents that initially give it a higher R-value, but these gasses escape over time, lowering the R-value.
Engineered EPS can be made in various densities and can achieve compressive strength up to 8,640 lbs/ft and flexural strength up to 10,800 lbs/ft. It is amazing that such a light product, that is 98% air, is so strong.
3) Moisture Management
EPS insulation is non-hygroscopic and does not readily absorb moisture from the atmosphere. Its closed-cell structure reduces the absorption of moisture into the insulation material yet it can readily expel any absorbed moisture.
4) 100% R-Value Warranty
Due to the R-value stability of EPS, Plymouth Foam offers a lifetime limited 100% R-Value Warranty. XPS offers a 90% R-value warranty.
5) No Harmful Chemicals
EPS does not have VOCs or other harmful chemicals in its product. XPS use of chemical HFCs has been deemed to have a high GWP.
6) Cost Advantage
R-value cost per inch is far less in EPS insulation vs XPS Insulation. Value engineering can be used to save $1,000s on projects.
7) Superior Bonding
Due to the manufacturing process, EPS and XPS provide a far different exterior surface. EPS cell structure provides superior bonding.
8) Made in USA - Made in Wisconsin
Plymouth Foam’s EPS is made in Wisconsin and brings jobs, reduces taxes and helps create a better economy for our state. Made in USA.
Engineered EPS is superior in customizing thickness, lengths, shapes, tapers, chases and can even have reflective laminates attached.
10) Smoke Development
ASTM E84 test method for burning characteristic show that typically EPS has a lower smoke development than XPS.
11) Lower GWP
EPS, the safe insulation, has a lower Global Warming Potential than XPS. Transportation costs are usually lower also lowering GWP.
12) Recycle Accessibility
With over 200 EPS recycling centers in the United States it is easy to see that not only is it 100% recyclable, but it easy to do.
(Learn More about these 12 reasons)
As EPS continues to grow even more popular and gain market share, competitors have continued to spread these old myths. The bad news for them is these myths have been BUSTED. Numerous studies done around the world are proving that EPS is not only “the safe insulation” but that it holds its R-value better, is extremely durable, great in freeze-thaw cycling, has great drying potential and outperforms all other rigid foam insulations.
(Get the 12 Reasons Brochure)
The most popular solution is adding some insulation and retrofitting a new roof membrane over the top. This is were roof insulation Flute Fillers play an important role. Not only do they add R-value to the system but they can transition a flat surface for a new roof retrofit system. I typically see flute filler level with the top of the ribs/seams and one additional layer on top of that smoothly bridging the top of the ribs/seams. The question is can this system be improved upon?
The one area of thermal weakness in this system is where the original metal roof has seams (connection point of the two pieces of metal roof) that allow heat loss at those points. By installing only one layer of insulation over these seams, it allows for the potential of thermal loss at these junctures were the insulation joints meet these metal roof seams. This thermal loss could cause condensation and stress the membrane disproportionately causing future issues.
Some may say, there is insulation under the metal roof system already, those joints don't leak heat. Really? Take an infrared camera and scan that metal roof and look at the seams, you might be surprised what you find.
There are two solutions to fix this potential problem with retrofitting over a metal roof. The first solution is to add another layer of insulation and offset the joints. The second solution is to use Plymouth Foams RetroDeck™ with a cover board. This system has a built in seam offset. No roofing system is perfect, but eliminating as many potential problems can help a roof system last longer creating better value for our customers.
You’re bidding on a project and EIFS (Exterior Insulated and Finish Systems) is specified in the building package. Who do you rely on that it specified, bid and installed correctly? Where does the buck stop?
EIFS has make huge advancements in technology, systems and installation details. The biggest advancement for our northern climates has been drainage or moisture management. Advanced design EIFS systems use a drainage cavity to move unwanted moisture out. This concept is monumental and removes many of the old design flaws with EIFS.
Here is where knowledge can lower your risk and pay off for you. Insist that your EIFS system only uses EPS insulation. Why?
Good building practices and todays advanced EIFS systems' goals are to discharge any stray moisture as quickly as possible. What about when that moisture finds its way into the insulation? Good Question! We know from studies that XPS (Extruded Polystyrene) insulation has a difficult time discharging moisture. Moisture in EIFS systems can cause serious system failures such as cracking, blistering, peeling paint, structural rotting and even mold. EPS (Expanded Polystyrene) insulation, on the other hand, has the ability to breath and release off moisture much quicker. In test situation, EPS also has the ability to hold most of its R-value, where XPS losses 48%.
EPS Moisture management is a great reason to insist on EPS insulation in your EIFS system but here are a few more:
- EPS can be made into a variety of shapes
- EPS can be made in various thicknesses
- EPS can be made in various densities
- EPS offers a consistent R-value
- EPS is the Safe Insulation - no harmful HFCs
- EPS is 100% Recyclable
- EPS is a Better Value and Lower Cost
This is one of those cases where a less expensive product is much better and can lower your risk.
Learn more about EIFS
I noticed this year, Home Depot is making a big deal out of trying to reduce EPS (“styrofoam”) out of some of they're packaging and just substituting other plastics. They think it is great, I think it is foolish. That new packaged Home Depot christmas gift that doesn’t have EPS but cardboard and plastic, where does that packaging end up? After Christmas this year, look though people’s trash and you will discover that much of the paper and cardboard that can be recycled is not. Why? What did Home Depot gain?
Let’s talk about EPS for just a minute. There are recycling centers all over the US just for EPS. In fact, there are over 200 EPS collection centers and growing. Last year in 2016, over 118 million pound of EPS was recycled. That is a ton considering EPS doesn’t weigh that much as 98% of the product is air.
They say, Americans are lazy and we need stuff that is biodegradable to put in the landfills. They don’t think we are smart enough or motivated enough to recycle EPS. I think Americans are smart enough but we certainly could do a better job of educating the public on all these EPS recycling centers. We could do a better job of letting the public know that EPS is a resource rather than garbage. That EPS is 100% recyclable just like aluminum cans. We need to push our local municipalities to add Number 6 to our recycle bins. (Click on the Video below, it is really eye-opening.)
So this Holiday Season, I am adding to the phrase “Peace on Earth” to Peace on Earth and please recycle your EPS.
Learn More Plymouth Foam Recycle Center
Nation Wide Drop Off Centers
Video Recycling EPS
The biggest concern of condensation and its effects can be quit worrying for building owners and construction professionals. Water that forms in a system can cause damage such as:
✓ Corrosion of metal panels and components which can structural weaken the system
✓ Degraded and wet insulation reducing thermal performance
✓ Mold and/or mildew growth that can increase health risks
✓ Insect infestation which can contaminate systems
Condensation tends to occur in noticeable quantities and cause problems at surfaces where there is a sudden change of permeance, which causes an increase in local relative humidity sufficient to create dew point conditions. Condensation in metal roofs can be caused by air leaks around units, holes in vapor barriers/retarders, gaps in insulation just to name a few and no system is bullet proof. “Moisture moves by several mechanisms, including bulk drainage, diffusion (absorption), surface diffusion (absorption), capillarity, osmosis and convection.”
Condensation can occurs on a hygroscopic surface, such as wooden sheathing or insulation, then moisture is absorbed, lowering the vapor pressure and increasing the vapor pressure gradient, driving more moisture toward that surface.
Picking an insulation that is resistant to moisture and help stop condensation is important, but no insulation is 100% waterproof. When Polyisocyanurate (Polyiso/ISO) or Extruded Polystyrene (XPS) gets wet, they dramatically loss their thermal effectiveness. Engineered Expanded Polystyrene (EPS) has the ability to resist moisture but when it get wet has the ability to expel moisture. Most metal roofing systems are not waterproof but rather watersheds. Therefore, air can travel and flow through the upper metal roof system allowing drying to occur. Learn More Here is the Secret: EPS is the BEST Insulation Solution for Metal Roofs because it can expel moisture caused by condensation. EPS's R-value will stay stable and be an overall better value.
View our Metal Roofing Products
Continuous Insulation, is defined as, “insulation that is continuous across all structural members without thermal bridges other than fasteners and service openings.” More important is the fact that Continuous Insulation increases R-value performance due to the non-interruption of wooden or steel studs.
“Furring out” a wall with studs or furring strips and then filling in the gaps with insulation is still a common method used on interior and exterior walls. Every stud used, lowers the R-value and thermal loss and/or thermal bridging occurs at this intersections. Advancement in understanding performance R-value through continuous insulation has lead to the importance of Gold-Wall. The advantage of Gold-Wall is not only a Continuous Insulation system, but it has the built in ability to allow for finishing attachments. These finishing attachments can be interior drywall or exterior clad siding like vinyl or steel. The possibilities are almost endless.
Gold-Wall, with its built in surface attachment stud, can be installed easily to most type of masonry walls. Gold-Wall can also be attached to steel studs, wood framing or even OSB/Plywood surfaces. Gold-Wall comes with a high performance poly facer laminated to the moisture resistant EPS foam board which increases durability, fastener holding and impact resistance.
Gold-Wall may be perfect for your next Continuous Insulation project. Learn More
Foundation insulation may be easy to overlook as many building professionals may be going under to old adage, "if it ain't broke, don't fix it." The serious reality is that in cold weather climates any structure that has a foundation that touch soil such as basements or frost walls needs to viewed differently in regards to moisture management.
Foundation insulation can be used for a variety of reason but the most important is R-Value. This is where it gets interesting - what does Moisture Management have to do with R-Value? Its all about building performance in real world applications.
We can explore permeability and the Laws of Thermodynamics and go very technical but for now most people know that when insulation gets wet, the R-Value of the insulation is reduced. This lowering of R-Value is a performance issue.
A new way to view and understand foundation insulation comes from a moisture study. This study looked at the two most commonly used insulation for below grade - XPS (Extruded Polystyrene - pink or blue) and EPS (Expanded Polystyrene - white). Three relevant items of note come from that study. First, XPS lost about 1/2 of its R-Value below grade and EPS held almost all of its R-Value. Second, it was found and further studied that EPS takes on a little more moisture than XPS but EPS insulation has the ability to dispel it. Third, for some anomaly in physics, that we don’t quite understand, EPS even with moisture, tends to hold its R-value. (Learn More from the research)
So now that we know what happens to insulation below grade how does that all tie back into Moisture Management? If you are not going to 100% envelope or water proof your below grade insulation or below grade wall system, EPS insulation should be used 100% of the time. Remember, the goal of Moisture Management - keeping a building lasting longer and performing properly - Its all about performance. If you want your below grade insulation performing properly and its going to be left “unenveloped," the best Moisture Management choice is EPS.
What if you're a contractor and you want to recycle your foam? Plymouth Foam has a program to help with larger quantities of EPS Foam. (Learn More - How to) Plymouth Foam encourages recycling of construction EPS. "The biggest challenge is educating contractors on how to recycle foam."
Plymouth Foam is working on educating the public that EPS is "the Safe Insulation" and is 100% recyclable. In fact, in 2013 over 34% of post consumer EPS was recycled, that is over 127 million pounds. (Learn More about Why EPS is so Green)
Plymouth Foam Recycle Center
1800 Sunset Dr.
Plymouth, WI 53073
The Ashwaubenon Community and School District faced a dilemma - what do you do with an indoor pool that is over 48 years old and has outlived its expected life? Think “outside of the pool” and fill it in with Plymouth Foam’s Durafill GeoFoam and give new life to the building!
Restoring this aged pool was not a viable option as there were too few of lanes and replacement parts were no longer available. The community decided to build a new pool, but what do you do with the old one?
The building that housed the pool was still in good condition. Filling it in with Engineered EPS Foam and pouring 5” of concrete on top “gives this building a new purpose.” This new area will be used as a commons area with tables and chairs for students to eat lunch.
Like all schools districts, needs change. Filling the pool in with foam has a number of possibilities for the district. Foam can be removed and the area can be repurposed for maybe stadium seating or a performance stage. The possibilities are endless.
Filling in a pool sound easy, but reducing in-fill weights and loading pressures of traditional fills such as gravel or stone can be impractical or unachievable. Geofoam to the resue, however filling in a pool with different depths and various slopes is not an easy task.
Boldt Construction’s design team working together with Plymouth Foam Geofoam Consultant, John Calkins, and was able to offer DuraFill Geofoam blocks that were manufactured in various sizes to fit to the contour of the pool. The pieces were labeled and shop drawings were used to install the pieces. Boldt Construction was the general contractor and they “did an excellant job of making the pieces work and come together.”
Using a local contractor and a local manufacturer has many benefits for the local ecomony. Tax money collected for the school district is being spent locally and benefits from the “local multiplier effect.” This multiplier means the money is recirculated 3-5 times in the local economy and is a key tool for creating more local jobs. The school district saved money on transportation cost since the manufacturing facility is less than 75 miles away - now that is “thinking outside the pool.”
GROWING PRODUCT SEGMENT: EPS
The article, “North America Building Thermal Insulation Market Worth $10.75 Billion By 2025” by Grand View Research states that there will be a growing insulation demand in residential and commercial applications due to the increasing energy costs driving the demand. In 2015, the North America building thermal insulation market was valued at $7.09 billion creating an increase of $3.66 billion over the next nine years.
How can the rising demand for thermal insulation reduce energy costs?
In the sense every building product associated with residential or commercial applications help reduce energy cost; thermal insulation materials assist in reducing heat buildup within the buildings, cutting down on the dependence on air conditioning.
EPS has been a popular product in Europe and now has good attention in North America; expecting to be the fastest growing product segment because of the excellent thermal insulation properties and longer life span. EPS accounted for 23.5% of share by volume in 2015 and expected to increase 1.5% by 2025 (shown in the image below).
Product market share, by revenue (USD Million), 2015 (USD Million)
Having new construction and implementation of energy efficiency codes are likely to result in high industry rivalry perceiving slow but stable growth in the industry.
R-value is more than the R-value per inch. Polyisocyanurate (ISO), starts out with a higher r-value per inch, but then the blowing agents escapes and the R-value is reduced. (learn more) Expanded Polystyrene (EPS) has a lower R-value per inch but can be make thicker to match any R-value requirement. EPS’s R-value increase in colder temperature while ISO decreases. Many would give ISO the edge because of R/inch, but taking into consideration overpaying for R-value that does not stay stable in lower temperature, the advantage has to good to EPS.
- Environmentally Friendly
- Design Flexibility
- Moisture Retention
Expanded Polystyrene, when compared to polyisocyanurate, certainly has more reason to be use in roofing. It seems over the last few years, many designer have lost sight of the purpose of insulation and the importance of R-value long-term. Some designer only considered combustibility and its superior importance, when in all likely hood this physical property will never ever be used. A feature such as long-term R-value, which performs daily in that system, or even moisture expelling capability, get lower considerations. When all of the major features of insulation are considered, EPS seems to be the clear winner.
Wisconsin Lutheran College located, at 88th and Bluemound, in Milwaukee, WI is one of the fastest growing and most affordable college in Wisconsin. With the student body increasing, the need for additional parking was greatly desired.
Wisconsin Lutheran College is nestled between a beautiful Wauwatosa neighborhood and a busy Freodtert Hospital Campus. Designing and building a structure for parking needed to fit into the community and yet be functional. The end result was mentioned by a local official, “this may be one of the most beautiful parking structures in the county.”
Designed by HGA Architure and Engineering, this state of the art, 4 level Parking Center has the ability to hold 350 vehicles. Security and safety was built into the project for the users with an abundance of lighting and a security station. Another great feature to this parking center is the access in is very spacious and it has a two lane exit point for left or right turn functionality. The feedback from students on the additional needed parking has been extremely positive.
One of the real construction challenges in building this Parking Center was the problematic soil conditions that place extremely high lateral loads to the foundation walls. Designing and specifying regular fill material to help these lateral load conditions would take settling and compression time. This extends the project build time and increases cost.
Another challenge to the project was the confined area that was sloping toward the project. Moving heavy equipment and material into the site took careful planning. Weather and construction conditions were managed by a great team of construction professionals from Catalyst Construction.
Plymouth Foam’s DuraFill Geofoam was able to meet the challenge of this project by reducing the construction time line by providing a “ready to build site.” Reducing the build time reduces labor costs and carrying loan cost for the college. Staying on time and on budget for a large construction isparamount in the construction world and DuraFill delivered.
Other fill materials are seldom controlled and can produce varying effects and outcomes. Plymouth Foam’s DuraFill Geofoam is controlled during the manufacturing process and is designed and engineered to accomplish those specific construction outcomes. DuraFill meets the challenge of being an ultra-lightweight material that can reduce load settlement and improve stability against bearing and slope failures.
Breaking away from the norm and thinking out side the box is what Lumber Sales & Products, Jackson, Wisconsin strived to accomplish. Using a wood stove and in-floor heating is beyond normal construction and took special design and engineering.
Instead of using the traditional pink or blue XPS insulation, Engineered EPS was used as the insulation beneath the concrete to dramatically help save energy. Not only does the EPS work better, but the cost savings was almost 30%. The cost savings for just the insulation was over $15,000. In addition, the saving on the supply lines, using EPS, was $7 per linear foot.
Often these types of projects are specified using XPS insulation because of the myth that EPS is not as good or somehow the hot water running through the pex will melt the insulation. The reality is EPS is a far better product in this application and the cost saving is just an additional benefit. Once the merits of Plymouth Foam Engineered EPS systems are reviewed, the substitution is usually welcome and accepted. Read the entire Job Profile
In high school, I remember watching the track team race around the track. One runner Peter, a farm kid, was fascinating to watch as he always grabbed the early lead. Peter always looked so fast but in the end he would typically finish in 3rd or 4th place. In that moment, early in the race, Peter looked like a world class athlete that would easily win gold at the Olympics. In those early moments, that frozen time, the measure of performance was perfect.
Thirty-six years later and I see the same thing happening in the rigid insulation market. Its like watching Polyiso, and XPS insulation running just like Peter, getting off to a tremendous lead regarding R-value, but then fading out at the end. That perfect moment in time is when that R-value gets measured and they look like superheroes but in reality they just “blowhards.” Pardon the pun as the blowing agent escapes and lowers the r-value. (LEARN WHY)
When it comes to below grade or roofing insulation, Polyiso and XPS start out with really good R-value numbers but they don’t last (LEARN MORE). Unfortunately, you pay for these early performance numbers, sometimes as much as 50% more. Paying for performance isn’t bad but not knowing that the product will fade out is a different matter.
The old idiom, “slow and steady wins the race” really holds true in insulation. EPS might start out slow (or lower r-value) but is consistent through its life and ultimately wins the race. Not only does EPS (Expanded Polystyrene) have a steady consistent R-Value but when compared with XPS and Polyiso, it also performs better in the field. XPS and Polyiso, when wet, hold the moisture and loss much of its r-value. EPS has the ability to hold its r-value and even expel moisture under exsiccate conditions.
Next time, when you’re looking to specify or install insulation on a project, remember that Polyiso and XPS look great at the beginning but EPS is the steady performer and the best value in rigid insulation. Your customer deserves the winner - EPS.
When installing a new roof, (new construction or replacement) an owner is faced with the role of Risk Management. Many building owners believe the serviceable life of a roof is directly related to the warranty. Roofing Manufacturers’ have seized upon these beliefs by selling “NDL (No Dollar Limit) Warranties” giving customers the euphoria of total protection. Are NDL Warranties worth it?
NDL warranties have a relatively high cost, at several levels. There is a cost per foot for the warranty and to qualify for the NDL, the “system” has to contain “everything” from the roofing manufacturer (screw, plates, insulation, etc.). Most roofing manufacturers do not make all the components in a roof system but rather put their name on them and mark them up.
This is where NDL warranties go sideways - “all the other components.”
According to Roof Warranty Research, roofs typically don’t fail because of washers or insulation. So if insulation and other components, rarely if ever, cause roof failures, why bundle them into a warranty? Does the NDL warranty guarantee the R-value of the insulation when it declines or gets wet? Would you be surprised if I told you they do not?
Maybe bundling all these other components in a NDL warranty offers better cost? When the Roofing Manufacturers bundles the other components, it ultimately places a double margin on “all the other components” - 1st mark up from original manufacturer and the 2nd mark up from NDL Warranty Roofing Manufacturer. Does this double margin reduce cost or add extra profit for the roofing manufacturer?
Interest fact, the roof installers lose their competitive ability to “shop” all the other roof components, driving the prices higher. So, NDL Warranties really take Value Engineering away from the roofer and the building owner! In reality, it really hampers the free market system in some ways.
So are NDL worth it? It has long been said, that roof warranties are written to protect the manufacturer not the owner and that the best warranty is the one that you never have to use. What is a building owner to do? I suggest saving money and take the advice of the roofing experts, make sure the roof is installed properly, do proper maintenance and faithfully monitor the roof through inspections - this is how you get longer serviceable life, not through a NDL warranty.
Experience in the industry has shown that it takes designers and architects several years to catch up and change their project specifications based on new information. This opportunity window allows for roofing contractors to provide a wonderful service and offer "Value Engineering." (Get a copy of - "Value Engineering Tips and Tricks for Roofing")
The recent research has shown that polyisocyanurate (ISO) insulation provides an R-value of 5 R/inch at 40ºF and 4 R/inch at 25ºF. Contrast that to Type VIII Expanded Polystyrene (EPS) that has an r-value of 4.2 R/inch at 40ºF and 4.4 R/inch at 25ºF. Now, take into account that the cost difference between ISO and EPS insulation. ISO Insulation can cost up to 60% more. This really spotlights EPS as the best r-value/inch value. Substituting EPS insulation in for ISO in a value engineering premise is quite simple as the numbers speak volumes. The real trick is how it can be accomplished in an environment that is so "Pro" ISO?
Ultimately, the building owner can win by saving money and yet the contractor can win by proving his professionalism and closing more work - a real Win-Win.
Early this year, the National Roofers Contractors Association, made a recommendation to it's members that Polyisocyanurate Insulation revise "its design in-service R-value recommendation to 5.0 per inch thickness." This declaration was the second time Polyisocyanurate's R-value was downgraded in the last 2 years. For some of us "Energy Aficionados," who understand the principles of insulation off-gassing, determined it was time to re-examine LTTR testing (View Technical LTTR Bulletin).
LTTR really looks at Long-Term Thermal Performance of insulation as 5 years. Do we expect a building to last only five years? How is 5 years a true quantitative analysis of R-value performance?
We do not replace insulation in a building every 5 years, why would we think that is long-term? Most building in the U.S. are built to last 50 years, some 100 years. Long-term R-value should be figured at 50 years… right? We know off-gassing continues to happen after 5 years. Let's re-evaluate what we are doing as an industry and modify Long-Term Thermal Resistance to at least 50 years.