Frequently Asked Questions

Building Envelope FAQ:

1. Q. What kind of glass should be used in this building?

A. Depending on the building size, locality and the number of glass units in the building the basic recommendation for energy savings would be insulated glass units with a Low-E coating. This is a good starting point but products will also be chosen based on construction budget and climatic conditions dependent on whether the building is located in the northern or southern United States. High- Performance glass is available in many colors and degrees of reflectivity which determine performance in the building. An experienced HCI glazing consultant can assist by recommending the top-quality manufacturers and meeting with their area glass sales representative to help determine the proper glass meeting project requirements.

2. Q. What is the proper aluminum framing for the building?

A. This will depend on the type of building and the size of building because many systems are offered today that can be used for different projects.  For instance, one story retail projects would need a different system than a thirty-story high rise. Also the location will determine the type of system since many coastal areas now require hurricane impact systems and the northern areas would require thermally improved or thermal separators systems. With an experienced consultant on your side, meet with an aluminum framing manufacturer representative or a reputable glazing subcontractor to determine the proper system for the local area and type of building to meet your requirements.

3. Q. Is the hardware compatible with the storefront entrances?

A. This is a very good question and a difficult one to answer since the variety of hardware has gotten more technical over the past ten years.  With the electrical security systems and electrical fire safety systems available today the difficulty level has increased tenfold.  Many glazing contractors get trapped on this issue and end up doing extra work fabricating access holes and even wiring hardware from the storefront door to an electrical source of some kind so other contractors can connect their systems.  Coordination meetings with our experienced team before construction will help solve many of these issues and help sub-contractors plan for what everyone needs to accomplish.

4. Q. Is the exterior of my building watertight?

A. Some storefront, window and curtain wall manufacturers ignore the surrounding materials and how the waterproofing ties into the glazing system because they are selling only their products. This may result in water infiltration if attention to the sealant compatibility with the waterproofing is not recognized or if the waterproofing does not connect to the glazing systems framing.  Drawing reviews from our waterproofing experts before detailing and installation can help reduce these risks.

5. Q. What sealant should be used in the exterior of the project?

A.  A neutral cure silicone with a twenty-year warranty is the first recommendation for most surfaces.  Some projects may require urethane sealant because of bonding issues or large joint sizes but today’s neutral cure silicone will usually be the sealant of choice. Our team makes good sound advice on sealant applications and types to address your project specific needs.

6. Q. The stucco wall is cracking on the front of our office. Is this going to be a problem?

A. Micro fissures that aren’t noticeable 10 ft. away from the wall are generally not a problem. Larger cracks that can readily be noticed from 10 ft. away shouldn’t be a moisture intrusion problem if there is a properly installed moisture barrier over exterior sheathing and a weep mechanism. However, freeze-thaw damage can occur where it snows and moisture intrusion is likely if a properly installed moisture barrier is missing. Ultimately, if the Building Owner or Architect are not satisfied, the stucco installation is problematic.

7. Q. Which is better for exterior sealant joints, urethane or silicone?

A. Unless the joint is to be coated or immersed, HCI recommends neutral cure silicone sealant for satisfactory long-term sealant performance. UV exposure can deteriorate urethane sealant within as few as three to five years in southern states. Up to twenty-year warranties are available for neutral cure silicone sealants.

8. Q. Do we need a vapor barrier in our wall system?

A. Interior temperature and relative humidity differences with outdoor ambient temperatures and humidity are among determining factors. Other factors include the use of vinyl wall covering on exterior walls and impermeable coatings. HCI welcomes consulting with you to adequately address the specifics of the anticipated wall system.

9. Q. Which are better, vapor barriers or air barriers?

A. Vapor barriers and air barriers should be considered distinctly different wall systems. Vapor barriers are non-breathable moisture barriers that stop movement of all forms of moisture. Air barriers serve the specific purpose of stopping free air movement into a wall cavity or interior. Air barriers control air flow and vapor barriers control water vapor flow. Air barriers can provide continuous water protection and air tightness.

10. Q. What is the best waterproofing system for our new plaza deck?

A. The best plaza deck waterproofing system depends on a number of factors including the complexity of the plaza and the installer’s experience with the waterproofing systems under consideration. Hot applied rubberized asphalt waterproofing systems minimize the likelihood for installation deficiencies but cost more than some of the more labor intensive membrane systems. Cold process systems have improved significantly and with cost constraints are well worth consideration.  Thermoplastic sheet waterproofing can be cost effective and provide many years of satisfactory performance.

11. Q. How can we learn if our windows or our walls are leaking?

A. HCI offers visual condition surveys and non-destructive moisture surveys with infrared thermography and dielectric capacitance. We also perform simple water spray testing with nozzle spray and chamber water testing. When the above procedures are inconclusive we also perform invasive surveys with boroscopes.

12. Q. What can be done to stop the water entry into our basement?

A. Removing fill, exposing the positive side of the wall, applying a waterproofing system including a drainage mechanism and back filling is the surest way to stop water entry. If logistics prohibit such an invasive scope two other options include capturing the water and taking it to a sump pump or waterproofing the interior wall. Interior wall waterproofing can include a cementitious slurry or a breathable coating system.

13. Q. If we’re installing Dens Glass Gold exterior sheathing, why do we need a separate moisture barrier?

A. A moisture barrier, such as 15# felt, has been required since International Building Code 2000 to create a drainage plane directing water out of the wall cavity. With the proper moisture barrier installation, water entry into the interior is minimized and problems with missing disbonded tape on sheathing joints are avoided.

14. Q. What is the best roofing system for my facility?

A. HCI recommends multiple layer waterproofing roofing systems when the budget is adequate. Hot applied coal tar pitch, asphaltic felt and both APP and SES modified bitumen BUR roofs can be expected to perform well for twenty to twenty-five years with qualified installers and proper installation technique. Properly designed and installed metal roofs can be expected to perform well for over thirty years. Fully adhered and mechanically attached single ply roofing may be valid options to address Energy Star criteria and difficult flashing configurations. HCI emphasizes life-cycle costs analysis for selecting a roofing system within initial and maintenance budgets.

15. Q. How do I know I’m getting a quality contractor?

A. System manufacturers and consultants can pre-qualify quality contractors. While manufacturers have a direct interest in seeing their select contractors on the project, an independent consultant can assist the Owner to obtain the best market competitive bids.

16. Q. Why do I need a building envelope consultant?

A. An experienced objective consultant can identify problems and deficiencies in a timely manner and can offer cost-effective remedies for the correction of deficiencies and for the completion of the work. An independent consultant serves as an Owner Advocate to assist designers and constructors to obtain satisfactory performance with minimal expected maintenance.

17. Q. How do I know if the contractor is doing a good job?

A. While site visit quality control inspections performed by a knowledgeable manufacturer’s representative have some merit, project quality in the building envelope system installation is best ensured by observations and condition reporting performed by an independent objective and experienced consultant. Work to remedy deficiencies is tracked and documented best by a knowledgeable fee-based Owner Advocate that isn’t dependent upon the system installer for their livelihood.

18. Q. Do I need to select barrier EIFS or drainage EIFS?

A. HCI recommends drainage EIFS systems covered by a manufacturer’s 10-yr warranty.  The weak link in the barrier EIFS system is the sealants. Very few building Owners schedule, budget and implement replacing failed sealants before damaging water entry occurs.

19. Q. Which is better, EIFS or stucco?

A. Stucco can offer longer expected performance with less maintenance but historically is initially more costly and may not accommodate accent bands, cornices and other wall offsets as well as EIFS. HCI recommends the creation of a drainage plane behind EIFS and stucco installation and the corresponding weep mechanism.

20. Q. What is the difference between a water repellent and a sealer?

A. A water repellent is not to be considered a waterproofing sealer but like its name a water repellent repells water entry into the substrate by penetrating and filling voids. Water repellents are breathable or permeable. After application most water repellents are undetectable. The service life of water repellents varies greatly. A sealer can be a waterproofing application and in lieu of penetrating into the substrate, a sealer generally forms a waterproof film on the substrate. Sealers are non-permeable and most create a sheen or darker appearance substrate.

21. Q. Our brick walls just started leaking. What’s changed and what do we need to do?

A. HCI would need to perform a building envelope survey to comment on the specific water entry mechanism. A roof leak could have developed. Wall sealant joints could be deteriorated and failed. A water repellent that was working may have UV heat oxidized and may no longer be functional.

22. Q. Our company has two warehouses side by side and the only difference is the roofing system. One building has roof leaks or condensation and the other building doesn’t. What’s the cause for the problem and what can be done to stop the water problem?

A. HCI consultants have been confronted with this scenario where one warehouse has a mechanically attached single ply roofing system with thermal bridging at fasteners permitting condensation. The other roofing system was a ballasted EPDM single ply roofing system without condensation issues. Adding a foam-type insulation board and ballast on the first roof solved the condensation problems. If the structure couldn’t take the weight of ballast, another lightweight reflective single ply membrane or liquid applied roofing would need to be installed over adhered insulation on top of the mechanically attached roofing installation.