Air Date: 2-14-2020|Episode 574
This week on Iaq Radio+ we welcome John T. Hull. John has over 25 years in the roofing and coatings industries. He is a recognized authority on roof restoration and moisture detection within the roof and building envelope. Mr. Hull has provided technical support, training, and consulting in over 30 Countries. His expertise in roof restoration has contributed to roofing projects at NFL stadiums, airports, universities, hospitals, military bases and even the White house.
“Introduction of the Moisture Mob”
Roofs, Moisture Meters, Inspections & Solutions for Leaks:
Lessons Learned from an industry Veteran.
John T. Hull is a recognized authority on roof restoration and moisture detection within roofs and building systems.
Among list of projects he’s worked on are NFL stadiums, airports, universities, military bases and even the White House, where he and his team provided technical guidance and consulting when the National Park Service wanted to restore a section of the White House’s roof.
John T. Hull is a former roofing contractor with 13 offices across multiple states. He then worked for roofing products manufacturer in sales and technical department inspected 1,000s of roofs. The last several years he has been an independent consultant to: architects, contractors, material manufacturers and building owners.
Nuggets mined from today’s episode:
- Due to ice dams, hailstorms and hurricanes, insurance companies are involved in many roofing claims.
Types of roofs
- All types of roofing are used in the residential market. Shingles are the predominate roofing system inn residential. Shingles shed water and are not waterproof. Flat roofs are popular in the southwest. Metal accounts for 20% of new residential roofs especially in coastal and areas prone to wildfires.
- Popular prior to the 1990s, built-up roofs add 3-5 layers of felts, asphalts/tars. They provide redundancy. Use is declining due to higher labor and material costs and overall weight.
- In the 1970s modified bitumen roofing became popular. Using a base sheet and a cap sheet asphalt was either mopped on or torched on.
- Beginning in the1990s there has been explosive growth of single ply membrane roofs such as EPDM, TPO and PVC. EPDM is the same material used in tire innertubes. Single ply roofs are a one-layer membrane installed over 1-2 layers of insulation adhered with adhesive or a fastening system. Seams are heat welded. These single ply roofs provide no added redundancy but are more resistant to ponding water than asphalt roofs.
- Vegetative/garden roofs are very costly and environmentally appealing.
Lifespans of roofs
- Geography is an important factor.
- Shingles- 20-30 years
- Built-up roofs-30+ years (depending on UV exposure)
- Metal, tile, & slate- lifetime roofs 100 years.
- Modified bitumen- 20-30 years
- Single ply membrane- 15-20 years
Frequency of roof surveys
Recommends that a roof moisture survey be done periodically every 3-5 years and following weather events such as hailstorms and hurricanes. When moisture penetrates the roof system it can cause additional damage through material degradation and corrosion.
General Roof Inspection– is a visual observation and evaluation of the outermost roof surface, laps and flashing. Visual inspections should be conducted at least once annually.
Roof inspection process needs to be consistent & repeatable.
- Must understand the building use.
- Must understand the type of roof.
- Awareness of influencing factors (cold storage, overhead cranes, thermal shock, building movement). Matching buildings may conceal differences (such as: skills of roof installation crews, materials, etc.)
- Walk entire roof noting and marking visual problems.
- Calibrate instruments and equipment.
- Establish dry standard and then survey the roof.
- Mark problem areas with paint.
- Sketch and overlay Google earth.
- Create accurate diagram, notate position of drains, HVAC equipment, etc.
- Applicable ASTM standard is driven by type of surveying instrument.
Roof survey– a “medical approach” which determines what is going on underneath and within the roof system. Use inspection instruments (infrared camera, Tramex® impedance meters (deck scanner & handheld), moisture meter, and nuclear roof scanner, drones, aircraft).
Deck scanner penetrates 4”-6”. Verification is done with moisture meter and pin probes.
Nuclear gauge isotope penetrates 8” and searches for hydrogen as a moisture indicator.
Verify findingswith destructive core testing where indicated. Information and findings are plotted on a map in the report.
A roof survey can morph into a building envelope survey where the building envelope is examined holistically. Moisture problems may be caused by parapets, windows, walls, etc.
A full service moisture survey provider needs all the tools.
Recommended triggers for a roof survey.
- Prior to roof replacement. Underlying wet materials must be dried or replaced prior to installation of a new roof.
- Following installation of a new roof, a roof survey documents the new pre-loss condition of the roof.
- Prior to restoration. Roof restoration involves fixing seams, flashings and applying a coating can significantly extend the lifespan of a roof. A recent survey done prior to a roof restoration found that 46% of the roof was wet. The survey averted a massive roof failure.
Ballast rock is used on built-up and single ply membrane roofs. Built-up roofs flood the roof with melted asphalt and then spread in ballast. The ballast prevents UV penetration and reduces flame spread.
Ballast holds single ply roofing in-place.
Houston and other hurricane/high wind zone cities are outlawing ballast due to projectile damage during hurricanes.
Roof Survey Pricing
Large wide open roof systems offer economy of scale (4-5 cents per sqft). Complex condominium buildings are more difficult and time consuming (20 cents per sqft). 10-20 cents per sqft would be a reasonable range.
- Roofs should be designed to shed water.
- Roofs with high foot traffic are most prone to leaks.
- Roofs with less redundancy are more prone to leaks.
- Geography is a big factor: UV light and extreme weather.
- Roof materials offer uniform quality.
- Installation skill varies.
- Ponding takes a toll, abrasive soil and biological degradation.
- Parapets may be aesthetically pleasing.
- Parapets can cause uplift.
- Parapets, when not sealed, capped or treated can act as sponges. The taller the parapet the greater the potential for problems.
- Expansion joints and sealers.
Roof Asset Management- annual inspection, cleaning, replacement of sealants.
A good roof surveyor needs to think like a water and a building scientist.
3 phases of a roof:
Repair- during which deficiencies are fixed.
Restoration phase- during which an encapsulate or coating is applied to extend life.
Replacement – The most expensive and invasive option.
The roof covering is what is exposed to the elements. Construction waste from roofing tear-offs is the major waste disposed of in landfills. 2/3’s of roofs can be repaired and revitalized.
Pete Consigli- Restoration Industry Global Watchdog
- Water damage restoration is rooted in the flooring industry.
- The guiding principles of the Moisture Mob: Truth and accuracy in moisture measurement or face the consequences. Excess moisture in buildings adversely effects: IEQ, comfort, health, personal property & building materials.
- Controlling moisture serves the greater good.
- Upcoming Moisture Mob episodes: Hardwood Flooring from Treetops to Roots, Sports Flooring Confidential, A Flooring Inspectors’ Stories from the Darkside.
Tips for Floridian’s searching for an honestRoofer:
- Make sure they are licensed.
- Verify they have insurance.
- Verify they are partnered with good manufacturers.
- Verify they are Certified Installers for multiple manufacturers.
Want to learn moisture surveying and roof inspection?
American Roofing Educators
169 Griffin Boulevard Unit 115,
Panama City Beach, Florida 32413, United States
Z-Man signing off
Name the ancient Roman festival from which Valentine’s day evolved?
Answered by: Vic Cafaro
Roofing Industry Trade Shows
International Roofing Expo – https://www.theroofingexpo.com/en/home.html
Western Roofing Expo – http://westernroofingexpo.com/
Florida Roofing and Sheet Metal Expo – https://www.floridaroof.com/convention/
New England Roofing Contractor Association Show (NERCA) – https://nerca.org/event/nerca-2020-convention-trade-show/
RCAT – Texas Roofing Conference – http://roofingcontractors-texas.com/tradeshow/
Midwest Roofing Contractor Association Conference (MRCA) – http://www.mrca.org/aws/MRCA/pt/sp/conference