Ask a TRI Expert

Ask a TRI Expert: Roof Protection with Tiles & Underlayment

Have you ever wondered what types of questions people “Ask a TRI Expert“? This series, brought to you by the Tile Roofing Institute, allows anyone to ask anything about tile roofing installation, maintenance, etc. The Tile Roofing Institute (TRI) is a non-profit association of producers and associates of concrete and clay tile and is considered one of the leading experts in the industry. Here’s a recent question from a homeowner repairing their concrete tile roof, and the response from TRI President and Technical Director, Rick Olson.

Question:

“Recently during Hurricane Matthew a few of my Spanish style concrete tiles were damaged, cracked with some pieces missing. When the roofer showed up to repair the roof I was told that the tiles were only cosmetic and the real roof protection is underneath. I’m sure water gets under the tiles but I would think that most of the protection is from the tiles-70% or more. What is the truth about these roof tiles?”

Response:

“Historically (early 1900’s-1960) tiles that were installed were generally handmade or from home style manufacturing machines. With the low roof pitches in Florida, the wind driven rain could be allowed to enter the roof system, so the concept of a fully sealed roof system was used. 30-pound roofing felt was installed and a hot mopped 90 lb. cap sheet was applied. The tiles were then installed to prevent the UV from breaking down the underlayment.

Fast forward to the tiles made after about 1965. They were manufactured with newer high speed machines utilizing European technology that made a very dense tile that would prevent water intrusion through the tile (permeability) and allow tiles to become the primary water shedding component. In Europe, they were actually installed for centuries without any roof sheathing or underlayment, until recently.

The use of the sealed underlayment under the tile in Florida has continued over time because it provides a very good secondary barrier in the event there is either wind driven rain, or damage to the tiles during an event.

In summary, you are correct in your thoughts, but the stories passed down to roofing contractors carries the old thought from when tiles were not made to the newer standards. That said, there are still imported tiles that may not meet the requirements for permeability. All of the producing members of TRI will meet the criteria. If consumers choose to use an imported tile, we caution them to read and ask if the imported tiles will perform as the code requires.”

If you have any questions regarding concrete tile or installation, the Tile Roofing Institute’s website, www.tileroofing.org, is a great resource. TRI also offers installation certification courses throughout the United States, so be sure to check their course schedule to register for one in your area!

Please feel free to contact your local Eagle Account Representative with questions or visit our website at www.eagleroofing.com.

ASK A TRI EXPERT: TITLE 24 AND TILE FASTENING

Have you ever wondered what types of questions people “Ask a TRI Expert“? This series, brought to you by the Tile Roofing Institute, allows anyone to ask anything about tile roofing installation, maintenance, etc. The Tile Roofing Institute (TRI) is a non-profit association of producers and associates of concrete and clay tile and is considered one of the leading experts in the industry. Here’s a recent question from a homeowner repairing their concrete tile roof, and the response from TRI President and Technical Director, Rick Olson.

Question:

“I have a contractor who is trying to meet Title 24 requirements on a new project. They are asking about installing 1/2″ Polyiso insulation over the roof sheathing before applying 2-layers of 30# felt and concrete S-tile.

We have never installed insulation this way. It seems that having to nail the tile through the insulation to get to the plywood sheathing would detract from the holding strength of the nails. Can you let me know if this would be acceptable to install a tile roof with this system or do they need to find another way to meet their T-24 requirements?”

Response:

“As you have identified, title 24 does create some challenges for the roofing professional. In essence there are prescriptive and design options for meeting the requirements that include the building design, A/C, lights windows and roof systems. For tile, they have generally been met through using higher solar reflective colors that have been formally rated by the Cool Roof Rating Council (CRRC). The air space above the sheathing called the Above Sheathing Ventilation (ASV), will also increase the thermal barrier and has an R-value in the equation. With some designers, they are trying to maximize additional benefits by looking to add thermal radiant barriers either above or below the sheathing. In your case they are trying to add insulative board above the sheathing.

The challenge is that such materials are not code approved substrates for our tiles to attach to. The fasteners would need to be of sufficient length to penetrate 3/4” into the actual sheathing. We call these pre-engineered systems and look to the manufacturer of the insulation board to provide proper fastening requirements.

As the tile industry, we have done extensive uplift testing on traditional fasteners into plywood, but do not have testing to support the use with Polyiso style of insulation materials. We have raised our concerns to the California Energy Commission to look beyond just the radiative properties and review the actual installation requirements for wind, fire, and seismic code requirements as well.

I hope this helps answer your question. I know it is a little more detail than required, but it helps show the challenges we are facing as the Title 24 raises the thresholds.

In summary, we do not have a formal installation detail for the installation you are referring to. The local building official may have established criteria for use, but would suggest you ask the designer to call out the length and size of fastener they would require. The best result would be to just use tile and if they wish additional levels, use a radiant barrier underneath the sheathing.”

If you have any questions regarding concrete tile or installation, the Tile Roofing Institute’s website, www.tileroofing.org, is a great resource. TRI also offers installation certification courses throughout the United States, so be sure to check their course schedule to register for one in your area!

Please feel free to contact your local Eagle Account Representative with questions or visit our website at www.eagleroofing.com.

Ask a TRI Expert: Repairing a Tile Roof

Have you ever wondered what types of questions people “Ask a TRI Expert“? This series, brought to you by the Tile Roofing Institute, allows anyone to ask anything about tile roofing installation, maintenance, etc. The Tile Roofing Institute (TRI) is a non-profit association of producers and associates of concrete and clay tile and is considered one of the leading experts in the industry. Here’s a recent question from a home inspector, and the response from TRI President and Technical Director, Rick Olson.

Question:

“We are repairing our roof and I had two estimators. One said that he has to put cement on every tile. The other said no cement on tile because in cold places in winter it will crack the tile. Please let me know who is right and who is wrong.”

Response:

“In general tiles are currently fastened with nails, screws or adhesive foam. Mortar has been used in the past, but does have some challenges due to the physical properties of the mortar. A brief summary is that the density of the mortar will be different than the density of the tile. The expansion and contraction of the materials will be different and can create cracking or separation of the bonding of the tiles. In areas subject to freeze thaw, the moisture in the mortar can expand when frozen and crack the mortar. In most areas, when mortar is used, it is for the aesthetic effects such as adding an additional lift (boost) to the tile. In the Southeast (Florida) the use of mortar was in place for many years, but the effects of long term exposure to expansion and contraction did not allow the proper bonding to meet the new high wind code requirements and has been replaced with the use of Foam adhesives.

Location and climate conditions will impact the preferred method for repair. If you let us know where you are located we can provide more specific recommendations.”

If you have any questions regarding concrete tile or installation, the Tile Roofing Institute’s website, www.tileroofing.org, is a great resource. TRI also offers installation certification courses throughout the United States, so be sure to check their course schedule to register for one in your area!

Please feel free to contact your local Eagle Account Representative with questions or visit our website at www.eagleroofing.com.

Ask A TRI Expert: How to Navigate the High Wind Tables in the TRI Manual

Have you ever wondered what types of questions people “Ask a TRI Expert“? This series, brought to you by the Tile Roofing Institute, allows anyone to ask anything about tile roofing installation, maintenance, etc. The Tile Roofing Institute (TRI) is a non-profit association of producers and associates of concrete and clay tile and is considered one of the leading experts in the industry. Here’s a recent question from a home inspector, and the response from TRI President and Technical Director, Rick Olson.

The high wind tables in the Tile Roofing Institute’s Concrete & Clay Roof Tile Installation Guide can be intimidating at first glance. A recent “Ask the Expert” response by TRI President and Technical Director Rick Olson describes how to use the tables to determine fastening requirements.

Question: 

“Oklahoma is considering changing to a 115mph wind zone. I need help to decipher the tables in the back of your TRI manual so to know how to use these on an install.”

Response: 

Although they seem onerous at first glance, the wind tables are not too harrowing to navigate with a few clues.

If Oklahoma is considering the 115 MPH designation, we will assume they are going with the 2012 IBC/UBC and the tables in Appendix C would apply. Since most tiles are installed on Gable/Hip roofs we would be looking at Tables 9A (roof slopes 5.5:12< 6:12), Table 9B (roof rlopes 2.5:12<5.5:12, shown below) or Table 9C (roof Slopes 6:12< 12:12).

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Table 9B

This will let us know what the wind uplift would be on the tiles. Since you are 115 MPH, you would use the 120 MPH column for exposure C (most commonly used outside of coastal areas).

*Example: 5:12 hip roof at 25-ft. mean roof height, exposure C is 13.4 ft-lb of resistance (from Table 9B). 

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Table 9B – Exposure C Example

Now we need to go to Table 7 on page 85 (since Table 2 on page 95 only has the very high wind options that are above your 120-mph cutoff).

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Table 7 – Page 85

Here we list all of the fastener options and their corresponding resistance. You need to select the tile profile. So let’s say a flat tile on a batten on a 15/32” sheathing.

We need an option that will exceed the 13.4 so we will be looking at the 1-#8 screw at as a minimum with 25.6 in Table 7.

Table 7 Choices with Battens
Table 7 Choices with Battens

If you were a direct deck application with a 15/32” sheathing, you could use the 2-10d smooth shank as a minimum with 20.2

Table 7 – Direct Deck – Page 84
Table 7 – Direct Deck – Page 84

Can Chlorine be Used to Clean Mold Off of Roof Tiles

Have you ever wondered what types of questions people “Ask a TRI Expert“? This series, brought to you by the Tile Roofing Institute, allows anyone to ask anything about tile roofing installation, maintenance, etc. The Tile Roofing Institute (TRI) is a non-profit association of producers and associates of concrete and clay tile and is considered one of the leading experts in the industry.

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An extreme example of unchecked moss and tree debris on a 30-year roof in a cool, humid climate.

Most Roofing Contractors are well aware that one of the most common inquiries from customers is how to clean a tile roof. Here at Eagle Roofing Products, we always suggest contacting a certified professional to make sure the job is done safely and properly and refer to the Tile Roofing Institute’s maintenance guidelines.

Below is a recent question submitted to TRI’s “Ask the Expert” form and the response from TRI President and Technical Director, Rick Olson.

Question: 

“Can chlorine be used in conjunction with pressure washers to clean mold/algae from roof tiles?”

Response: 

The cleaning of tiles with pressure washers is a common practice as regular roof maintenance. Since roofs are slippery when wet, the work should be performed by a qualified roofing professional. We recommend professionals do not use a pressure setting above 1300 psi to avoid damaging the surface of the tile. While the use of diluted chlorine can be used to help remove the final algae that might be present, plain water can be just as effective in clearing unwanted growth.

Any dirt, algae or moss that may grow on the surface of the roof tiles are not affecting the condition of the tiles or their ability to protect the structure. It is more an aesthetic issue that customers may wish to remove. While HOA’s or other governing entities may require regular cleanings, they are not necessary to maintain the integrity of the product.

Ask a TRI Expert: Cracked Tiles

Have you ever wondered what types of questions people “Ask a TRI Expert“? This series, brought to you by the Tile Roofing Institute, allows anyone to ask anything about tile roofing installation, maintenance, etc. The Tile Roofing Institute (TRI) is a non-profit association of producers and associates of concrete and clay tile and is considered one of the leading experts in the industry. Here’s a recent question from a home inspector, and the response from TRI President and Technical Director, Rick Olson.

Question:

“I recently inspected a home in that was being sold by a real estate agent who was also the homeowner. There were a number of cracked concrete roof tiles that I observed. The buyer asked me what type of repairs needed to be performed and I told him the only acceptable repairs, according to the roof tile manufacturers, was to replace the broken tiles and that gluing them back together was considered only a temporary “patch.” The homeowner/agent called me after “repairs” in the form of gluing the broken tiles back together was performed and was told by her licensed roofing contractor with 40 years of experience that this was a totally acceptable repair and now she is very upset with me telling the buyer otherwise. Thoughts?”

Corner chips like this can be glued.
Corner chips like this can be glued.

Response:

The repair of a broken tile is always an important topic to the roofing professional and does not have a one-size fits all answer. The key is to identify what the broken area represents. As the TRI, our members rely upon the formal codes and local building code official approvals to determine the appropriate steps for a minor repair. In the case of a broken corner that may be about 1-2”, the use of a concrete compatible adhesive may be used. This practice is often used at the transitional flashing areas where a small piece of tile may be needed to complete the aesthetic look. The use of adhesives or wire will help hold the small piece in place. It is also used when a few tiles may have a small broken corner.

 

This tile should be replaced.
This tile should be replaced.

In the case where damage to the tile was created from a load or impact that has created a full vertical or horizontal break the entire width or length of the tile, the use of adhesive is not recommended. These tiles should be replaced. The benefit of concrete and clay tile installations is the ease with which broken tiles can be replaced. In many applications where battens are used, only the perimeter tiles are attached and therefore sliding the upslope course and lifting out the broken tiles will allow for their replacement. Even when tiles are fastened, the broken tiles can be easily removed and the replacement tile secured back in place without disrupting the balance of the roof. This will ensure the ability to return the roof to its pre-damaged conditioned.

For more information on the Tile Roofing Institute or to “Ask a TRI Expert”, click here: http://tileroofing.org/resources/ask-expert/

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