View Full Version : Clay Tile Installation questions

Jeff Eastman
07-12-2007, 07:07 PM

Jerry Peck
07-12-2007, 08:07 PM
Would you agree that:

1- Nails are underdriven?
2- The nail holes should be sealed?

First photo? No.

3- Headlaps nead mastic or appropriate sealant?

First, and more importantly, those are rake tiles used for the ridges. Those should be ridge tiles.

Ridge tiles do not have holes along their sides, they have holes top center. Typically (depending on you wind zone conditions), yes, the ridge tiles need to be "properly" fastened down. This normally means that the ridge tiles are fastened to a nailer below the ridge tiles, and the overlap end of one ridge tile (this is the "headlap") is glued to the end of the tile below, this is the tile with its 'head lapped', i.e., "headlap", (the end which faces up the roof and which is nailed or screwed down) with roof tile adhesive. NO OTHER TYPE IS ALLOWED, only "roof tile adhesive". Ohio Sealants is the first, and major, manufacturer of roof tile adhesive, their RT 600 adhesive (RT for Roof Tile). "Headlap" consists of two tiles, one is overlapped (the bottom tile) and one is underlapped (the top tile), with the distance of the overlap being the "headlap".

4- Lead flashing should overlap next adjacent tile crown?

Not required. That flashing is shedding water over the tile which has the vent penetrating it, now it is just like the tile itself over the tile below.

Now, that photo with the hip ridge tile, and the three plumbing vent stacks, well ... THEY ARE JUST PLAIN FLASHED WITH THE WRONG flashing. :D

The other flashing in your photo was an 'on top of the tile' flashing, indicating this roof is a System One ... ALL the flashings should be 'on top of the tile' types.

Besides, those on those three vent stacks, they look a lot like Type B vent roof flashings, not plumbing vent flashings, and not for a System One tile roof either.

Jerry Peck
07-12-2007, 08:43 PM
Okay, I'll probably regret this latter - eating humble pie - but Jerry I disagree on some of your assessments.

- If you zoom into Jeffs' 1st & second photo, the nails are underdriven.

Nope. Any tighter (or at least much tighter) and those nails will break the tile. Those nails are not as critical as the nails holding the field tile in place. Each rake tile should have two nails, one covered by the next tile up on the rake.

- Manufacturer installation guideline states that the lead flashing skirts to extend to the adjacent tile crowns. The guidelines specify 18 inch lead skirts to assure that skirt extends over top of adjacent tile crowns.

In that case, you got me on that one. Please quote it for me.

I think you are reading it incorrectly. I suspect it means that the lead skirt goes up under the tile above.

But, I am ready to be corrected if you quote it here so we can all be on the same page.

- The nail holes on the ridge tiles need to be sealed.

Nope. Those ridge tiles are rake tiles, they NEED TO BE REPLACED with ridge tiles, and then the hole will disappear.

- The overlap of tile for hips and ridges need sealing.

Nope, that is not for "sealing" purposes, it is for "holding down the tile butt end" purposes. That is why "roof tile ADHESIVE" is required.

I await your quotes to show me my errors, open to learning, but you need to post the quote or page of the installation instruction your information is from. Post it as a .pdf file, that works well.

Richard Rushing
07-12-2007, 09:55 PM
Clay tiles are not suppose to be nailed flush, typically left 1/8-1/4" raised.


Martin lehman
07-12-2007, 10:49 PM
Those are not clay tiles, they're concrete.
First photo, the underlayment should overhang the rake edge 1" min.
The hip and ridges are not weatherblocked.

Jerry Peck
07-13-2007, 07:19 AM
Those are not clay tiles, they're concrete.
First photo, the underlayment should overhang the rake edge 1" min.

The installation instruction manual is referring to this only for single layer underlayment systems, i.e., System One installations. I am 'assuming' that the installation shown is a System One because 'some' of the flashings are 'on top'.

In the first photo, if you can tell that the underlayment is not overhanging the rake, you've got better eyes than mine (and I must say, mine are not as good as they used to be).

The hip and ridges are not weatherblocked.

This is not referring to where one tile laps over another tile, "weather blocking" is where the spaces between the hip/ridge tile and the field tiles below are pointed up with mortar. When you lay the ridge tile down (for example), its straight edge rests on the profile of the tile below, and, with anything but smooth surfaced flat tile, there will be gaps and spaces between the field tile and the ridge tile (the same for field tile and hip ridge tile). THOSE gaps and spaces need to be "weather blocked", which is almost always done by pointing up with mortar.

This is what it states: "Openings at hips, ridges and head walls including chimneys, skylights, solar panels, and downslope horizontal abutments shall be fitted with weather blocking material to keep water on the surface of the field tile. Other methods approved by local building official will be allowed. See Technical Bulletin at www.roottile.com (http://www.roottile.com). Wrapping of nailer board is optional except with the use of mortar." (I.e., as in 'mortar set' installations.)

Did you catch the "of nailer board"? How many time do you find that installed?

NOTE: The above is from the 2002 installation manual. (The 2004 instructions treats the last part above the same as the 2002 instructions.)

The 2004 installation manual does not show the 1" overhang over the rake. The "optional" drip edge at the eaves in 2002 are now not shown as "optional", they are just shown, and, in fact, in the installation instructions, it states "Drip edge metal shall be installed at the eave, over the sheathing" (for single ply systems, i.e., System One).


On another note, the 2002 installation instructions state that those 'flashings on top of the tile' are to extend (to the side of the pipe being flashed) a minimum of 4" on flat tile and a minimum of 1" past the crown on profile tile, i.e., 1" over the top of the profile so the water drains down the other side of the profile tile, not back to the penetrating pipe.

In the 2004 installation instructions, the flashing is shown as covering a much larger area, the installation instructions state "Apply skirt flashing over last field tile cut previously installed extending under the course of the tile above the penetration. Insure flashing is of sufficient width to redirect the water away from the penetration". The drawing states "Make watertight seal between pipe and underlayment", which, of course, you should not be able to see.

Martin lehman
07-13-2007, 09:01 AM
I own the 2002 and 2006 TRI manuals and both require felt to extend over the rake edge min 1"
Unfortunately I do not have or know of a 2004 manual.:(

Jeff, you need to visit Tile Roofing Institute (http://www.tileroofing.org) and get the installation manual for moderated climate regions.

Martin lehman
07-13-2007, 08:08 PM

Not Jerry, but maybe someday :D

Jerry Peck
07-13-2007, 08:16 PM

Nope is correct. :)

Well ... you did say "can", and those rake tiles "were", so the real answer to your question is 'yes'. BUT the answer to the correct question of *are rake tiles ALLOWED to be used for ridge tiles*, the answer is NO. :D

Jerry Peck
07-14-2007, 08:42 AM

Sounds like you are describing System Two, Three, or Four installations.

System One installations have the flashings on top of the tile and are the worst (and cheapest) installations for tile roofs.

My guess is that you are seeing better installations, maybe even the good 30/90 hot mop systems. That's good. With those, the weatherproof covering is the 30/90 hot mop, the tile is then used to protect the weatherproof system by keeping most of the water off it, by protecting it from sunlight, weathering, debris, etc.

Why they install System One tile roofs is beyond me. The *tile cost* is the same, the *tile installation cost* is the same, all they have done is save a little on the underlayment, which means throwing away all that good tile much sooner. The true cost of a System One installation is greater than a 30/90 hot mop as the replacement cost comes much sooner for a System One (unless you are in an area where it does not rain).