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Tile Installation Manual
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If you followed the directions for installing a high quality underlayment, you
should have an excellent base upon which to install the roof cover of your choice.
For tile roofs, the accepted US reference for proper installation in high wind
areas is the Florida Roofing, Sheet Metal and Air Conditioning Contractors
Association / Tile Roofing Institute guidelines document, Concrete and Clay Roof
Tile Installation Manual Fourth Edition FRSA/TRI 07320/08-05. These guidelines
are recognized by the Florida Building Code as the guide for installing tile roofs.
The underlayment options described in this guide are consistent with two of the
options outlined in the FRSA/TRI Guide.
Generally, tile roof anchorage requirements are based on results of testing
and engineering calculation. Uplift coefficients for a particular roof tile
shape and thickness are determined for wind tunnel tests and this information
is used to determine fastener sizes and numbers of fasteners for mechanically
attached tile and paddy size and location for either mortar set or adhesive
set tile installations.
We do not recommend the mortar set option for attaching tiles. A study by
tile experts suggested that there were more than 30 ways that the mortar set
technique can go wrong. Fortunately, mortar set tile installations represent
less than about 1% of new tile installations in Florida. FEMA suggestions for
tile installations in high wind areas also do not recommend the use of the
mortar set system for attaching tile roof covering (see
FEMA Tile Roofing for High Wind Areas).
The keys to good mechanical installations include making sure that the right
number and sizes of fasteners are used. The fasteners have to have an adequate
head size to keep the tile from working over the head of the fastener during
buffeting by winds in a hurricane and the withdrawal capacity of the fastener
has to be great enough to keep the fastener from pulling out of the roof deck.
For adhesive tile installations, the key is to make sure that enough adhesive
is applied in the right place under each tile (paddy size and paddy location).
The requirements for fastener size, number of fasteners, paddy size and paddy
location are all dependent on the design wind speed and the particular tile
being used. Each manufacturer has installation instructions for their tile
for various design wind speeds.
The main changes that have been incorporated in tile installation guidelines
coming out of damage assessments following the 2004 and 2005 hurricane seasons
are enhanced requirements for attaching ridge and hip tiles (typically barrel
shaped tile that are installed over the edges formed where different slopes of
the roof intersect to create an edge that sticks out from the rest of the roof.
The new guidelines require that a board or metal hat section be securely fastened
to the roof along all ridges and hips and that the ridge and hip tiles be securely
fastened to these boards or metal hat sections. These revised guidelines for
ridge and hip tiles are being incorporated into the Florida Building Code effective
the end of 2006.
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Metal hat sections installed on hips
and ridges for anchorage of hip and
ridge tiles
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Note that despite the presence of the
metal hat section attached to the hip
edge, the tile were not in contact
with the adhesive that was supposed
to anchor the tile to the hat section.
(click image for larger version) |
Because the hip and ridge tiles as well as the eave tiles are frequently the
first tiles to break loose in high winds, regardless of whether they are
impacted by debris or not, it is recommended that these tiles be installed
with extra care and attention to detail. One way to help assure better
performance of eave tiles is to have the roofer attach them as if the roof
were to be installed in a higher wind zone. For example, if the manufacturer's
installation recommendations for your area was to install a single nail, the
roofer could go to two nails for the eave tiles, if the tile has holes for the
second nail, or to a screw instead of the nail, or add a clip at the bottom of
the eave tile that anchors it to the fascia board. Similarly, for the hip and
ridge tiles, the roofer could use both mechanical fasteners at the top of the
tile and adhesive near the bottom of the tile to create a stronger anchorage
for these more vulnerable tiles.
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You can check specific product approval information for a particular tile
at the
