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Focus on Roofing: Adhesive and Sealant Products used in the Installation of Clay and Concrete Roof Tile

Posted on 11/13/2012 3:02:19 PM By Bob Braun
  

 roofing, building, construction, Ancient Greek Clay Roof Tiles

Figure 1: Ancient Greek Clay Roof Tiles 

This blog continues the ASC Building Products series for roofing which began with ASC Blog #10. Now we will move from the subject of low-slopped roofing into roof tile.  This specialized application is largely residential and light commercial buildings with slopes greater than 2:12 in pitch.  The concept for this building material goes back many centuries using clay but now has evolved in recent years with concrete tiles dominating while many even newer products have also entered the market that are designed to look like either clay, concrete, or slate tiles.  Some of these product types will be featured in this blog as well.  The newest products can be made from many different materials that are generally pressed or molded from metal, plastic and composites while ceramic tile is also in common use now.  The use of tiles is often based on an architectural desire to achieve a certain appearance that is compatible with the building design, geographical region, and neighborhood and, is generally considered a premium look.  Thus asphalt shingles are now made to imitate at least somewhat the look of the historical roof tiles.  In general roof tiles have been more popular in Europe and the South, West, and Southwestern USA as well as South and Central America. 



 Roofs, Germany, Beaver Tail Style Tile, roofing, building, construction, adhesives, sealants  spanish style roof, roof, texas, roofing, building, construction, adhesives, sealants
 Figure 2: Roofs in Germany with Beaver Tail Style Tiles Figure 3: Ceramic Spanish Style Roof in Texas


First, let us look at the basics of a tile roof assembly.  The Tile Roofing Institute illustration below shows the basics for one recommended assembly for a moderate climate.



 tile roof assembly, tile roof, roofing, adhesives, sealants, building, construction



Figure 4: THE BASICS FOR A ROOF TILE DECK ASSEMBLY

 

Due to the many local variations and codes the above details can vary considerably.  In some cases vertical battens and cross battens are used and in other cases no battens are used.  However, in each case, tile installation requires a water proof membrane that may be attached to the roof deck by various methods.  Some membranes will utilize a factory applied adhesive and tile may be secured using a polyurethane foamed adhesive that will be described further below.  The foamed adhesive entered the market in the 1990’s and is gaining popularity with both one and two component systems in use.  These products attach the tile directly to the adhered or nailed membrane and to the batten as well. 

Historically, tile has been installed with two or three nails at the top edge of each tile.  With no attachment at the lower edge, however, high winds can lift and displace tiles from the roof.  The foamed adhesives provide attachment at top and bottom thus resolving this problem (view web links below).

 

 roofing, adhesives, sealants, roof, building, construction  roofing, adhesives, sealants, roof, roof installation, building, construction
 Figure 5: A Non-Foamed Adhesive for Roof Tile
Figure 6: Batten and Cross Batten Installation


The use of sealant in tile roof assemblies is similar to other roofing types.  The Tile Roofing Institute provides the following general guidance: Caulking and sealants shall be suitable for exterior use and be resistant to weathering. The caulking and sealants shall be compatible with and adhere to the materials to which they are applied.  Vents and protrusions such as plumbing stacks shall be flashed or sealed to underlayment with a membrane compatible sealant to prevent water from passing into the attic space.


Here are several links to the use of foamed tile adhesives -

Two Component Foamed Adhesive Application

One Component Foamed Adhesive Application on a Medium Profile Tile

One Component Foamed Adhesive Application on Flat Concrete Tile



 roof tile, roofing, adhesives, sealants, building, construction  





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Figure 7: Some Roof Tile Types
 Figure 8:Metal Tile Design to Simulate Clay Tile Profile


NOTE:  There are three basic profile types (low, medium, high) for roof tile that predicate what the code requirements will be and how the foamed adhesive will be positioned on the tile or substrate...more on this in my next blog.


In Blog #16, I plan to detail the several code and interesting test requirements for the foamed adhesives that are used in tile roofing.  As with low-slopped roofing as discussed in Blog #’s 10-14, Roof tiles are tested as an assembly and wind uplift resistance is a key criteria…as usual.



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