The roofs on dwellings protect all building materials installed below them as well as the personal possessions of the homeowners, and it is wise to invest as much as necessary to install a quality roof system.
Finished roofing products, such as clay tiles and metal laminates do not prevent water infiltration. The proper installation of quality sheathing, a waterproofing underlayment and flashing materials are vital for the durability of a roof.
In order to complete a quality roof installation, compatible components must be specified, purchased and installed according to the manufacturers proprietary specifications.
This presentation illustrates how I installed a quality roof system on an 8000 sq. ft. custom home in Santa Ana, Costa Rica.
I began by constructing a sturdy structure to support the weight of quality roofing components. I used 4″ x 4″ and 4″ x 6″ x 2.38 mm gauge square steel tubes to assemble the trusses.
The steel structure was welded together to provide maximum strength. I used 2″ x 6″ x 2.38 mm gauge rectangular tubes for the long spans and 2″ x 6″ x 1.50 mm gauge steel rafters for short spans
We clean and then paint all steel tubes with two coats of anti-corrosive paint. I use red zinc oxide for the primer coat and white fast dry for the finish coat, in order to see any areas where the coverage is thin
Fascias are welded to the ends of the rafters to support sturdy gutters. I used 2″ x 4″ and 2″ x 6″ x 1.50 mm gauge steel tubes to make the metal fascias
Wide metal flashings insure that no water infiltration will occur in the valley’s. I installed 24 gauge galvanized metal laminates in the valley’s where a lot of water and debris from trees need to pass without obstructions
For sheathing I used 4″ x 8″ x 22 mm thick cementitious laminates and attached them to the rafters with 2 ½” screws. Sheathing is installed with a 1” overhang to allow surface water to drain into the gutters that I attach to the fascias under the overhanging sheathing, to prevent water from entering behind gutters
Cementitous laminates provide a smooth sheathing surface to apply a primer and membrane underlayment. The cementitous laminates do not warp when exposed to moisture like plywood and OSB boards
Metal flashing seals the gaps between the sheathing laminates. I fabricated wide flashing from 24 gauge galvanized metal and installed the custom formed laminates on all ridges
A water diverter in front of the chimney prevents accumulating water from causing damage. This type of flashing installation requires experienced tradesmen that understand this type of custom installation
Flashing was installed on top of the deck and into the vertical walls that meet the roof and a groove is cut with a cement cutting blade into the vertical walls in order to recess the metal flashing
The same type of flashing was installed into the vertical walls of the chimney
Stucco plaster and roof tiles cover the flashing and prevent water infiltration where walls meet the roof
I primed the roof sheathing with a polyurethane sealer to prep the surface before the underlayment is attached
Once the sealer dries, we apply an SBS waterproofing membrane to the sheathing.
The 4 mm thick underlayment membrane is heat welded with propane torches to seamlessly cover the roof surface
Vertical metal counter battens were attached to allow water to flow under the horizontal battens and roof tiles and into the gutters.
Additional waterproofing membrane was installed on top of the vertical counter battens to prevent water from entering under the screw holes
We installed another layer of 1”x 2”x 1.50 mm gauge tubes horizontally on top of the vertical tubes with 2”screws. The horizontal metal battens on top of the vertical counter battens will support the roof tiles
SBS membrane is attached to the fascias below the sheathing overhang. When gutters are screwed into fascias, the membrane acts as a vapor barrier, preventing excessive rainwater from entering above or behind the gutters and inside the soffits
I had 26 gauge gutters fabricated in the color to match the roof tiles. These additional gutters in the valleys under the roof tiles are screwed into the metal battens, and above the waterproofing membrane underlayment to provide a metal surface for rainwater as well as debris from the trees to pass between & under the tiles and into the gutters below
Clay tiles were then placed on roof for installation.
These are Riviera roof and ridge tiles that arrived from the El Aguila factory in Mexico, and they were screwed into the horizontal metal battens
Clay tiles were cut to fit into the valleys , where surface water as well as debris from the trees can drain between and under the tiles, and down into the metal valley gutters
Tiles were installed on the ridges with cement to seal the gaps on the ridges while maintaining a traditional appearance
Large 15” deep x 10” galvanized metal gutters were installed on all fascias, using 2 mm thick steel brackets with upper metal supports screwed into the 1″ x 2″ metal battens
6” wide downspouts were fabricated from 26 gauge galvanized metal laminates, and the installation of the ample downspouts completed this quality roof system.
If you have any questions, or would like to schedule a roof inspection, you can contact me by clicking here