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In my travels across CR(limited tho they may be) I’ve admired the local architecture in its many versions, observing that roofing materials (corrugated metal, corrugated fibre, clay tiles, stamped metal phony clay tiles, molded plastic phony clay tiles, steel standing seam) are often used on low pitch roof structures, inviting leakage troubles when the rains come. Rain like I’ve never seen!
So, here’s the question to those of you that have gone down this path: what’s the ideal roof material for a modest 150m2 home (in Nicoya, Guanacaste)that’s readily available in CR, having the best combination of benefits: durable, sealable, quiet in rain, flexible with seismic movement, long life, low cost/M2 and ease of proper installation by your neighborhood Tico craftsmen? A roof I won’t have to goof with for the next 20 years? Tell me I’m not dreaming.In the long run, I think the least expensive and least troublesome roofing you’ll encounter is the corrugated sheet roofing by Metalco. It comes with a lifetime guarantee on the finish. Installed correctly (with a double-corrugation overlap and a bead of silicone), it should be permanently watertight.
We had a problem with windblown rain being driven upwards under the “botagua”, the right-angled metal “trim” that forms the fascia on the roof edge and overlaps the sheet roofing on top. That was finally resolved by the installation of an additional sheet of metal about eighteen inches wide to extend the botagua farther over the top and side edges of the roofing. If I ever do a roof again, the botagua will have a much wider overlap over the corrugated roofing material.
Sound insulation is a matter of what you put under the metal roofing. There is a fairly effective product that consists of two external aluminum foil layers with a thin layer of plastic foam between. Or you can use conventional foil-faced fiberglass insulation in thicknesses from about one inch to maybe as much as six.
We’re the rental managers for the house next door. It has an ultra-cheapo metal roof that is supposed to look like clay tile. Everyone says that product is very difficult to make watertight and that’s certainly been our experience.
It is a wise decision to seek the most suitable roofing products, not the most cost effective.
THE SECRET OF A WELL-SEALED ROOFING INSTALLATION – Once the metal roofing system has been properly installed; all components should be covered with at least two coats of a quality roofing paint. The paints surface should be inspected annually to make sure it is still intact and that the screws are still tight. If you maintain this roofing paint, which is thick and covers all metal components, humidity will not be able to enter your roof.
You may find the Inspection/Construction section on WLCR helpful.
https://www.welovecostarica.com/members/department62.cfm there is an article about roofing in CR. https://www.welovecostarica.com/members/1743.cfm?sd=62.
David’s experience is the real deal and his recommendations are sound. The botaguas (the right-angled metal “trim” that forms the fascia on the roof edge and overlaps the sheet roofing on top.) and cumbrera (ridge cap) should be oversized and the outside metal piece angled down to be flush with the surface of the corrugated roofing laminate. Adding a bead of flexible silicone under the flashings is another preventative method of keeping driving rain from entering under the flashings.
Additionally, I have seen with my own eyes, two-inch metal roofing screws; unscrew themselves as a result of metal laminates moving, during one seasonal change. Most people do not understand that metal laminates respond to temperature change just like wood, by expanding and contracting. This causes the fastener holes size to increase, resulting in leaks. Dark colors will experience the largest thermal movement.
According to the manufacturers of metal roofing laminates, panels installed over Metal Perlin should not harm the roof system with thermal movement. However, I can tell you from personal experience that the manufacturer’s installation recommendations, of attaching the metal laminates directly to a Metal Perlin structure, with screws provided by the manufacturer, still expand, contract and move.
Here in Costa Rica, over the last 15 years, I have seen driving rains attack roofing installations, vertically and horizontally. The wind blown rain can be forced under roofing laminates and tiles as well as flashing and drip edge installed on the facias of buildings. If adequate underlayment and flashing have not been installed, thousands of dollars of interior installations as well as personal possessions can be damaged.If you want to apply one of the finest waterproofing sealers to your roof, Thermotek MAX 7 is available in CR for $125.00 per five-gallon bucket. Two coats is the recommended application and each five-gallon bucket will cover about 20 m2 with two coats.
http://www.grupothermotek.com/clientefinal/index.php?option=com_content&task=view&id=32&Itemid=48Thank you all. I knew that tapping the knowledge base available on this site would yield results! We hope to be building within a year; details like this can reduce the number of hiccups and make the outcome even better. And “muchas gracias, amigo” to Scott for this valuable forum. Fred
Hi Postalx,
I found this link online that provide listing of roofing manufacturers.
http://www.thomasnet.com/nsearch.html?cov=NA&which=prod&what=roofing&navsec=search&heading=69112209
I hope this help for some of the questions that you have.
Thank you.
Joseph
Here are a few things I would recommend for your roof. Make sure it has an overhang. For some reason, folks in Guanacaste are butting their tile against walls and using metal flashing to keep the water out. In Nicoya this won’t work. You need a overhang of at least two feet completely around the perimeter of your home. If you don’t need them, don’t use gutters. They fill with leaves often and if they aren’t cleaned by the time the rain comes, the water will back up.
A 4/12 pitch is perfect and looks good to. If you are serious about a no leaky roof be sure to read CRbuilders explanation about how the screws make big holes. I would do it this way. Have your local Tico handy fellow strap your framing with treated 1X3 lumber. Then place 18 guage zinc roofing on top of the strapping. Make sure they set the screws without damaging the seal on the screw. They like to tighten these tight. The idea is to just set the washer so it seals the hole. Do this first part as if it were going to be your final roof.
When that is completed, place that same type of treated 1X3 strapping over the zinc. Install the colored metal roofing. On the colored metal roofing you will see a spot the manufacturer has marked. The screw goes where it’s marked, on the side of the metal roofing material. When you look at the roofing you’ll see what I am talking about.
What you accomplish doing it this way is that there is no area on the roof that can leak, ever! Even when the screw holes get big, no leaky. The screws you placed on the first layer of zinc are on the top side of the corrugated metal, screwed into the 1X3 strapping. These screws are completely covered by the second metal roof. Water can never get to them. The final metal roof has the screws going into the side of the corrugated metal. When those holes get big in the future, the water will leak thru, ending up on the first layer of metal, running off your roof, instead of into your attic or ceiling.
You can go with one layer of metal roof and use as much sealer and silicon as you want. Eventually your roof will leak. For an extra 800 bucks you have a roof that will out live you.
Remember to vent your attic and roofing system. Normally this isn’t done in Guanacaste. Big mistake. I put fans to move the air in my attic taking the air from the ridge of the roof and shooting it out the soffit area. Works like a charm.
My neighbor has a new house and the contractor put the same type of tile they used B.C.. They moved out on Sunday because every area of the roof is dripping, some places running with water. Do it right the first time and it’s done for ever.
Good luck
The recommendations of vbcruiser are insightful and would work well if installed according to his explanation. Accomplishing this using the local workforce will be challenging, unless you are an experienced and hands-on supervisor, all day, everyday, during the construction process.
Many of us have heard the phrase “mind over matter.” I believe this concept promotes using your common sense and experience to overcome matter, such as building materials that may or may not be available here in CR. Many ideas sound good, but implementing them down here in the jungle can be frustrating. With the cultural and language differences, many foreigners become frustrated when trying to communicate their desires to the locals.
Vbcruiser has obviously overcome the typical cultural and language barriers and certainly has been very helpful to point out practical solutions to locally accepted construction methods. He would be an excellent builder for your home and hopefully he will be available for consulting work in Guanacaste.
However, many folks do not have the advantage of having an experienced hands-on supervisor from the real world to assist them with their local construction projects. Here in CR, and especially in Guanacaste, you need to take into consideration the capabilities of the available local laborers. Getting them not to torque down roofing screws into the laminates so the washers do not get damaged is a full time job.
The phrase “if you want to get the job done right, do it yourself” comes to mind. Since most folks cannot do it themselves, and Costa Rican construction continues in spite of its deficiencies, I have searched for practical solutions, so the average person can overcome the differences between international construction standards and those construction standards understood and practiced by the local laborers.
In the absence of an experienced handyman, just about anyone can apply a thick liquid waterproofing product over the top of metal roofing components. You can first clean the roof with an old broom and a regular garden hose with a high pressure nozzle. Then with a normal, thick paint roller, apply several coats of the highest quality waterproofing product you can afford, on top of all your roofing components. If you are able to climb a ladder in order to view your roofs surface, you can decide for yourself when your roof will need another application. If not, you can use binoculars to inspect your roofs surface and keep your home dry all year round.
This posted in the wrong place and reposted here ….
Posted Aug 29,2008 7:00 PM muesquere
Many thanks for all the input, especially from CR homebuilder, we’ve also been carefully considering your postings on roofing tips. We’ve decided to limit the use of almendro to our second floor master bedroom and use tile everywhere else. The almendro we are using is being imported from Nicaragua. Again, this forum is invaluable, thanks to Scott and all contributers.
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