Forums > Specific Focus > Home, Garden & Construction in Mexico

tony

Nov 19, 2007, 8:11 PM

Post #1 of 14 (4081 views)

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Water Seepage Question - Roof

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Hello,

In our newly constructed house we are seeing water seepage through the roof. Is there
a way to simply seal the whole roof ? It is your typical low pitch cement roof. The water
doesn't seem to be sitting up there either.

Sincerely, Tony

"We don't see things as they are, we see things as we are."

Rolly / Moderator

Nov 20, 2007, 5:41 AM

Post #2 of 14 (4066 views)

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Re: [tony] Water Seepage Question - Roof

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A low pitch concrete roof needs to be sealed. Here is the way we did it on my building project. Look the bottom of the page for the start of the process http://rollybrook.com/12-07.htm and here for the finish http://rollybrook.com/01-03-02.htm

Rolly Pirate

robrt8

Nov 20, 2007, 8:17 AM

Post #3 of 14 (4052 views)

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Re: [tony] Water Seepage Question - Roof

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Home depot and most all the hardware/paint shops I've visited carry elastomeric paint/sealers for the roof. Costco sells Sherman William's "Home Cover".
It comes in white and terracotta. It's rolled or sprayed on. Should be really easy over your newer roof.

Esteban

Nov 24, 2007, 6:22 PM

Post #4 of 14 (4010 views)

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Re: [tony] Water Seepage Question - Roof

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One of the best methods of sealing a roof in Mexico is to tile it. Use a light colored tile to reflect the heat. If done right, you won't have to screw around with sealing anymore.

jreboll

Nov 25, 2007, 7:26 AM

Post #5 of 14 (3990 views)

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Re: [Esteban] Water Seepage Question - Roof

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The tile also serves as an insulator

robrt8

Nov 25, 2007, 10:12 AM

Post #6 of 14 (3974 views)

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Re: [jreboll] Water Seepage Question - Roof

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Are you guys talking about a pitched roof? If you're talking about a deck, you'd have to do use a system like Rolly's and tile over it. I estimate that would last a gazillion years or so. Tile alone will not stop water penetration.

jreboll

Nov 25, 2007, 12:15 PM

Post #7 of 14 (3966 views)

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Re: [robrt8] Water Seepage Question - Roof

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The roof on my house is flat poured concrete. Tile was was placed to give the roof runoff. In more than 15 years we haven't had any roof leakage. As I said, this also helps as an insulator.

robrt8

Nov 25, 2007, 6:07 PM

Post #8 of 14 (3943 views)

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Re: [jreboll] Water Seepage Question - Roof

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That's amazing. I don't know how that can work. Do you think they may have put some kind of membrane under the tile?
I have an unsealed concrete roof. Unless there's a downpour, it doesn't leak. I imagine the water that works its way down in an average storm evaporates off the surface. There's plenty of scale.

Esteban

Nov 25, 2007, 7:57 PM

Post #9 of 14 (3931 views)

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Re: [robrt8] Water Seepage Question - Roof

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Ceramic tile isn't porous. Plus, the "thinset" you use, if done correctly, will have additives that will make the roof even more impervious to water. If you are using a modern thinset, it's a polymer based stuff that is more impervious to water than concrete. Then, if you do a good grout job and seal the grout WELL, you have a much better chance of the roof not leaking. A pure concrete roof is very porous and must be treated once a year in rainy climates. Some will say that impermabeable <-sp? will last five years but on the west coast, but south of the Tropic of Cancer that's BS.

Even with a concrete roof, many people will use a membrane along with a special mixture of like marble dust, cement and some other stuff. If you have a "pure" concrete roof, which I doubt unless you live in the desert, then you will have leaks. It's just a matter of time.

tony

Nov 27, 2007, 7:36 PM

Post #10 of 14 (3889 views)

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Re: [Esteban] Water Seepage Question - Roof - Cost

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Hi all,
Thanks for the responses. I was hoping for something that is a little cheaper. Tile
or the way Rolly described is going to cost at least a few thousand dollars? I like both ideas though.
I think I have at least a 2000 sq ft of roof. Anyone have luck with the industrial strength
impermebilizador?
Tony

"We don't see things as they are, we see things as we are."

robrt8

Nov 27, 2007, 8:07 PM

Post #11 of 14 (3887 views)

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Re: [tony] Water Seepage Question - Roof - Cost

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Is "impermebilizador" elastomeric paint? I think so. A good part of Mexico is using this stuff. I think it's the same thing. In the most extreme case, it'll buy you a few years or more. I'm very interested in tile because I want to make a deck on my roof. But $$$...

mkdutch

Nov 29, 2007, 10:05 AM

Post #12 of 14 (3854 views)

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Re: [robrt8] Water Seepage Question - Roof - Cost

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Good suggestions all - but since nobody has mentioned a major problem (shifting soil and resulting hairline cracks), here's my 2-bits: The geology of much of Mexico is still active, especially in the Lake Chapala area. Having owned home(s) there since 1999, we've had a lot of experience dealing with both low-pitched and flat boveda-ceiling roofs, which were well-constructed with roofing tiles, fibreglass (Fester brand) sealant-impregnated and sealed impermiable coatings. Good foundation and all the rest, but the ground continues to move, which causes fine cracks to open up each year. Overlaying the cracks with the fibreglass cloth and re-sealing with impermeable (doesn't matter whether it's 3, 5, or 7 year-"guaranteed"), only gives you a one to two Rainy-Season fix. One house was 11 thru 18 years old during our experience and had no more than a few 1/8 inch wide (most smaller) interior cracks - solid, but the structure continually moved back & forth (not down the mountain...;o)...).

IMHO, if your structure is set on this kind of soil, the only lasting solution is to place a flexible, rubberized mat over the entire roof and cover it with material to minimize sun damage to the mat. (the mat referred to is the type often used in USA built-up roofing systems that are set and covered with hot tar and granular rocks) Or place an interlocking lightweight waterproof tile roofing system over the existing structure (available Lakeside), as has been suggested by another poster on this forum. Not a cheap solution, but the conventional roofing techniques used in the Lakeside area just don't seem to have lasting value. Buena Suerte, Dutch

jreboll

Nov 29, 2007, 3:53 PM

Post #13 of 14 (3833 views)

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Re: [mkdutch] Water Seepage Question - Roof - Cost

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Don't forget the foundation. A good solid foundation will avoid many structural problems for years to come.

mkdutch

Nov 30, 2007, 9:08 AM

Post #14 of 14 (3804 views)

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Re: [jreboll] Water Seepage Question - Roof - Cost

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I didn't (see 3rd sentence, above). But even the best efforts sometimes are not enough to overcome unstable soil; about a block from our 1st Lakeside home, a home was built near the crest of the hill, where 4feet deep by 2 feet wide stone foundations were placed under every interior and exterior wall -even under small closet walls. Unfortunately the soil was fill, dumped there when a road was carved up the hill. Even before construction was complete, large cracks started appearing in both the interior and exterior walls. The owners have been fighting the problem ever since.