Brick: Lakeside’s Cornerstone, Part 7 The Roof

by Judy King 11. March 2010 16:09

Whew…who know there was so much to know about bricks? Today we conclude this Seven-part series by taking about the all important roof.

Once all the bricks have been laid in the bóvedas, the masons begin layering the upper surface, to form the top of the roof. This system has been developed over the years to create a waterproof, strong rooftop that can double as a mirador (view terrace) or the floor of the second story.

First is Lechada

The first sealer coating is a very runny mixture called lechada. The workers mix grey cement, sealer and water, and then mop it onto the top of the bóveda. The lechada (milky-looking) liquid runs into all the cracks and crevices to seal the top side of the brick and grout.

Building up the sides; Filling in the spaces

Workers make a small retaining wall two or three bricks high, all around the roof edges, and then fill in the areas between the beams with jal (pea gravel) until the roof surface is flat, and level with the tops of the arches. Next a very wet, loose mixture of jal, yellow sand, cal (powdered lime) and cement is poured over the roof until the retaining wall is full. Small channels are included in the finish work on this layer, to direct the flow of rainwater into downspouts or off the roof onto the garden and away from windows and doors.

Workers carry buckets of the jal mixture up to the roof until a layer 6-8" deep has been poured over the entire roof.

While some of you still North of the border are imagining a ready-mix truck pumping the mixture onto the roof, that's not the way it happens here. Two men on the ground continually stir the concrete mixture and fill five-gallon buckets for the other workers. Those workers carry the heavy buckets up ladders to continually pour the roof. Occasionally pulleys can be utilized to reduce the labor required for the job, and still get enough buckets of the mixture to the roof, quickly enough.

More Lechada and then the tile

Once dry, the jal layer is sealed with another mopping of lechada. Then when the lechada is dry, the masons cover the roof with 8" square flat clay tiles (ladrillo de azotea), laid on a base of concrete.

Sealing and Waterproofing the Surface

Next come two coatings of grey cement mixed with sealer and water, followed by a finish sealer. This could be a commercial product called Fester, terra cotta or white sealer—and because of the difference it makes in the way the roof repels water, you should know the difference between the types of sealers and know which your contractor is using. .

When this sealing process is done well, the job can be guaranteed for five or six years. If it is done very well, with top quality materials and best sealers, the roof should be waterproof for about  10 years, maybe longer, although due to the effects of the sun and heavy rains, a simple additional sealer coat should be applied after four or five years.

Special thanks go to General Contractor Juan Gilberto Higuera and the maestros of The Little Company in Ajijic who explained procedures to me, answered questions and provided technical information for this article.


Judy King is publisher of Mexico Insights—Living at Lake Chapala, a monthly online magazine for people interested in Mexico's Lake Chapala region, in the state of Jalisco.

Judy, a 19-year resident of Ajijic on Lake Chapala's north shore, conducts weekly newcomer's seminars and shares her expertise about Mexico in her ezine at www.mexico-insights.com, and in the "Mexico Lindo" column of the Lake Chapala Review.

Judy also is a speaker for local organizations and visiting tour groups about the Lakeside area about Mexican customs and holidays.

Brick: Lakeside’s Cornerstone, Part 1

by Judy King 3. March 2010 12:11

brick-and-mortar-wall

Quality construction at Lake Chapala begins with a stone foundation and red brick walls which are strengthened with interlocking upright and horizontal steel-reinforced castillos (hand-made concrete beams).

While the brick boveda ceiling/roof structure is readily visible to homeowners, the material used inside the plastered walls of their homes is not as apparent. Given the opportunity to make the choice, I’d select ladrillo (fired red brick) rather than locally produced bloque (hand-poured, solid concrete block) for the walls of my home.

Mexico Insights Note: You can see bloque being made in an open field just above Doñas Donas in Ajijic. Forms are placed on the ground and filled with concrete. After a brief setting-up period, the forms are removed and the blocks cure in the sun.

We’ll talk about how bricks are made in local brickyards in tomorrow’s post. Those are the brick being sold from the line-up of huge trucks near the Ajijic Cemetery. It may surprise you to see how those bricks are loaded into the contractor’s truck for delivery to your house.

Workers throw stacks of five bricks (each weighs about a pound) bucket brigade-style from the huge truck to the delivery truck. At your house, the process is reversed as workers throw the bricks from one to another to bridge the distance from the truck to the stack of bricks they are keeping in reserve for the job.

 throw-bricks good-catch

(Left:) A worker stretches to catch the stack of five one-pound bricks that is thrown to him. Did you notice that the bricks separate mid-air and you can see spaces between them, making the stack even harder to catch? (Right:) Surprisingly, as long as the rhythm of the throw and catch are maintained, workers seldom drop any of the bricks.

What’s the Difference between ladrillo and bloque?

Developers producing homes for sale in a development and individuals building “spec homes” (homes built for profit, with the intention to sell them during the construction process or shortly thereafter) often build with concrete blocks. The blocks are less expensive to purchase than brick and because they are larger, it takes less labor and less mortar to construct a wall.

Blocks can be used to create a wall that is strong (if the builder includes several rows of bricks after about three feet of block height). If the developer cuts corners and uses only one or two rows of brick instead of three or four rows, or saves brick and money by waiting until the wall is four or five feet tall, the strength of the wall can be compromised.

While the quality of the finished home can be affected by the use of brick vs. concrete block, my biggest concern is with the insulating quality of the two materials.

Keeping Warm in the Winter and Cool in the Spring Heat

North of the border homes are insulated as they are built, and additional insulation is added to older houses. You’re familiar with the need of insulation to help keep the house warm during the cold months and cool during warm times.

Its very different in Lake Chapala-built homes. With no attics, crawl spaces or hollow walls, we depend of the building materials to insulate us from the more moderate climate here – and choosing the right one (along the best alignment of the house for cross breezes and direct sunlight) can make a big difference in the temperature inside your house.

1. Adobe. The best insulating building material of all is old-fashioned adobe. While I only know of one home built from hand made mud adobe in the past 15 or 20 years, I’ve lived in two old homes where most of the walls were adobe covered with plaster.

2. Local Brick. Locally made and fired traditional brick insulates very well. it can be even better if the walls are build in the old-time method, making them 1.5 bricks thick. Bricks are readily available, made from local deposits of clay, and are reasonably priced.

3. Concrete Block. Concrete block is nearly always used for locales (small storefronts in strip mall-like buildings), other commercial buildings and in cheaper construction.

How are these natural clay bricks are made? How is the process different from bricks made in Europe hundreds of years ago or in Canada and the US in the past two centuries?

Next -- Brick: Lakeside’s Cornerstone: Part 2  Making Bricks

brick-trucksLearn the ancient process of making and firing bricks

Then -- Brick: Lakeside’s Cornerstone, Part 3 Making Arches

How are arched windows and doors constructed?

And  --  Brick: Lakeside’s Cornerstone, Part 4 Domes and Vaults

Learn about the domes that crown many local homes in the old Moorish style the Spanish brought to the new world in the 1500s.

Ahhh  -- Brick: Lakeside’s Cornerstone, Part 5  Boveda

Ah, the key to making those arched ceilings so common at Lake Chapala. How do they do that?

And Then – Brick: Lakeside’s Cornerstone, Part 6 Brick Designs

See the variety of designs that used in side walls, boveda or domes…and learn the names. This is a valuable reference piece.

To Wrap up the series, there’s a Bonus Post – Brick: Lakeside’s Cornerstone, Part 7 The Roof

After all, the whole point of that strong boveda, vault, arch or dome is to create a safe, dry roof over the living area of a house. See what happens next.

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Judy King is publisher of Mexico Insights—Living at Lake Chapala, a monthly online magazine for people interested in Mexico's Lake Chapala region, in the state of Jalisco.

Judy, a 19-year resident of Ajijic on Lake Chapala's north shore, conducts weekly newcomer's seminars and shares her expertise about Mexico in her ezine at www.mexico-insights.com, and in the "Mexico Lindo" column of the Lake Chapala Review.

Judy also is a speaker for local organizations and visiting tour groups about the Lakeside area about Mexican customs and holidays.

About Judy King

Judy King

Hi There — Welcome to my little corner of the world. I'm Judy King and I live in the centuries-old village of Ajijic on the north shore of Lake Chapala, Mexico's largest natural lake.

I've lived here full time since 1990, and... [ more ]

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