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

Rolly / Moderator

Dec 8, 2002, 8:14 AM

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House Project Update for 7 December 02

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We closed the access hole in the east wall, thus making the job site secure without the need for a night watchman.

The plaster work continues slowly. The plaster guys are working another job at the same time as ours, so they are dividing their time. Not a real problem, they are not holding us up on anything.

We began the process of sealing the roof. This turns out to be more involved that I had expected. More on that on the web site.

The cabinet maker is well under way with his work.

This was Christmas bonus week (2 week's extra pay), so the guys went away very happy on Saturday. I made a Christmas card with my Santa picture and put it in the pay envelopes. Lots of good laughs!

Click here for this week's pictures: http://rollybrook.com/12-07.htm

Rolly Pirate

keith

Dec 8, 2002, 8:33 AM

Post #2 of 14 (2562 views)

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Re: [Rolly] House Project Update for 7 December 02

We only have one small cement roof at our place. I had to re-tar it recently. We've tried a bunch of differnt paints on it, and the best that I've found so far is a really heavy coating of "sno-roof."

Dec 8, 2002, 9:50 AM

Post #3 of 14 (2564 views)

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Re: [Santa] House Project Update for 7 December 02

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Thanks Santa for the year-round gift of your weekly website entries. It really is different construction techniques than stateside, and I'm both enjoying and learning a lot (almost like those books and "educational" gifts which got neglected on Christmas day, but eventually got a whole bunch more mileage than the toys [well, there was that chemistry set, which to this day I think Venerable Mom and Dad still regret.....]).

Two separate questions from this week's website entries:

1. If you find out any more about the logic behind the cap layer on the roof, I'd be quite interested. Idle speculation makes me think that excluding gravel from the mixture may make the surface more uniform and free from discontinuities (slight depressions where gravel is on the surface, voids where gravel comes out of the mixture during curing, etc.) which could be the starting point for blistering (air would expand at a much higher rate than concrete when heated, and the membrane coating might not adhere as well to the gravel). Exclusion of lime may both create a more residue-free surface for sealing, and slightly alter the surface chemistry of the concrete.

2. I see you got the ubiquitous (in Mexico) black plastic cisterns. (a) Are these filled using simply a float and valve assembly, or is there something like a timer (so filling occurs at night) also involved? (b) Noting that the cisterns are always black, is there some kind of insulation on them, or is it simply the high volume to surface ratio of the water in the cisterns that keeps the water from heating up intolerably during the daytime?

Thanks for any thoughts!

Rolly / Moderator

Dec 8, 2002, 10:50 AM

Post #4 of 14 (2556 views)

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Re: [ET] House Project Update for 7 December 02

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Hola ET,

The water tanks are connected to the city water supply all the time. The in-flow is controlled by a float. The pressure in the city mains is often not sufficient to raise the water to the second story roof level during peak demand periods -- most of the day -- but there is enough pressure at night. We are installing 600 liter (about 160 gallon) tanks which should be a generous amount for a family of four with no landscaping to water.

I too have wondered why the water tanks are black -- cheaper to make I guess. And yes, the "cold" water does get pretty warm which reduces the demand on the water heater in the summer. In fact among my friends in Manzanillo, not a one has a water heater. Several people I know here in Lerdo also do not have heaters. I once made the comment that I like a hot shower even in the summer. My friends looked at me like they thought I was crazy. (One of them regularly calls me Viejo Loco.)

The tank at my house is in the ground to help keep the water cool. We have a pressure pump, so the tank doesn't have to be on the roof. In the case of the new house, we will have pressure pumps, but we had to put every thing on the roof because there just wasn't room on the ground. The patio is awfully small already.

In fact I recently discovered that the patio is 10" more narrow than was planned because an error was made when the foundations and footings were laid out. The living rooms are 10" wider than the plans called for. It never occurred to me that I should run around with a tape measure to double check all the dimensions. Now that it is too late to fix things, I see that I should have done that! We have several errors of that kind. In the end, I will probably be the only one who knows and is bothered by the mistakes.

If I find out the whys of the roof sealing technique, I'll share them.

Rolly Pirate

(This post was edited by Rolly on Dec 8, 2002, 12:36 PM)

Dec 8, 2002, 1:00 PM

Post #5 of 14 (2546 views)

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Re: [Rolly] House Project Update for 7 December 02

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In Reply To

The water tanks are connected to the water supply all the time. The in-flow is controlled by a float. The pressure in the city mains is often not sufficient to raise the water to the second story roof level during peak demand periods -- most of the day -- but there is enough pressure at night.

I take it that backflow prevention into the city's system is mainly handled by the cistern being filled from the top so there's an air gap? I've been told that the lack of water pressure, the pressure cycling in the system, and the lack of backflow prevention in general (not that the US is all that much better in the latter aspect) is why municipal water systems are considered to be contaminated, rather than any problems (post filtration and treatment) at or before the treatment plant.

Are the pressure pumps you're talking about the air pressurized water tanks (they always seem to come from the factory painted sky blue) used in the US, or something different?

In Reply To

I too have wondered why the water tanks are black -- cheaper to make I guess. And yes, the "cold" water does get pretty warm which reduces the demand on the water heater in the summer. In fact among my friends in Manzanillo, not a one has a water heater. Several people I know here in Lerdo also do not have heaters. I once made the comment that I like a hot shower even in the summer.

When I think about it, in line with potentially contaminated water supplies, you'd want your water tank to be opaque to inhibit algal growth, and black is probably a lot easier of a color to achieve in a plastic than the other aesthetically neutral option, white (plus can you imagine what you'd see if you looked inside a white water tank after a few months use?). As for our fetish for hot showers (and in my case, hot baths even in 100 degree weather), mi novia, una Mexicana, has stuck her hand into the shower on more than one ocassion and declined to join in announcing "I'm not a chicken, for god's sake....".

With regards to surveying and dimensional errors, although some others who frequent the Mexconnect forums would probably sum them up as "that's Mexico", this is by no means unique or Mexico related. Last week a friend recounted the latest sins of a large US construction company who in the process of building a large commercial structure he's overseeing, most recently screwed up by mispositioning the bolts embedded into the foundations, requiring that the structural steel be sent back to the factory for redrilling of the base plates (after engineering analysis to verify that this wouldn't substantially weaken the plates). Then to catch up on a severely screwed up crane schedule triggered by the reworking of the steel, the contractor had all the steel set at once, even on foundations that had been poured a scant 48 hours earlier.

And then there's the large government facility who a few years back, ran a multi-million dollar cost overrun when their acre-sized floor slab ended up an inch too high.....

(This post was edited by ET on Dec 8, 2002, 1:04 PM)

Rolly / Moderator

Dec 8, 2002, 5:26 PM

Post #6 of 14 (2534 views)

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Re: [ET] House Project Update for 7 December 02

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Actually the inside of the water tank is white. I haven't checked it out carefully, but it seems to be an inter lining.

The pressure pump is attached to the top of a blue tank that has an internal air bladder. I guess we are talking about the same thing.

In my former life, I was involved in the design and construction of large performing arts buildings - auditoriums, concert halls, TV studios, sports stadiums, etc. I have seen my share of major screw ups. My favorite was the balcony that got built at the wrong slope, so the people in the balcony couldn't see the stage. I was hired to find a solution better than taking it down and starting over. There wasn't one.

There was the addition to an 8-story building on a famous university campus where floors 3 to 8 did not line up when the corridor walls were opened to connect to the new building. And there was the basketball palace build into the side of a hill, where they forgot to install drainage in the service ramp. The first big rain ruined half of the wooden floor.

I guess my little problems are pretty minor. Smile

Rolly

Dec 8, 2002, 10:33 PM

Post #7 of 14 (2514 views)

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Re: [Rolly] House Project Update for 7 December 02

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The pressure pump is attached to the top of a blue tank that has an internal air bladder. I guess we are talking about the same thing.

Thanks again Santa (now about that Porsche.....)!

Those are indeed the tanks that I was thinking of. To my knowledge (and I don't follow these very closely) they come in two flavors, diaphragm pressure tanks and bladder pressure tanks. Although each type has their proponents (and I'm sure that their mothers think that their particular design is the absolutely best there is and handsome, to boot....) to the end user I don't think which type is used is particularly important, at least under normal operating conditions.

I checked the literature for a couple of the polyethylene potable water storage tank manufacturers, and found that they all contained comments along the lines of "black opaque color helps prevent water borne algae growth".

- ET

PS - I didn't see anywhere along the way that the complex was wired for ethernet....

Rolly / Moderator

Dec 9, 2002, 6:58 AM

Post #8 of 14 (2514 views)

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Re: [ET] House Project Update for 7 December 02

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The bedrooms and la sala have TV and phone connections wired back to a central panel for each house. The TV outlets will be wired to a roof-top antenna. Cable TV with high-speed internet runs down the street, so it can be connected in the future. I don't foresee use of the internet any time soon. Internet cafes are so plentiful and cheap that I think it may be another generation before the internet comes into the houses.

Rolly Pirate

Elaine

Dec 9, 2002, 8:02 AM

Post #9 of 14 (2507 views)

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Re: [Rolly] House Project Update for 7 December 02

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Have enjoyed your updates on your construction. A question about the roof, or roofs in general down in Mexico. Are there many, or any, of the metal roofs? I've always said that if I had a house built, or a new roof put on one, that I'd get a metal roof. They last forever and now come in very nice colors that make them as attractive as non-metal roofs.

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When one door closes, another opens. Some people are so busy looking at the door that has closed, they don't see the door that has opened. Keep looking for those open doors.
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Rolly / Moderator

Dec 9, 2002, 8:31 AM

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Re: [Elaine] House Project Update for 7 December 02

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The only metal roofs I have seen are on industrial barn-like buildings. Most homes have pitched (not flat) roofs where sealing is less important. Some are covered with tile, most are not. My own house has a pitched roof with a cap and no sealing -- works fine.

For this project we chose a flat roof because we need a place for clothes lines, and because the patio is small, we need a place for large parties. That is also why the stairs continue up to the roof. Most flat roof homes do not have access to the roof. I think this roof-top patio will get a lot of use. The view is great. We made the parapet one meter high to ensure that drunks don't fall off. I have been to roof parties where there was no parapet; it made me nervous.

Rolly Pirate

Elaine

Dec 9, 2002, 9:03 AM

Post #11 of 14 (2503 views)

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That makes sense. When I lived in Japan, a lot of the homes had flat roofs for the same reasons!

***********************************************************
When one door closes, another opens. Some people are so busy looking at the door that has closed, they don't see the door that has opened. Keep looking for those open doors.
***********************************************************

keith

Dec 9, 2002, 5:10 PM

Post #12 of 14 (2469 views)

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lamina roofs

In the copper canyon, most houses have metal roofs. Here are a couple of examples: http://home.attbi.com/...y52/gettingwater.JPG and http://www.geocities.com/...ueea/newhouseout.jpg. They work pretty well for us, sound nice in the rain. You need to use an entre techo with them because they are hot in summer, cold in winter.

Dec 9, 2002, 11:11 PM

Post #13 of 14 (2432 views)

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Re: [Rolly] House Project Update for 7 December 02

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Although running voice using the same twisted pair cable that you've got ethernet data running through is frowned on in some circles, particularly for 10 Mb/sec baseband applications, it generally works just fine. Although I haven't priced it extensively, it seems that stateside you can now find Category 5 UTP in 1000 foot spool packs for cheaper than the equivalent length of unrated telephone cable. Providing at least one ethernet connection per unit, with each of them running back to a central location would give the future option of sharing a single cable modem or other high-speed internet connection, which might allow for a relatively low-cost entry into the internet.

Elaine

Dec 10, 2002, 8:53 AM

Post #14 of 14 (2421 views)

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Re: [keith] lamina roofs

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Nice pictures. There are a lot of those type metal roofs around this area. I am in the process of selling a farm I inherited from my parents. It was my grandparents' home and the house on it was old when I was a kid. It has had the same metal roof on it since that time and still does not leak. When I lived in the house, I found that insulation had been put in the attic. I put some sheet insulation on top of that. The house was very cool in the summer with the use of only a couple of window air conditioners and warm in the winter, again with only a couple of heaters. There is a lot of new construction being done around here that has the new colored metal roofs and they look very nice.

Oh, BTW, there is nothing better than listening to the rain falling on a metal roof!!!

***********************************************************
When one door closes, another opens. Some people are so busy looking at the door that has closed, they don't see the door that has opened. Keep looking for those open doors.
***********************************************************