Construction Project: Casa "La Esperanza"
Stage Zero - Planning & Preparation
If you are thinking of self-building in Mexico, you should read this blog first. It contains many lessons from which you may learn, and thus avoid mistakes in your own construction.
It is a comprehensive no-punches-pulled account of building a 2 bedroom 2.5 bathroom one-story house on an undeveloped lot in the vicinity of Zamora/Jacona, Michoacán. Construction started in March 2014, and we moved in a year later.
- This page is best viewed with a mouse and full-size screen.
This is the second home construction project I have undertaken in Mexico. The first, named "El Refugio", was built 8 years previously in 2006-7 and has now been sold. It is a beautiful place, and up to a few months ago I felt it would be a sad day if I ever had to leave. But Verónica had been nagging me for less house to clean, and saying I could have everything necessary in a smaller house on just one floor. Remembering what it took to build "El Refugio" and considering its beautiful yet convenient location, I was initially not too enthusiastic. But subsequently I too no longer felt inclined to spend the time necessary to keep the garden in good condition. So as we were increasingly finding "El Refugio" more of a maintenance burden than we could justify, we decided to downsize. We wanted something built to the same standards, but smaller and simpler that offered only what we needed (especially with a much smaller garden).
For the construction of "El Refugio", as I was a newcomer to Mexico and could hardly understand any spoken Spanish, it was necessary to hire an architect. This time, with the experience of having lived here for 8 years, I am the architect; as such I have complete control over the design. Of course, I discussed various aspects with Verónica, and depended very much on the considerable help she rendered. The rationale was to take the things we liked from "El Refugio" but eliminate things we were not using; thus a number of elements in the new house are similar.
We will also supervise construction, purchase materials, and take care of administrative issues. We will thus have much greater involvement in the project and control over its implementation than I had with "El Refugio". Of course, this also means that it will take up a significant amount of our time, and our ability to oversee the work would be limited by only being able to visit the site about twice a week.
2 The Land
The fraccionamiento is named "Quintas La Esperanza", and our street within it is "Renacimiento". Just as the name "El Refugio" (the refuge) seemed appropriate after having escaped the dismal gloom of the UK, the names "Esperanza" (hope) and "Renacimiento" (rebirth) seem appropriate for our new home.
With "El Refugio", the land purchased already had a significant amount of construction, including the boundary wall, an extensive patio, a casita, plus other outbuildings. Here we are starting with a blank sheet. Most significantly, a boundary wall must be constructed, and it is a good idea to complete this early in order to secure the site.
At under $260/m2, the land was remarkably inexpensive considering it has escritura and basic services (electricity, water, and paved roads with street lighting), even though it is a little out of town.
22 Dec 2013
The lot for sale, complete with
The lot is 20m wide x 35m deep (700m2), and immediately adjoins the wall to the right. There is a further 9.7m wide area to the left, which we were initially interested in also purchasing to close the gap. We later learned that this and the adjoining property to the left do not have valid escrituras - this is apparently due to a mistake in marking the boundaries. We nonetheless contacted the owner to see if this could be remedied and we could subsequently purchase the land, but he was not interested in selling. In the end we were not disappointed by this, as the house would fit nicely within the 20m, and I have no use for more garden to maintain.
22 Dec 2013
There is an unoccupied house to the right, with an attractive quinta adjoining the other side.
The lots here have electricity and a water supply from a shared well, although there is as yet no telephone or cable service.
The road is a decent paved one, although it is currently strewn with building materials. There is street lighting, and a curbstone hidden in the grass.
22 Dec 2013
25 Jan 2014
Opposite the house/quinta to the right is the oldest construction in the fraccionamiento - a two-story house that appears to be the only continuously-occupied property here. It is externally almost plain obra negra (although we understand that it is nicely-finished inside, and the owner intends to finish it externally in due course).
The walls on both sides of our lot are about 4m high (that to the right looking from the street is slightly short). We will construct a boundary wall also 4m high.
25 Jan 2014
The boundary wall to the right is an atrocious affair that has been reinforced by a couple of substantial columns, evidently in an effort to prevent its collapse. It has numerous vertical cracks. On excavating for our wall, the reason became clear - over most of its length, its foundation is a mere 50cm deep on notoriously unstable organic soil. Worse, these two reinforcements had no more of a foundation. There is another similar wall in this fraccionamiento built around the same time, and clearly by the same culprit.
26 Feb 2014
The lot is essentially level, but slopes down slightly toward the back - it will have to be carefully leveled to ensure that water will drain to the front gate.
Click here to see a summary of costs involved in land purchase and administration.
3 Administrative Stuff
On 24 January 2014 we signed an agreement with the seller to buy the land. This contract served in lieu of the title in the paperwork involved in transferring the predial, installing the electricity supply, and getting permissions to build. It was especially necessary in my case to have this contract, since as a non-Mexican it is necessary to obtain permission to buy land, and so we would have to wait for this to be processed before the sale could be completed.
To ensure we had a legal boundary, we hired a topographer, whose name was given to us by the construction office in Jacona. At the same time, we needed permission to build, which the topographer offered to handle. I thought it would be better to get permission for the entire construction at the same time, but the topographer said it would be better to do it in two stages - firstly that for the boundary wall, and secondly that for the house. This is since the former requires only basic basic structural details and can be completed fairly quickly; however permission for the house requires a full set of plans and structural calculations that must be completed and signed off by a structural engineer.
The topographer was entrusted to obtain permission to build the boundary wall, but apparently had to return twice to the construction office in Jacona due to errors he made. Although the permission was not complete, we were nonetheless given a verbal green light to begin construction of the wall. The final document still had a basic error in that the height of the wall was given as 2.5m, not the 4m we wanted and which was the height of the walls of the neighbors either side. And the boundary he marked was clearly incorrect as the frontage measured 20.20m not 20m. Since it seems he simply measured it from the property to the right, we adjusted it accordingly in the hope that this boundary is correct.
The topographer also offered to do the full set of plans, plus the structural calculation that is required to obtain permission to build the house (even though he was a topographical engineer, not a structural one). But it had become clear to us that he was an incompetent alcoholic; instead the necessary work relating to the house plans (including obtaining permission to build the house) was done by the structural engineer who checked and signed off the plans for "El Refugio".
We also had to consider Social Security payments (IMSS). Because we were to build a one-story house, the risk is lower than it was for "El Refugio", and some considered we need not bother. However, anecdotal evidence suggests that failing to pay IMSS contributions is not a good idea...
4 House Design
The design of "El Refugio" was primarily that of the architect - although I specified what I wanted, and subsequently commented on and insisted on some changes in the provisional plans produced, it is fair to say that he was in the driving seat. This was especially the case since being a newcomer to Mexico at that time, I had little knowledge of the options available. But this time, having lived here for over 8 years, I was in a position to originate the plans.
4.1 More Efficient Use of Space
The new house is on one level with 2 bedrooms and 2.5 bathrooms. The design is much more compact than that of "El Refugio", and is intended to be generally cozier with less open space. I put some effort into keeping things down to just what was needed, hopefully avoiding making spaces too small for furniture and people to fit in (in any case we will have to ditch some of the furniture of "El Refugio"). In fact with a gross area (including walls) of 252m2 (2710 square feet) with the covered porch and terrace of 22m2, the house is not really small. There is also a covered outdoor entertainment area with kitchenette, and an outbuilding.
The house at "El Refugio" is open on all sides, and consideration was therefore given to providing pleasing esthetics to each of the four elevations. In contrast, the new house is to fit closely within the 20m width of the boundary wall - as such, only the front elevation is important esthetically. One could save money by using the boundary walls as three of the house walls, thus only requiring a separate front wall. But we considered it better to isolate the house completely from the boundary wall, and have a path in between. The height of the boundary wall is 4m, and that of the house 4.3m, with a gap of 1.2m in between.
4.2 Multiple Roof Sections
To the front, roofs are sloping with bóveda ceilings; since the house faces directly into the strongest sun, attention has been paid to providing good shading here. The front of the house is therefore very sheltered, most of it being a covered terrace, with an overhanging roof over the living room to the left.
Also, I aimed to provide not only a pleasing front elevation externally, but varied and appropriate ceilings inside. To this end, the front has four roof sections, which from left to right are:
- A double-sloped roof over the large living room; the ceiling height ranges from 3.2m (10'6") to 3.95m (13'0").
- A single-sloped roof over the kitchen and terrace; the kitchen ceiling height rises from 2.32m (7'7") by the terrace to 3.0m (9'10").
- A double-sloped roof over the entrance hall and porch, with ceiling heights as per the living room (but more steeply inclined).
- A single-sloped roof over the sitting room, half bathroom, and terrace; the ceiling height of the sitting room ranges from 2.32m (7'7") to 3.85m (12'8").
To the rear and center, roofs are flat losa 30cm thick with skylights instead of windows. In these areas, the ceiling height is 2.75m (9'0").
4.3 Three Zones
There is a division into three zones, from open (front) to private (back):
- Open to all visitors (entrance hall, half bathroom, outdoor areas)
- Restricted (living room, sitting room, kitchen, pantry, dining area, bar)
- Private (bedrooms, main bathrooms, study, laundry room, stairs to roof)
- The Open zone
- includes the covered outdoor entertainment area with kitchen and built-in tables and seating similar to that of "El Refugio", and the terrace. For parties, people have access to the half bathroom and entrance hall via the terrace and porch; the front door will then be left open, and the door behind can be locked as required. This avoids the need for an additional half bathroom for parties, as is present in "El Refugio". The path from the portón to the front door by the entertainment area is completely covered, so that one can enter in the rain without getting wet. There is a separate path down the center of the garden direct to the porch. There is also an outbuilding for storing tools, etc.
- The Restricted zone
- has sloping bóveda ceilings and normal windows, except for the dining area/bar which has a flat roof with skylights. There is a large living room and smaller sitting room, both similar to those in "El Refugio". The kitchen area is much more compact, but with a separate walk-in pantry. The dining area has a built-in dining table similar to that in "El Refugio", with a separate built-in bar counter.
- The Private zone
- is accessed from the restricted zone via a short passageway with at least one solid door (a second door could be fitted if required). There are no external windows - instead light is provided by skylights in the 30cm thick losa. Each skylight comprises two 20cm square blocks of thick glass separated by a large space. The corridor is lit by 16 such skylights, and provides light through internal windows to the two bedrooms and study. The bathrooms and study have their own skylights, giving a good level of natural light here; the bedrooms have no skylights, making them (appropriately) rather darker. Apart from the exit to the restricted zone, there is a door at the end of the corridor leading to the laundry room; by the side of this is a room under the stairs where the circuit breaker box is located. At the end of the corridor is a robust double-paned sliding door leading to stairs to the roof; these are inside the 4.3m wall of the house, which in turn is inside the 4m boundary wall. The shared bathroom is rather larger than that of "El Refugio", also having a bathtub with hydromassage ("Jacuzzi"), but with a separate shower cubicle.
4.4 Other Criteria
Both external doors (by the entrance porch and by the laundry room) are to be of heavy-duty aluminum and double-paned with decorative reinforcement between the panes (the laundry room door is actually within the house wall). The side door and all external windows have sliding mosquito nets; it should be reasonable to leave them open most of the time. This, together with the provision of ceiling fans should give good ventilation, despite the seclusion and soundproofing of the private zone making it somewhat ventilation-challenged.
As the water supply is discontinuous, there will be an aljibe with a capacity of 12,000L under the outside dining area; a submersible pump in this will supply water to the 750L tinaco on the roof. We also plan to have a pressure system, solar water heater, and perhaps a water softener (if the water proves to be hard). We will use PEX rather than copper for the water pipes; this will give better insulation for hot water and also avoid noises from knocking in the pipes when the pressure system pump cuts out. We will build a 4-chamber septic tank; the 4th chamber will hold agua gris suitable for irrigation.
5 House Plans
I aimed to complete the plans myself as far as possible, having the benefit of a significant amount of experience in using AutoCAD Architecture. I had some firm plans sketched out by 21 February 2014, based on the above design principles. The basic design has changed remarkably little since then, but quite a lot of refinement was needed to produce plans to build the house. I put some effort in to making them as simple as possible, since complex plans are likely to lead to more mistakes in construction. I initially concentrated on the house, since the phase 1 items (boundary wall, septic tank and storage building) should be relatively straightforward; the only significant design work here is that for the fachada.
The plans that I submitted to the engineer were almost complete except for a few technical details, mainly in the foundation. These were then completed and signed off by the engineer in order to get permission to build (this was done around 23 May 2014). The engineer provided a completed foundation plan and a new roof plan, but the foundation plan was subsequently modified and the roof plan found to be unusable. So in the end, the plans we used included relatively little from the engineer.
07 Mar 2014
5.1 Facade (initial plan)
My idea was a "fachada sin acabado" using only structural material in a decorative manner, avoiding having to cover it in any way, thus saving money and possible future maintenance. The wall is south-facing, and is thus exposed to the sun and rain, so I wanted the most durable possible finish; especially to avoid paint, which was clearly in poor condition in the recently-built neighboring properties. The biggest issues were in covering the ugly castillos and dalas. The castillos would be surrounded with columns of yellow tabicón (concrete block); the dalas would be enclosed in a "sandwich" of red adoquín. Diamond patterns in yellow tabicón would lend some interest to otherwise plain surfaces in between.
The portón is 3m high to allow vehicles such as trucks and excavators to pass underneath. This was particularly important since the house was to be built after completion of the boundary wall. Originally I was thinking of having only a single doorway, with a small pedestrian door inset in one of the four leaves. However, it seemed better to provide a separate pedestrian entrance to the side. In searching for a design for the steel doors, I used Google Earth Street View; in Ajijic (by Lake Chapala) I found a design that was attractive, and also appeared to be inherently strong and easy to make.
The plan was based on the (overwide) 4m spacing of castillos as introduced by our phase 1 "maestro", but before various other problems arose. It was made out with an exact number of blocks assuming a normal mortar thickness of 1cm, although the design is inherently tolerant of inaccuracies in construction. Nonetheless, this plan was wrecked by the "maestro" in charge of the first phase of construction; through grossly over-thick mortar layers, by incorrectly-placed castillos, and every other mistake that could possibly be made in this easy-to-build design - see the next page.
5.2 Complete Plan Set
These are as used by the maestro to build the house. Each of the four plans is printed individually on 60cm x 90cm paper to give a scale of 1:100, or 1cm = 1m (except where otherwise noted). This enables easy measurements to be made with a ruler, where they are not explicitly given.
The plans are divided into four sheets as follows:
The information on the first three sheets is required to obtain permission to build; the fourth is for "internal" use only. Only the second and third plans were modified by the structural engineer, but we used the original roof plan.
A set of structural calculations of loads and stresses etc. is also required for permission to build - this would normally have to be done by the engineer.
5.3 Sheet 1: Architectural Plan
Several cross-sections were needed to illustrate properly the various roof sections. Color coding is used to indicate relative levels (for example the floor of the house is 15cm higher than the main garden area). Apart from this, there must be drainage to the front; for example the path at the back of the house is about 20cm higher than the parking area.
The floor plan includes the furniture we intend to keep; not all the furniture from "El Refugio" will fit in the smaller house.
5.4 Sheet 2: Foundation Plan
I provided an incomplete version of this plan, which was completed and modified by the engineer; this was used as a basis. The engineer felt that I used thicker castillos than necessary; however subsequently our maestro Rubén found those of the engineer to be too thin, so we agreed changes to the plan. This also included simplification, since the plan of the engineer was clearly over-elaborate - for example in specifying numerous different types of castillo that were essentially the same thing.
The plan uses zapatas corridas throughout in a reinforced concrete foundation. Note that in some cases cadenas are used (contratrabes without zapatas); in these cases there are no walls to support, and they are there to complete the horizontal loading chain (important in earthquakes).
The boundary wall and storage room were built before this plan was available, and thus do not conform to it (these items are part of the first phase of construction).
5.5 Sheet 3: Roof Plan
The roof plan provided by the engineer was completely unusable. Although it should have been clear from the plans I submitted that I wanted only the front areas to be bóveda with standard flat losa to the rear, the plans were drawn with beams and bóveda throughout. Moreover, the beams were ridiculously oversized (using "El Refugio" for comparison, which itself is hardly a lightweight construction). The design in the large living room was to have a system of three primary beams which in turn would support secondary beams which in turn would support the bóveda. The primary beams would each weigh over half a tonne, including one at the apex; this would transfer considerable load to the walls (especially in an earthquake). In another place that corresponds exactly to the inclined roofs in "El Refugio" using straight beams, there was a system of cross-beams. There were also clear errors that led us to have no confidence in this plan.
So my original plan was used. The double-sloped roofs use a much more efficient A-frame approach, whereby the inclined beams are the primaries that support a secondary at the apex. The flat roofs would be 30cm thick; 20cm of reinforced concrete, 9cm of firme with baldosa on top. This will give plenty of thermal mass to stabilize night/day temperatures, as well as considerable soundproofing.
The plan also specifies roofs in outdoor areas, including from the entrance to the door, so that one will not get wet entering the house in the rain. The house and marquesinas will have clay tiles; roofing over the path and entertainment area will be of decorative steel laminate.
5.6 Sheet 4: Installations and Finishing
This includes the electrical plan (also giving gas appliances), sanitation plan (plumbing in the foundation), design of the septic tank and registros, together with details of finishing including the fachada and carpentry (kitchen units and general). The electrical plan is a user specification only; it is not a wiring plan, as our plumber/electrician will determine this once the relevant masonry is in place (the same applies to the plumbing).
There is a circuit box in the storage room with four circuits for outside areas, with the main circuit box with 24 circuits being located in the house under the stairs. We plan to have a whole house voltage regulator in case of voltage spikes. The plumbing will be properly vented as we have had in "El Refugio".
6 Implementation of House Plans
Click here to see a summary of construction costs.
As mentioned, we first had permission to build the boundary wall; permission to build the house would take a while longer. As a result, the construction would proceed in two phases:
- the boundary wall with fachada, plus a septic tank by the front left corner with a storage room over.
- the house, plus an aljibe, entertainment area, paths, and general finishing.
These two phases are not to be confused with the six construction stages as given in the following pages; the first phase comprises stage 1 only, and the second phase the remainder.
The first phase was started before the main house plans were available. However, I had already completed the (initial) design of the fachada, this being the only part of the phase 1 work that was not basic albañilería.
With the construction of "El Refugio", I lived on the site in the casita while the house was being built; I was therefore able to inspect the work (and take photos) on a daily basis. In addition, I had an architect who should also have undertaken this role. With the new construction, we will not be able to visit the site more than about twice a week; once on Saturday (to pay the guys) with hopefully another visit in the middle of the week. As a result, there is a risk that structural defects may go undetected, or not be caught early enough for them to be easily remedied.
The main players in the project were:
- Myself - project designer, chief inspector, disbursement executor, general supremo
- Verónica - project secretary, chief chatterbox, procurement manager, general administrator
- X - the utterly inept and negligent "maestro" of phase 1 (whom we terminated)
- Rubén - the highly capable and experienced maestro of phase 2
- Jaime - our highly resourceful and experienced plumber/electrician (both phases)
Both Rubén and Jaime did the construction of "El Refugio"; Jaime had also done a number of jobs there since, and was well known to us as someone decent and capable. However at the start of the project, Rubén was long since gone, and we did not know his whereabouts or have another clear option for a maestro. Two people were known immediately:
- X - the husband of a long-standing friend of Verónica
- Y - another acquaintance who was well known to us from work at "El Refugio"
Y was known to be decent and fine for obra negra, but not so good at acabados; we also doubted he could work from complex house plans. X persuaded Verónica that he had some special technique for laying rock in foundations (I was not too convinced), and that he was generally more capable, having built entire houses (I wondered what kind); Y at that time already had work. X was thus appointed maestro, with Y joining the team a little later.
Although I was concerned that X was something of an unknown quantity, the work in phase 1 is fairly basic, and we could see how things went before deciding if we needed other people for the house. Notwithstanding the assertions of X that he could do everything, I hired Jaime for the plumbing and electrical installations. However, we initially tended to leave the construction very much in the hands of X, as I did think he would at least be able to manage satisfactorily the simple work of phase 1. I was wrong...