What you cannot see is what holds it up
A badly executed foundation gives no warning. It does not craze within a week or leak in the rainy season. It shows up years later as diagonal cracks in walls, doors that stop closing or floors that lose level, and by then correcting it means working underneath everything built on top.
That is why it is worth stopping before the pour. The four decisions that define a foundation — ground, reinforcement, cover and concrete — are taken over a couple of days and condition the following decades.
The ground rules
Before the material comes the soil. Bearing capacity, the presence of expansive clays, the water table and the depth of firm strata determine the foundation type and the geometry of the elements. That information is not guessed on site: it comes from a study.
In civil works, lime is used precisely to stabilise subgrades and bases, improving the bearing capacity of clay soils. It is a known and accessible solution, but it only makes sense once you know what soil you have.
The reinforcement: diameter, lap and tying
Reinforcing steel supplies the tensile strength concrete lacks. The structural design defines diameter, quantity, spacing and lap length. None of those four figures is negotiable on site for purchasing convenience.
The lap is where the worst savings are made: it guarantees continuity of reinforcement, and trimming it compromises the capacity of the whole element for a few kilos of steel. Tying with annealed wire is no minor detail either: a badly tied cage shifts during the pour and ends up out of position.
Cover protects the steel
Between the bar and the outer face of the element there must be the cover the project specifies for the exposure. That thickness of concrete is the only thing protecting the steel from corrosion, and its absence is not noticed until rust stains appear.
To respect it, spacers are used and the cage is tied properly so it does not shift when the concrete comes in. If the cage sits against the formwork, the bar corrodes even in good-quality concrete. In coastal areas like Rosarito or Ensenada, that care matters even more.
The concrete and the pour
Strength is set by the design. What is decided on site is how it arrives and how it is placed: slump suited to the cage, continuous flow to avoid cold joints, correct vibration to eliminate voids and immediate curing.
On a foundation of any volume, ready-mix with pumping is worth it: it keeps continuity, respects the design slump and avoids the barrowing that forces watering down the mix. And if the pour falls in the hot season, the usual three rules apply: schedule early, shade and shield from wind, and place and finish in the shortest possible time.
