asiento here means subsidence or settlement. Not sure adding value would be entirely necessary.

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Note added at 1 hr (2012-05-08 21:55:04 GMT)
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On second thoughts, settlement would be better than subsidence as this is a new build.

http://www.policyexpert.co.uk/blog/cracking-up-do-you-know-y...

What is the difference between “settlement” and “subsidence”?

Settlement usually occurs in new or relatively new buildings. They are very heavy and cause the ground to compact, but this normally stops after a short while. Additionally, most buildings are constructed in a variety of materials, all of which need to settle down and have different shrinkage rates. It is not unusual for a builder’s contract to require them to come back in six months to make good those settlement cracks that have appeared, for instance, between the walls and ceilings. In older buildings of a more flexible construction, cracks can appear in the summer that close up in the winter when the materials absorb moisture. These are known as “summer cracks” and are usually non-serious.
http://www.proinspect.co.uk/extended-advice/subsidence/

SETTLEMENT - is caused by the weight of a new building/structure or part of it. Buildings are heavy things and, as their weight is taken up by the ground, a little movement caused by this adjustment sometimes occurs as the ground consolidates under the new load- this is settlement. It usually occurs early in the life of a building and rarely recurs, although, there are exceptions, for example, in soft clay soils. Settlement rarely causes problems, although differential settlement (differing degrees of settlement between connected parts of the same structure) can cause damage.

SUBSIDENCE - results from external factors which cause the disruption, displacement, contraction or distortion of the ground under or around a building. Some of the more common causes include:
TREES - trees extract moisture from the ground which then contracts, particularly in shrinkable clay soils, causing buildings above to move (subside).
DRAINS - leaking drains can wash away or erode the adjacent ground which then partially collapses reducing the lateral (sideways) strength of the ground. The support provided by this ground will then be reduced causing any building above to move (subside).
MINING - mining removes part of the ground below the surface (leaving shafts and tunnels) and which reduces its ability to support the ground above. If these shafts or tunnels collapse, the ground above drops as well, causing damage to any buildings.
BIODEGRADATION - domestic refuse disposed of in the ground usually breaks down and consolidates at a steady rate. However, the apparent soundness of the ground can be misjudged and further decay/compaction occur resulting in movement (subsidence) of the ground and any buildings above.
COLLAPSE - the collapse of a sewer, for example, can cause the ground/buildings above to drop (subside).
http://www.viewingessential.com/pp_subsidence.php

http://www.proz.com/kudoz/spanish_to_english/construction_ci...