Foundations for a glulam house near Moscow

The wall is light and stiff; the ground around Moscow is heterogeneous and often wet. That combination, not the fashion of the year, decides the foundation.

Why the light wall is the problem

A glulam wall weighs a fraction of a brick one and it is rigid along its length. Frost heave therefore does not get pushed back by the building’s own weight, and uneven lift shows up as a door that stops closing rather than a crack that relieves the stress. The answer is either to take the load below the frost line or to build a slab stiff enough to move as one body.

The three common answers

• Insulated slab. Forgiving on heaving clays and the usual choice when there is underfloor heating. The most expensive to start, the cheapest to live with.
• Screw or bored piles with a grillage. Fast, works on a slope, needs a real survey — pile length comes from the soil, not from a price list.
• Shallow strip. Fine on sand with low water, poor on clay without insulation of the blind area; the option most often chosen for the wrong reason, which is habit.

What to insist on

A geotechnical survey with at least two boreholes, the water table recorded by season, and a drawing with the foundation’s own loads. Then a levelling check of the finished foundation before the first beam is laid: a kit cut to the millimetre on a CNC line will not forgive twenty of error in the base.