He was also aware of connections between Henriksson and Ahti. Owing to the eco-
nomic depression, the contracts were hotly competed, as evident in the case of the
concrete frame contract for Paimio Sanatorium.
The frame solution for A and C wings altered between the competition stage, January
1929, and the master drawing stage, April 1930, to a significant degree, while B wing
changed only in its roof terrace. In January 1929, A wing had two load-bearing external
wall alignments and one row of columns within the frame. In April 1930, only one of
the external walls was load-bearing. In January 1929, C wing similarly had load-bearing
external walls and a load-bearing row of columns inside. By Christmas 1929, it had
acquired two load-bearing rows of columns within the frame and non-load-bearing
external walls. B wing in turn kept its load-bearing external wall alignments throughout
its development. As a result, each of the three main wings had a different frame solution.
In April 1930, when the principles for the load-bearing structures had been resolved,
the design was submitted to the State Medical Board for approval. The work specifica-
tion at this stage included such detailed instructions on the execution of the concrete
construction that the author of these specifications must have had both theoretical and
practical competence on the subject. The architectural drawings and building specifica-
tion of this specific stage were given priority in the concrete frame contracting process.
It would appear that Aalto had invited Henriksson to join his team before the design
collaboration formally began in May 1930. From the perspective of power relations, it
is interesting to note that the strength calculation engineer signed the contract specifi-
cally with Aalto, not the Building Board of the Tuberculosis Sanatorium of Southwest
Finland. The Building Board did not want the contractor to conduct the structural
calculations although this was common practice at that time. If the contractor had been
allowed to use their own strength calculation engineer, the collaboration between Aalto
and Henriksson, which had lasted several projects, would have probably ended and
perhaps a similar fruitful relationship would not have formed with any other engineer.
The column, beam and slab frame in Paimio Sanatorium was innovative considering
the type of building it was applied to and the period. Some of the structures were more
conventional, such as the intermediate floors supported on external walls^731 while others
were more ground-breaking, such as the cantilevered interim floors of the sundeck wing
and the large freeform entrance canopy, which acquired its final shape between July and
August 1930 as a collaboration between the architect and the structural engineer.^732
Aalto also managed to salvage the suspended interim floor slab in the B wing dining
hall, regardless of the medical experts having unanimously rejected the structure in their
statements on the competition entries. Aalto drew diagrams to translate the doctors’
interests, illustrating how the structure would allow sunlight penetrate to the furthest
731 In the interwar period, interim floor slabs were almost without exception built from reinforced concrete. The most
typical structure was the slab-and-beam construction, on top of which rested a separate floor structure. The
structural thickness was typically 40–45 centimetres. Neuvonen et al. 2002, pp. 100–101.
732 See drawings Emil Henriksson No. 5. PSA dated July 1930; and drawings Nos. 50-306 and 50-307, dated August
25, 1930, and signed by “H.H.”