The challenge was enormous: the flats were to be integrated into the church
without affecting the character of the building from 1900. For the partition walls
inside, between mighty columns and church windows, the client and architect chose
ready-to-use elements made of Silka sand-lime bricks, 300 millimetres thick. The
building material consists of lime, sand and water. Some of the walls in the
monumental building are now up to seven metres high.

Just a few years ago, no one would have expected this. For the Heilig Hartkerk was
taken out of use in 1985. Occupants moved in, illegal parties were organised.. In
2000, permission was even given to bulldoze the Christian building. But committed
citizens ensured that the church, presbytery and monastery were declared a
national monument after all. Now twenty flats ranging in size from 50 to 232 square
metres fit seamlessly into the ambitious conversion.

Digital teamwork

The basis for this unique project is digital construction planning, which Xella also
uses. With the help of BIM, Building Information Modelling, builders, architects and
craftsmen can exchange all information digitally right from the planning stage of the
project. This means that everyone involved knows at all times what the other trades
are currently planning, changing or carrying out. This reduces construction time,
construction costs and makes it easier to realise even unusual solutions such as
the conversion of a church.

Engineer Dennis van der Bruggen worked out the project for the builders in BIM.
"Based on the architect's and structural engineer's drawings, I calculated and drew
the wall profiles. Everything was worked out so that the Silka elements were
delivered ready for use. The fitters can put it together on site like Lego."

Building in arches

For Van der Bruggen, finding the right solution to build in an existing building was a
particular challenge. After all, he had to contend with the existing, unusual heights.
"For example, the high and low vaults that also run in an arch. That's a real task,
especially for the execution: how do you bring all the material in properly? You don't
want to plan too closely to the existing building, because all the materials are still
'working' after completion."

Van der Bruggen has therefore worked out the walls in whole elements as far as
possible. "Fitting pieces are only used in exceptional cases. This makes it
particularly easy to assemble, i.e. glue, the elements together."

Due to their compressive strength, walls made of Silka sand-lime bricks are highly
loadable even with low wall thicknesses. They are non-combustible and absolutely
frost and weather resistant. Thanks to their high density, Silka sand-lime bricks are
also particularly sound-absorbent.

Obviously, the colleagues from Xella Netherlands are doing a good job. They were
also chosen for the renovation of another national monument. In Heerlen, the
Christus Koning Church was transformed into a fire-proof archive.