ONLINE BRUSSELS HERITAGE - ONE-DAY SEMINAR - 11/12/2014

An assessment must be made as to how this new Level of performance relates to the original environment, which is of course lower in performance. Installing high-performance glass in a non-insulated wall must be done with care to ensure that a healthy interior climate is maintained. It is also usually necessary to insulate the walls (at least partially) or to install a well-functioning ventilation system. In many cases, adapting the level of insulation can provide a solution.

INSULATION OF THE ROOF

As long as an insulation mat is placed between the rafters - i.e. within the material contours -there is usually no problem with the roof. However, the standard for each building element requires more; extra insulation on the exterior is often a solution, but it is a very awkward measure in larger wholes, such as the Le Logis-Floréal garden cities (fig. 11). In that case, raising the roof (a necessary step to accommodate the extra exterior insulation) must be carried out in consultation with the neighbours so that the entire row can be renovated, thus avoiding unevenness and awkward-looking connections in the roof surfaces. Even then, cohesion with the façade is not easily solved. The austerity and simplicity of these houses means that few new elements and details suit them.

It becomes even more difficult with a roof with dormer windows (fig. 12 and 13); the architectural relationships become distorted and the ornaments lose their elegance due to a somewhat inflated effect.

Self-supporting systems are often opted for in order to lessen the

Fig. 11, 12 and 13

Insulation of the roof is indisputably an energy efficient solution. Nevertheless, the problems of installing it around a dormer or on a raised roof over terraced houses must be thoroughly assessed before installation takes place.

20 | Architectural heritage and energy performance