Diest is an old city in Belgium with for example a church built in 1253. As a consequence, old buildings with some history are renovated instead of demolished to keep the typical warm culture of Diest alive.

In the Koning Albertstraat, an old building (1880) was bought for renovation by Pieter Wellens. The main building is kept while the extension is completely renovated from scratch.

For the floor insulation of the extension, GLAPOR RDS has been chosen due to its sustainability at a good price.

It was decided to insulate also the foundations of the old part, constructed with bricks and a lime mortar. Newly developed high density GLAPOR cellular glass will be installed with a Unilit TD 1320 mortar between foundation and wall.

This high density cellular glass (160 kg/m³, about 300€/m³) is installed without (bitumen) coating and for that reason a lime mortar is needed. Compressive strength of cellular glass and mortar exceeds largely 2000 kPa. All the cellular glass, used in this project is manufactured for 100% from waste glass, unsuited for the production of new bottles or windows.

Although GLAPOR made a large effort to deliver at an attractive price, the major challenge is for Pieter Wellens, who decided to renovate in the city instead of building from scratch outside the city. Renovating old buildings is ecology at the best.

Above we see how the floor insulation of the extension has been done. Special GLAPOR boards (RDS system) are enclosing the gravel and will serve later as form work for the concrete slab on top of the foamed glass gravel. Due to the lack of space in the city, the gravel is unloaded from big bags.

On top of the GLAPOR structure with the concrete slab, a passive housing construction of ISOVARIANT will be build. ISOVARIANT is based on EPS and contains the concrete wall. It serves as form work for the concrete and as thermal insulation. The load of the walls and rest of the building  is distributed over the vibrated GLAPOR gravel system by the concrete slab.

GLAPOR system sustaining the concrete slab

ISOVARIANT system on the thermally insulated concrete slab