House extension in Woluwe-Saint-Lambert

Integration of the extension into the existing building and surroundings

Foundations and connection to the main building

A well-built extension starts with foundations sized according to the nature of the soil. In Woluwe-Saint-Lambert, some areas have clay soil at depth, particularly sensitive to seasonal humidity variations. The foundations of the extension must be calculated accordingly to avoid differential settling between the main building and the extension. The structural connection between the two building bodies is a delicate step that we handle with our stability engineers.

Thermal performance and thermal bridges

A poorly insulated extension consumes more than the rest of the house and deteriorates the overall energy performance certificate (EPC) score of the property. Thermal bridges form at the junctions between the extension and the existing building, at the slabs and window frames. We size the insulation of each wall according to the requirements of the Brussels Region (EPC), with particular attention to the interfaces between volumes. A well-designed extension can achieve a performance level equivalent to a new low-energy construction.

Networks: electricity, heating, and plumbing of the extension

Connecting the technical networks of the extension to the main building requires a prior analysis of their capacity. The existing electrical panel may not have sufficient capacity to supply a new living space. The current boiler may not be sized to heat an additional area. We carry out this diagnosis before estimating costs to identify necessary upgrades, and we integrate these costs from the initial estimate, not after signing.

Completion times and daily life during construction

An extension project in Woluwe-Saint-Lambert lasts on average 8 to 16 weeks depending on the area and construction technique. Timber framing is the fastest technique, and the structure can be weather-tight in 2 to 3 days. Traditional masonry takes longer but is often better accepted by urban planning commissions in dense residential neighborhoods. In both cases, the main construction represents about half of the total duration, with the rest dedicated to finishing trades and details.

Realize your extension project in Woluwe-Saint-Lambert

Expanding without moving means staying in your neighborhood, keeping your bearings, and increasing the value of an already well-located property. The first step is a free visit: we analyze together the potential of your house, check what urban planning allows, and build the project that suits you.