A new roof covering, insulation or solar panels? We recheck the roof structure for the planned build-up and the added loads, and tell you whether strengthening is needed.
Free quote, first reply within 24 hours.
Replacing the covering, insulating or installing panels changes what the roof structure carries. We check the existing structure with the future build-up: covering, insulation, rails, panels and any ballast, under Belgian snow and wind loads.
Timber, steel or a concrete slab: we record the sizes, spans, bearings and condition of the members. Visible deflection or decayed timber changes the assumptions.
Switching from slates to tiles can double the weight of the roof covering. On-roof panels add around 15 kg per m², rails and hooks included (about 10 kg for the panels alone), and roughly 25 to 50 kg per m² with a ballasted system on a flat roof, concentrated along the support lines.
In Belgium, the snow load is 0.5 kN/m² on the ground below 100 m of altitude, and snow can drift against a higher wall. Wind lifts the panels and pushes on the building: the capacity of the structure is our responsibility, the fixings are the installer’s.
If the capacity is not sufficient, we design strengthening or another layout. The chosen support points must match the assumptions in the file.
Avoiding holes in the roof membrane means ballasting the supports. That weight is concentrated in blocks or lines on the joists: the structure and the layout are checked together, not just the available area.
You do not need a complete file to contact us. These items help us understand your project and give you an accurate quote.
Panels on an existing roof and a like-for-like replacement of the covering are, in principle, exempt from a permit in all three Regions, subject to conditions on visibility, projection or pitch that vary by Region. A dormer, a roof terrace or a change of volume requires a permit, normally with an architect. An exemption from a permit is not an exemption from calculation.
The price depends on the type of roof, the information available and the mounting system: we send you a quote after a first conversation, plus 21% VAT. A precise panel layout allows a tight quote.
See the price guideThe check covers the structure. Waterproofing, the electrical installation and solar output are the responsibility of the roofer and the installer, with whom we coordinate the interfaces.
Direct contact with the engineer handling your project, at every step, in English.
Request a quoteYou describe your project. Together we define the scope of the design and the quote.
We review your documents and, if needed, arrange a site visit.
We design the solution and explain what it means for your project.
You receive the agreed documents, in English if you prefer, with the explanations you need for the next steps.
If the weight changes, yes. Replacing slates with tiles can double the permanent load; so can adding thick insulation. Send us both build-ups and we will tell you which checks are useful.
No. The whole system counts: rails, supports, ballast and their layout. A ballasted system weighs several times as much as the panels alone and loads specific points.
No. Many roof structures can take on-roof panels without modification. The calculation confirms it or identifies the members to strengthen; the appearance of a roof structure says nothing about its reserve capacity.
A roof made accessible moves from a maintenance load to a much higher imposed load, with a balustrade to anchor. It is a full structural check, and in Brussels a permit with an architect.
Tell us before installation. Another model, other ballast or a different layout can change the assumptions and require an update of the check.
What your house can carry, and the structure of the new level.
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Cracks, movement, doubts before buying: a clear, signed structural engineer’s report.
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Foundations, new structure and connection to the house, for an extension without surprises.
Learn moreA few words, and your plans if you have them.
We will help you define the right scope.