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A roof without an overhang: what happens at the eaves?

A roof without eaves means the slope ends essentially at the wall line rather than beyond it. This arrangement still requires well-planned drainage and ventilation right at the façade. Gutters, flashings and air inlets must be resolved at the design stage, as must service access. Metal roof tiles can be suitable provided they match the pitch and details. What matters most is water runoff and continuous insulation where the roof meets the wall. Simply shortening the rafters is not enough, because runoff conditions and wall protection change.

By |2026-11-14T23:56:28+01:002026-08-16|Knowledge base|Comments Off on A roof without an overhang: what happens at the eaves?
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How do you calculate the cost of a photovoltaic roof over its entire service life?

The purchase price marks the start of the investment, but not its full cost. A photovoltaic roof will require servicing, and some equipment may need repair or replacement. At the same time, it serves as the roof covering and generates energy. A reliable comparison should cover both functions over the same period. There is no need to build a complicated model, but it is worth explicitly recording the costs, benefits and uncertain assumptions. Choose a common horizon for all the variants under consideration. Do not compare one solution over a short period and another over the entire expected life of the building. A distinction must also be made between the warranty period and the durability of each component. The covering, the active elements and the electronics do not have to share an identical service history.

By |2026-11-15T19:00:00+01:002026-07-23|Knowledge base|Comments Off on How do you calculate the cost of a photovoltaic roof over its entire service life?
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Where does a roof slope need a ventilation outlet?

A roof-slope ventilation element is needed when the design or the covering instructions require supported airflow within the roof layers, especially on a long slope or where a window or chimney interrupts the channel. It does not replace a clear inlet and outlet. Before choosing, check that the gap has an inlet, an unobstructed route and an outlet, and that the element matches the covering profile and roof pitch. Its location follows the design and instructions, not a general rule.

By |2026-11-14T23:57:14+01:002026-07-01|Knowledge base|Comments Off on Where does a roof slope need a ventilation outlet?
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In what order should the panels be installed so that the walls and roof form a tight envelope?

A tight envelope is created by following the correct sequence of work on the walls, roof and openings. Simply screwing the panels to the steel is only part of the job. The base must be prepared beforehand, the sealing layers joined and access left to areas that will later be covered by flashings. This allows subsequent teams to work without redoing completed sections. On the envelope drawing, mark out the wall sections, the laying direction and the working zones. Indicate which elements must be installed before the panels: base rails, tapes, parts of the flashings and the substructures for openings. Adapt the sequence to the chosen system. There is no single rule that in every building you always start with the same building element.

By |2026-11-14T12:52:55+01:002026-06-26|Knowledge base|Comments Off on In what order should the panels be installed so that the walls and roof form a tight envelope?
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Choosing a roofer and agreeing the scope of work

Choose a roofer based on projects similar in material and complexity, not price alone. Check whether the team knows the installation instructions for the selected system and can point to the document they use. Before work starts, agree materials, details, dates and the handover method, as well as how additional work will be settled. With metal roof tiles and trapezoidal sheets, flashings, fixings and ventilation are particularly important. Look at details in photos and, with the owner's consent, a finished roof – a distant overall view does not show the quality of edges and finishes.

By |2026-11-15T03:57:41+01:002026-06-10|Knowledge base|Comments Off on Choosing a roofer and agreeing the scope of work
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What goes beneath a roof covering and how to choose the underlay

A layer of underlay is laid beneath the roof covering to take over water that gets under the tiles or metal sheet, as well as condensation. When choosing the underlay, check whether it works with the selected covering, the pitch and the whole roof build-up, not just whether it has good parameters. Continuity of the system at the eaves, chimney and penetrations is also important. The underlay should not be confused with a vapour barrier or insulation. The method of support depends on the product, so verify the intended use of the membrane or rigid underlay and the requirements for vapour flow and ventilation.

By |2026-11-14T23:58:16+01:002026-06-08|Knowledge base|Comments Off on What goes beneath a roof covering and how to choose the underlay
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How to choose a contractor for an integrated photovoltaic roof?

The installer should understand both the roof and the electrical installation, or ensure well-organised cooperation between the two trades. The number of ordinary panels installed alone does not confirm experience with an active covering. It is worth checking completed projects, documentation, the quoting method and after-sales service. A good choice is not about finding the longest list of promises, but about assessing specific answers relating to your own building. Ask for examples of roofs completed in the system under consideration or in a solution of comparable construction. Not only drone photos matter, but also details at windows, chimneys and edges. If possible, it is worth seeing a finished building from a normal perspective.

By |2026-11-15T19:00:16+01:002026-06-06|Knowledge base|Comments Off on How to choose a contractor for an integrated photovoltaic roof?
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Designing roof valleys for drainage and appearance on complex roofs

A multi-pitched roof has many visible lines. Some are formed by ridges and hips, and some by roof valleys collecting water. The latter require particular attention. Their geometry should follow from the layout of the roof slopes and the method of drainage. The appearance can be tidied through the correct selection of flashings and careful finishing of the covering. However, the drainage path should not be narrowed merely to make the visible strip of sheet metal smaller. A single building may have roof valleys of different lengths and different angles. One collects water at a dormer, another connects large roof slopes. Their similar appearance on plan does not mean identical conditions. It is worth assessing each section in relation to the area from which water flows.

By |2026-11-15T03:59:24+01:002026-05-23|Knowledge base|Comments Off on Designing roof valleys for drainage and appearance on complex roofs
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Mansard roofs: how the change in pitch affects the loft and the detailing

A mansard roof has slopes divided into an upper part and a steeper lower part, giving the attic more convenient space at the walls. It is worth checking whether the geometry of both parts permits the chosen covering, especially on the gentler upper slope. The break detail, ventilation and fixings on the steep sections require the most attention. The designer should draw the break line and define how forces are transferred. The actual gain depends on the break height, construction thickness and insulation, so compare the finished cross-section rather than just the floor plan.

By |2026-11-14T23:57:28+01:002026-05-22|Knowledge base|Comments Off on Mansard roofs: how the change in pitch affects the loft and the detailing
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Insulating a loft to avoid cold roof slopes and damp

To avoid cold slopes and moisture, attic insulation must form continuous insulation, a tight inner layer and allow the roof to dry. Choosing a thicker board alone does not eliminate gaps at the wall plate, windows and rafters. First define the boundary of the heated part of the house: with an unused, cold attic, insulating the ceiling below may make sense, while when rooms are created, insulation must cover the slopes and other partitions. Check that the material type and thickness match the design, the layer is continuous, boards fit and joints are sound.

By |2026-11-14T20:15:03+01:002026-05-19|Knowledge base|Comments Off on Insulating a loft to avoid cold roof slopes and damp
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