Skylight or sun tunnel: check the whole roof project

Start with the actual ceiling and roof

Gather interior photographs and any existing drawings without climbing onto the roof to obtain them. Mark the room, the dark area and known obstacles. Arrange a check of the structure, pitch, outer covering and existing layers. The proposal should identify which elements would change and who will design that work before an opening is selected.

Record known services, chimneys, equipment and sources of shade. An apparently clear ceiling position may align with a beam or service above it. Where a void separates ceiling and roof, ask for a section showing the whole route. This makes alternatives comparable and exposes uncertainties that a price per window can conceal.

Connect the product to the task below it

A sun tunnel directs daylight from the roof to an interior diffuser; it does not provide the same experience as a view. In a passage, identify where you need to recognise objects or find a doorway. In a workspace, also mark the desk and screen. The centre of the ceiling is not automatically the most useful position.

Have each proposal identify an exact model and explain how you will use it. If opening matters, check the controls, movement of the sash and operation while you are away. Keep electric lighting for times and conditions without daylight.

Source: VELUX · Tubos solares

Plan shading before increasing glass area

Write down when you use the room, where sunlight falls and which surfaces create troublesome reflections. Request an assessment of orientation, outside obstructions and shading with the intended furniture layout. VELUX distinguishes exterior heat protection from interior blinds. Specify darkness for sleeping and control of incoming heat as separate requirements in your brief.

Spain’s CTE DB-HE relates thermal requirements to climate and project scope, including condensation risk. Ask for the complete solution to be assessed for your property rather than applying a universal saving percentage. Establish how shading will operate when nobody is home and what happens if its power or connection is unavailable.

Source: VELUX · Protección exterior del calor · CTE · Documento Básico HE Ahorro de energía

Request a drawing of the roof junction

CTE DB-HS addresses protection against water at skylight junctions. For your proposal, request a drawing showing the frame, waterproofing and insulation continuity. Identify the existing layers to be lifted, those to be replaced and the reinstatement of the outer covering. The word “sealed” alone does not describe the assembly you are buying.

VELUX resources provide access to product instructions and technical documents. Ask for those matching the proposed model, pitch and roof covering. Agree who coordinates the boundary between trades and when concealed layers will be photographed. Also establish how the outside will be inspected and cleaned with a planned safe means of access.

Source: CTE · Documento Básico HS Salubridad · VELUX · Instrucciones por producto

Resolve the procedure before confirming the order

Ask the local ayuntamiento which procedure and documents apply to this particular opening. Provide the address, photographs, proposed dimensions and any intended structural change. For a shared building, clarify the roof’s status and necessary agreements with the owners’ community. Do not infer the procedure simply from the commercial size of the window.

Make the order depend on a documented decision about feasibility and scope. Ask whether protection of the building or its surroundings affects the design. Record who prepares and submits each document and what must be resolved before work begins. An answer about another property or municipality does not establish the position for yours.

Source: Ayuntamiento de Madrid · Licencias urbanísticas y declaraciones responsables

Compare the complete scope and plan handover

Here is a hypothetical arithmetic exercise, not market pricing: a €3,000 allowance could comprise €1,800 for the assembly and installation, €450 for access, €300 for interior finishes, €250 for shading and €200 for documentation and administration. The total illustrates categories to review. It does not predict the cost of your project.

For actual proposals, check taxes, removal, protection of the home and any structural work. Keep unpriced items visibly unresolved. At handover, try the opening, controls and shading, inspect finishes and collect product references, instructions, warranties and junction photographs. Agree who to contact about problems and how maintenance can be carried out with appropriate access.