Methodology

This page explains two things: how the roof drawing works and how we write the guides. That way you know what to expect from each and what not to.

Last updated: 2 November 2026.

What the roof drawing does

The drawing is a simple elevation of the house, made from what you type: the covering (ceramic tile, sandwich panel, fibre cement or “I do not know”), the roof shape (2 or 4 slopes), the number of floors, the front and depth of the house in metres and the slope.

• The roof area is a geometric calculation: (front + 1 m) × (depth + 1 m) ÷ cos(slope). The extra 1 m is the eaves, 0.5 m on each side. It is an estimate to give you the order of magnitude.
• The drawings and dimensions (eaves and ridge heights) follow the same sizes. It is a diagram to show the type and proportion, not a project.
• The problems you mark (“water gets in”, “broken tiles”, “moss”, “cold house”) appear as clouds on the drawing. They are there so that the request says what is wrong. They are not a diagnosis.
• The reference price shows as “to be confirmed”. We do not show prices yet: we will only do so when we can justify the values with a dated source.

What the drawing does not know

Many things decide what a roof needs and do not pass through a form:

• the real state of the tiles, battens, underlay and structure, which can only be seen on site;
• the exact origin of a leak, which is often far from the stain;
• access (floor, scaffolding) and removal of materials;
• the type of fibre cement and whether it contains asbestos;
• VAT and the conditions of the work.

So whoever fixes a price without seeing the roof is guessing. Use the drawing to organise the description and always ask for a visit and a written quote.

What happens to what you type

What you describe in the drawing stays in your browser until you send something. When you send the form, we store the description together with your name, phone number and town. Details are in the Privacy policy.

How we write the guides

1. We start from a real question from someone with a roof: where a leak comes from, whether fibre cement contains asbestos, whether a permit is needed.
2. We look for sources. We prefer the Diário da República, ADENE, Fundo Ambiental, IPQ, ACT, LNEC, municipalities and dated manufacturer data sheets. Price websites and forums are only an indication, never proof.
3. We write in European Portuguese, in plain words. We explain each technical term the first time it appears.
4. We cite the sources and the date we read them.
5. We give no prices without a source. When we talk about cost, we explain what pushes it up or down. We only give values if they come from a source we name, with the date we checked.
6. We say what we could not confirm. If we found no reliable source, the text says it depends and what to ask whoever does the work, instead of stating.

The role of artificial intelligence

We use artificial intelligence tools to help research, organise and draft, and to generate the images, which are always marked “Illustration”. What goes on the site is checked against the sources we cite. We do not claim the guides were reviewed by an engineer or architect. They are general information, written with care, and do not replace the opinion of a specialist or a visit to a roof.

Independence and limits

• We do not do roof work. We do not recommend brands or companies in the guides.
• At the moment we do not forward requests to companies. If that changes, we will say so here and in the Privacy policy, and ask for new consent.
• Rules and standards change. When we talk about legislation, we give the date we read the source. Always check the official site before deciding.

How to ask for a correction

Did you find an error, outdated information or a sentence that is unclear? Write to [email protected] with the page address and what is wrong. If the error is ours, we correct it and update the page.