Rooflight Guides

Written to be useful before you buy anything

These guides set out how rooflights actually work, what the numbers on a specification sheet mean, and where installations go wrong. They are written so that somebody reading them could hold a competent conversation with any installer, including one who is not us. That is deliberate. A customer who understands why an upstand height matters is a customer who is easy to work with and hard to sell the wrong thing to.

Nothing here is gated behind a form and nothing here changes if you never call. If a guide answers your question completely and you go on to fit the unit yourself or use somebody else, it has done its job.

Where to start

If you are at the beginning, read the sizing guide and the one on flat against pitched roofs. Between them they settle what will physically go into your roof and roughly what it will cost, which is what most people actually want first.

If you have had a quote and want to check it, the guides on upstands, flashing and glazing specification are the ones to read. They cover the four details that decide whether a rooflight stays dry, all of which are invisible once the job is finished and none of which appear on a typical quotation.

If the problem is an existing unit that has failed, start with the guide on replacement. The decision there is rarely about the glass. It is about whether the opening and the timber around it are still sound enough to carry a new unit, which is a survey question rather than a catalogue question.

Guides against answers

A guide takes a subject and works through it properly. The answers section takes a single question and answers it in a few hundred words. If your question is narrow and specific, look there first; if you want to understand a subject rather than settle a point, the guides are the longer read.