Editorial Policy

This site publishes cost figures that people take into negotiations with contractors. That is the whole reason for the rules below, and the reason they are written down where you can hold us to them.

How a cost figure gets onto a page

Every number is traced to a named, dated, published source before it is written down. We do not estimate, interpolate between real figures, or round a sourced number into a tidier one.

Sourcing is not the end of it. Every value in our cost model carries a verification status, and only one of them can be published:

• Verified — somebody opened the cited source and the number matched. This is the only status that renders a figure on this site.
• Unverified — we have a citation but nobody has confirmed the figure against it, usually because the publisher blocks automated reading.
• Disputed — two or more sources give materially different figures, or one source contradicts itself.

Unverified and disputed values render as a visible gap with no number at all — not a figure with a caveat. A figure nobody has checked is as dangerous as one nobody sourced, because it gets used the same way. A build-time test enforces this, so a withheld figure cannot reach a page by accident.

Arithmetic we perform is labelled as ours. A payback period, a cost build-up, a per-foot rate divided out of a box price — those are calculations, not published statistics. We show the inputs and the working so you can redo them.

How pages are reviewed and updated

Each page carries a last reviewed date. That date only changes when the content actually changes. We do not restamp pages to look fresh.

Cost data is rechecked periodically against its sources, and when a figure moves, the page moves with it. When new evidence overturns something we have published, we rewrite the page rather than quietly adjusting a number — and where the change is significant, we say what changed and why.

We correct in public. If we have published something wrong, the fix says so.

What we will not do

• Publish a price we cannot source.
• Recommend a product we have no basis for comparing.
• Present a figure from a party with a commercial interest in the answer without saying who they are and what their interest is.
• Gate a cost result behind an email address.

Where a number is missing, the page says it is missing and says why. That is often the most useful thing on it.

Advertising and affiliate relationships

As of the date at the top of this page, this site carries no advertising, no affiliate links, and no sponsored content. Nothing here earns a commission.

If that changes, these rules apply and this page will be updated before it does:

Disclosure sits next to the link, not only in a footer. If a link earns us money, you will be told so above it, in plain language, without expanding anything.

Commercial relationships do not decide what we say. No advertiser or affiliate partner gets review of a page before it publishes, and no figure gets softened because of who sells the product. Where we think something is not worth buying, we say so — including about products we might earn from.

Cost figures are never affected. Our pricing comes from published sources and from suppliers’ own listings. A commercial relationship cannot change what a source says, and it will not change which sources we use.

Who writes this

Our expertise is rigorous data compilation and honest reporting of what the sources say — not thirty years on a roof. We say so plainly on about, and it is why the methodology is published rather than asserted.

The full source list, the verification status of every value in the cost model, and the gaps we have not closed are on how we calculate costs.

Telling us we are wrong

If a figure here looks wrong, or you have a better source than the one we used, we want to hear about it — a correction is worth more to this site than a page view. Get in touch via contact.