Preferred source categories
When external context is needed, we draw from reputable, official or widely recognized publishers. The list below names categories rather than every URL — specific links appear on the pages that cite them.
- Official government agencies and national statistical offices.
- Eurostat — European Union statistical office.
- U.S. Census Bureau — including the Building Permits Survey and the Construction Spending series.
- International Energy Agency (IEA) — including the Buildings sector pages.
- United Nations Environment Programme (UNEP) and the Global Alliance for Buildings and Construction (GlobalABC).
- U.S. Department of Energy — including the consumer-facing Energy Saver resource.
- U.S. Federal Emergency Management Agency (FEMA) — for resilience and drainage context where relevant.
- U.S. Occupational Safety and Health Administration (OSHA) — where workplace-safety context is relevant.
- U.S. Federal Trade Commission (FTC) consumer advice — where consumer due-diligence context is relevant.
- OECD and World Bank — for international economic or housing context.
- Official building or local authority sources where appropriate.
Sources we do not use
We avoid sources that do not meet the standard of reputable, verifiable context. In particular:
- Random or low-quality blogs.
- Unverified contractor marketing pages used as if they were authorities.
- Aggregator sites whose underlying source is unclear.
- Invented citations or fabricated source titles.
- Broken or paywalled-without-context links presented as evidence.
Broad sources are background context, not local proof
Even reputable sources can be misused. Build Design Hub treats broad national and international sources as background context — useful for explaining how a topic works at a sector or country scale — not as proof of what is allowed at any specific address.
Permit, code, licensing and safety rules vary by jurisdiction. Where a project needs a local answer, the source is the local building authority, not a national statistic.
How sources appear on the site
Pages that cite external sources include a visible "Sources and further reading" section. External links open the publishing organization in a new tab.
- Sources are labelled with publisher and (where useful) a one-line note describing why they appear.
- Source links are not used to back exact prices, lifespans or local rules unless the source directly supports them.
- Pages without external sources are practical evergreen content — they rely on plain explanation rather than borrowed authority.
Errors and updates
If a source becomes outdated, broken or stops supporting the claim it appears beside, the citation is updated or removed. Material changes appear in the public /changelog.
Readers who spot a source problem can write to info@helperg.com.