Warming up
Transactional email API
6,308 construction companies in the UK publish an email address on their own website, as of September 29, 2026. Microsoft 365 handles email for 10% of them, and 11% name London on their website, more than any other UK city.
Searching is free. You only spend allowance when you export.
Counted by the city each company's own website names. London leads with 716; a company that names two cities counts in both.
| London | 716 (11%) |
|---|---|
| Manchester | 106 (2%) |
| Bristol | 99 (2%) |
| Nottingham | 83 (1%) |
| Birmingham | 66 (1%) |
| Glasgow | 65 (1%) |
| Edinburgh | 65 (1%) |
| Leeds | 58 (under 1%) |
| Southampton | 47 (under 1%) |
| Sheffield | 43 (under 1%) |
Of the 968 that print a Companies House number, 95% are registered in England and Wales, 5% are registered in Scotland and under 1% are registered in Northern Ireland.
Every company here publishes an email address. These are the other routes and signals their websites carry.
A second route for when email goes unanswered.
Growing firms buy more. A useful first filter.
Some sites tell search engines exactly what kind of business they are, in structured data. These are the types they declare most often, which shows the mix inside this category.
| Home and construction business | 3,026 (48%) |
|---|---|
| General contractor | 696 (11%) |
| Roofing contractor | 351 (6%) |
| House painter | 79 (1%) |
| Professional service | 13 (under 1%) |
Who hosts their email decides which spam filter reads your message. What their site is built on says what else they already pay for.
| Microsoft 365 | 646 (10%) |
|---|---|
| Self-hosted | 273 (4%) |
| Google Workspace | 268 (4%) |
| IONOS | 105 (2%) |
| Other or unknown | 5,016 (80%) |
Read from each domain's public MX record. If most of your list is on one provider, warm up a mailbox on that provider first. Filter by provider in the lead finder.
Share of these companies whose homepage loads each technology. Google Analytics is left out because nearly everyone runs it.
1,239 of them (20%) state a founding year on their site. This is how those split.
| Before 1980 | 180 (15%) |
|---|---|
| 1980 to 1999 | 422 (34%) |
| 2000 to 2009 | 314 (25%) |
| 2010 to 2014 | 152 (12%) |
| 2015 to 2019 | 128 (10%) |
| 2020 or later | 43 (3%) |
What we have learned about emailing construction companies. The numbers above tell you how many there are; this is how to get a reply.
Contractors are practical and short on time at a desk. Keep it to three lines, lead with money or hours on site, and make the next step a phone call rather than a demo link.
Hi [first name], most builders we speak to send plenty of quotes but lose track of the ones that go quiet. We help firms like [company] follow up automatically so more quotes turn into jobs. Worth a quick call this week?
Replace the bracketed parts per company. In a Warmerly campaign they fill from the lead's own fields.
Early morning, 6:30 to 8am, before crews start, or early evening. Midday email is read on a phone on site, if at all.
Warmerly's lead database holds 6,308 construction companies in the UK that publish an email address on their own website, counted on September 29, 2026. That is not every such business in the country. It is the ones whose site we crawled and that list a way to contact them by email, which is the number that matters for outreach.
Microsoft 365 runs email for 10% of them, followed by Self-hosted at 4%. It is read from each domain's public MX records. It matters for cold email because Google and Microsoft filter differently, so a sending mailbox on the same provider as most of your list is worth warming up first.
London, named by 716 of them, then Manchester (106) and Bristol (99). The count is companies whose website names the city, so one business can appear under more than one.
Yes. Searching the database in Warmerly is free, and you see the same count as this page before spending anything. Exporting or adding companies to a campaign uses your plan's monthly lead allowance. Every result is a business contact route the company publishes itself, and any company that has asked to be removed is excluded. This page shows totals only, never individual companies.
Filter them by size, founding year, technology and hiring, see what each record holds, then send from warmed-up mailboxes in the same tool.
