Negative keywords are one of the most underused tools in Google Ads — and one of the most valuable. While most construction businesses focus exclusively on which keywords to target, the keywords you exclude are often equally important for controlling spend and improving lead quality. A construction Google Ads account without a solid negative keyword strategy is almost always wasting a meaningful portion of its budget on irrelevant clicks.
Here's a practical guide to using negative keywords to stop your construction Google Ads budget being absorbed by searches that will never produce a lead.
Why negative keywords matter for construction ads
When you bid on keywords in Google Ads, you're not just buying exact matches — you're buying variations, synonyms, and related terms depending on your match type settings. Broad match keywords in particular can trigger your ads for a surprisingly wide range of searches, many of which have nothing to do with what you offer. Without negative keywords to block irrelevant searches, your budget gets diluted across clicks that will never convert.
For construction businesses, this problem is particularly acute. Words like "building," "construction," "fencing," "plumbing," and "excavation" all have multiple meanings and attract searchers who are looking for jobs, DIY guides, equipment to buy, courses to enrol in, or information about unrelated industries. Every time one of these irrelevant searchers clicks your ad, you've paid for a click with no chance of becoming a lead.
The most common wasted-budget culprits
Across construction Google Ads accounts, the most common categories of wasted spend from missing negatives are: job seekers ("construction jobs," "[trade] apprenticeship," "[trade] salary," "jobs near me"), students and researchers ("construction course," "how to become a builder," "building diploma"), DIY searchers ("how to [service] yourself," "DIY [service]," "[service] tutorial"), equipment and material buyers ("construction equipment for sale," "[materials] supplier," "Bunnings"), and unrelated industry terms that happen to share your keywords.
For specific trades, common irrelevant search variants multiply quickly. A concreting company bidding on "concrete" without negatives will pick up "concrete paint," "concrete sealer," "concrete mixer hire," "concrete poetry," and a dozen other irrelevant variations. A landscaping business bidding on "landscaping" will pick up "landscaping jobs," "landscaping courses," "landscaping ideas" (informational, not ready to buy), and "landscaping supplies." Each of these represents budget spent on a click that has virtually zero chance of becoming a client.
How to build your negative keyword list
The fastest way to build an initial negative keyword list is to run your campaign for a short period and then audit the Search Terms report in Google Ads. This report shows you the actual search queries that triggered your ads — not just the keywords you bid on, but the real searches people typed. Go through it systematically and identify any search that isn't from a potential buyer looking for the service you offer. Add each irrelevant category to your negative keyword list.
Before you even launch, build a starter negative list from industry common sense. For any construction trade, standard starter negatives include: jobs, employment, career, apprenticeship, course, training, school, university, TAFE, salary, wages, hire (if you don't offer hire), rent, buy, for sale, wholesale, supplier, materials, DIY, how to, tutorial, template, software, app, and any unrelated uses of your primary keyword.
For specific service categories, add relevant variants: for fencing — picket, pool (if you don't install pool fencing), DIY, panels, paint. For earthmoving — toys, games, simulator, jobs. For plumbing — parts, supplies, training, apprentice, course. Your initial list should have 50–100 negatives as a minimum before you spend a dollar on a new campaign.
Match types and where to apply negatives
Negative keywords in Google Ads work differently to positive keywords. A negative exact match ([keyword]) will only block searches that exactly match that term. A negative phrase match ("keyword") will block searches that contain that phrase in any order. A negative broad match (keyword) blocks searches containing all the words in any order — but be careful, as negative broad match can accidentally block legitimate searches if you're not precise.
For most construction businesses, negative phrase match is the right default for most negatives — it blocks variations of a term without being so broad that it accidentally excludes relevant searches. Apply your highest-priority negatives at the account level using a shared negative list (this applies them across all campaigns automatically). Apply service-specific negatives at the campaign level so you're not inadvertently blocking relevant searches in campaigns where those terms might be appropriate.
Ongoing review and maintenance
Negative keyword management isn't a one-time setup. New irrelevant search terms appear constantly, particularly as your campaigns mature and Google's Smart Bidding algorithms broaden the search terms they're matching. Set a monthly calendar reminder to review the Search Terms report for each campaign, identify new irrelevant search patterns, and add the relevant negatives.
A well-maintained negative keyword list is one of the highest-return maintenance tasks in Google Ads. It directly reduces wasted spend, improves your campaign's click-through rate (because your ads only show to relevant searchers), and improves your Quality Score — which in turn lowers your cost-per-click and improves your ad position. Ten minutes a month reviewing search terms pays for itself many times over.
Constructiv Digital manages Google Ads campaigns for construction and trade businesses across Australia, including comprehensive negative keyword management. If you'd like to discuss the efficiency of your current campaigns, get in touch with our team.
