Questions to ask before painting or waterproofing work

You've spotted the first crack in your bathroom ceiling and you're staring at a quote from a painter. Before you sign it, you need to know what you're actually paying for — and whether the person holding the brush understands what's underneath the problem. The right questions now will save you from watching paint peel within months, or water seeping back through your walls before winter ends.

Questions that reveal whether they've diagnosed the real issue

Start by asking: "What's causing the damage you'll be treating?" A painter who launches into their product range or timeline without first establishing the root cause is guessing. If there's dampness, they should explain whether it's rising damp from the foundation, penetrating damp from a leaky roof, or condensation. If it's flaking paint, they should tell you whether the substrate is sound or if there's underlying decay.

A good answer sounds like this: "I'll need to check the wall for moisture levels before I start. If it's damp, we treat that first — no point painting over wet plaster." An evasive answer is vague: "It just needs a fresh coat" or "These products handle most issues."

Next, ask: "What preparation will you do, and how long will it take?" This matters because prep is where the job is won or lost. They should describe scraping, sanding, filling, or removing loose material. They should mention priming. If they brush past prep or call it "just a light clean," move on. A contractor who quotes a three-day job for a room that needs plaster repair and mould treatment is cutting corners.

Ask also: "Will you test the surface before you start?" For waterproofing especially, this shows they're serious. Moisture meters exist. Adhesion tests exist. A painter who skips these is gambling with your money. The answer should include specific tools: "We'll use a moisture meter to check the wall, and we'll do a pull-off test to see if old paint is bonded properly."

Another key question: "What products are you using, and why those?" Don't accept "good quality paint" as an answer. Push for specifics: the brand, the product line, the finish type. For waterproofing, they should name the membrane or sealant and explain why it suits your particular problem — exterior concrete behaves differently from bathroom tile, which is different again from a roof. If they say "I use what works," ask them to name it and let you verify it yourself.

Questions that protect you from hidden costs and broken promises

Ask: "What's included in your quote, and what's not?" A detailed quote lists surface preparation, primer, undercoat, topcoat, sealants, and labour. If yours just says "painting: R X," request a breakdown. Hidden costs appear when they discover rotten timber, previous botched repairs, or asbestos-containing materials that need professional removal. A transparent contractor will explain their terms: what happens if prep reveals extra work, and how cost changes are approved.

Ask: "Will you provide a written guarantee?" This is critical for waterproofing. The answer should include specifics: what the guarantee covers, how long it lasts, and what voids it. A guarantee worth its paper should exclude only normal wear and settling cracks, or damage from impacts or poor maintenance. Be suspicious of "lifetime" guarantees without detail — they often mean nothing. If they say "I stand behind my work," insist on a signed document specifying the timeframe and conditions.

Finally, ask: "Can I contact someone you painted or waterproofed in the last year?" References matter. A genuinely skilled contractor will have recent clients who can speak to whether the work lasted, whether the painter cleaned up properly, and whether they honoured the timeline. If they hesitate or offer only old jobs, that's a warning.

These six questions — about diagnosis, preparation, testing, products, itemisation, and guarantees — form a quick filter. A painter who answers them clearly and without defensiveness is someone who understands their trade. On Strove, you can compare verified painters and see their reviews alongside their credentials, which keeps you from having to chase down references yourself.