How to prove you did the work (and that the damage was already there)

What makes a photo good proof

A photo only helps if it answers three questions: when was it taken, where, and has it been changed? A clear, stamped, original photo answers all three.

1. Take “before” photos of everything

Before you touch anything, walk the job and photograph what’s there. This is your proof that the damage was already there.

• A wide shot of the outside, with the house number or sign in view
• Every room or area you’ll work in, shot from the doorway
• Close-ups of damage that’s already there: cracks, stains, rot, dents
• A tape measure next to the damage, to show size
• Model and serial plates on old equipment you’ll replace
• The way in: driveway, floors, lawn and fences near the work

Point out old damage to the client while you’re there. If you can, take the photo while they watch.

2. During the job, shoot what gets covered up

Once the drywall goes up or the concrete is poured, nobody can see what’s under it. “During” photos prove the hidden work was done right.

• Pipes, wires and framing before the walls are closed
• Insulation before it’s boarded over
• Flashing, underlayment and fasteners before the shingles go on
• Labels, sizes and thickness of the materials you used
• Any surprise problem you find, before you fix it
• Anything the client asked you to change mid-job

3. After: match your “before” shots

Stand in the same spot and shoot from the same angle as your before photos. Side-by-side pairs are hard to argue with. Inspectors work the same way: TrustMark, which checks energy-efficiency work in the UK, asks for new photos “taken from the same angle and location wherever possible” as the originals.

• The finished work, both wide and close up
• Labels, settings and controls on anything you installed
• The clean site, with your tools and waste gone
• The way in, to show you left it as you found it

4. Put the date, time and address on the photo

Your phone saves the time and place inside the photo file as hidden data. But hidden data is easy to lose. On iPhone, for example, you can turn location off in the share options with one tap. And nobody can see hidden data on a printed photo.

That’s why the details should be on the photo, where everyone can see them. A timestamp camera such as TradeStamp burns the date, time, street address and GPS into the image when you take it, so the stamp stays on wherever the photo goes.

One tip: a stamp is only as good as your phone’s clock. Keep automatic date and time turned on.

5. Keep the original files

Never edit, crop or filter a proof photo. If you want to draw arrows on one, make a copy and keep the original.

• Back up your photos at the end of every day.
• Don’t rely on photos sent by text or WhatsApp. Messaging apps often shrink them.
• Keep job photos for as long as anyone could ask about the job, such as your warranty period.

To prove a file hasn’t changed, you can use a fingerprint, called a hash. A SHA-256 hash is a long code worked out from the file. Change one pixel and the code changes. The US standards agency NIST says hashes are used “to detect whether messages have been changed.” TradeStamp records a SHA-256 fingerprint for every photo the moment it’s taken and lists them in its reports.

6. Send a report the same day

Don’t wait until the invoice is late. Send the photos while the job is fresh.

• Put the before, during and after photos in order, with a short note on each.
• Send it by email, so you both have a dated copy.
• Attach it to your invoice.
• Ask the client to reply if anything looks wrong.

A report sent on the day says “here’s what I did” before anyone has a reason to argue.

7. Get a sign-off

Walk the finished job with the client. Ask them to sign and date a line saying the work is complete. If they won’t sign, write down what they said and email them a short summary the same day.

If they raise a problem, photograph it, write down what you agreed to do, and add it to the job.

The quick checklist

1. Before photos of the whole site and any old damage
2. During photos of anything that will be covered
3. After photos from the same angles
4. Date, time and address on every photo
5. Original files kept and backed up
6. Report sent the same day
7. Client sign-off, or an email summary