Damp proofing cost calculator: what the job involves and who is registered to do it

How damp proofing cost calculator works

1. Measure the runs in metres. Walk the affected walls with a tape and write down each run separately, internal partitions included if they are being treated. That list is the input every per-metre rate multiplies, and it is the number a quote is easiest to check against.
2. Work out the plaster area. Multiply each run by the height the surveyor has specified for plaster removal. That area, not the floor area of the room, is what the replastering line is priced on, and halving the height nearly halves the largest number on the quote.
3. Add the fixed lines. Survey fee where it is not refunded, skip or waste disposal, and any structural work the survey found. These do not scale with wall length and are the reason a very small job is rarely very cheap.
4. Add what is excluded, at somebody else's rate. Decorating, skirtings, carpets lifted and relaid, and any electrical work to move sockets. Price these separately rather than pretending they are not part of what the job will cost you.
5. Then compare, line for line. Two quotes are comparable once they are broken into the same four groups. Where they differ it is nearly always the plaster height or the number of runs, and both are things you can ask about with a tape measure in your hand.

Insurance and paperwork

Common questions

Why does this page not give me a price?

Because a single national figure would be a worse answer than the method. The rates that matter are the ones in the quote in front of you; the arithmetic here is what turns them into a total you can check and challenge.

What measurement do damp contractors actually use?

Linear metres for the injected course and square metres for the plaster. If a quote is expressed only as a lump sum, asking for those two units is a reasonable request and a straightforward firm will give them to you.

Does the calculation change for a solid wall?

The plaster side does. Solid brick or stone walls hold more moisture and take longer to dry, so the specified removal height and the drying programme are usually greater, and the replastering line grows with them.

Registered contractors by region

• Registered roofers in the East Midlands postcode area
• Registered roofers in the East of England postcode area
• Registered roofers in the London postcode area
• Registered roofers in the North East postcode area
• Registered roofers in the North West postcode area
• Registered roofers in the Scotland postcode area
• Registered roofers in the South East postcode area
• Registered roofers in the South West postcode area
• Registered roofers in the Wales postcode area
• Registered roofers in the West Midlands postcode area
• Registered roofers in the Yorkshire and The Humber postcode area