Survey costs
A friend says take ten percent off for every rating 3. Why is that percentage not a published repair cost?
Because that percentage is not a published repair cost. A friend who says take ten percent off for every rating 3 is offering a private rule of thumb. RICS has not published it. The report has not printed it. It is not the cost of those defects. Do not deduct it. Do not tell the seller the survey requires it. If you need a number, get contractor quotes for the actual work. The percentage is not a stand-in for those quotes.
Last reviewed 24 October 2026. Written for buyers in England and Wales unless this answer says otherwise. No named surveyor has signed this page. It is general guidance, not a report on your house, and not legal advice.
What is the fuller explanation?
Rules of thumb spread because they are easy to say in a kitchen and impossible to pin on a particular gutter, wall or chimney. A house with one serious roof defect and a house with one serious boundary wall do not share a cost just because both paragraphs were serious. The guidance explains surveys. It does not publish a percentage of the purchase price, of the valuation, or of anything else, as the price of a rating. Using your friend's percentage presents a fiction as a repair cost. The repair cost is whatever a contractor will charge for a described scope, or it is unknown.
You can still decide the defect is more than you will take on. That is a judgement. It becomes misleading when you write to the agent that official guidance knocks ten percent off per item. Official guidance does no such thing. There is no national tariff expressed as a percentage. If several ratings are serious, you have several reasons to seek quotations, not several copies of the same unofficial discount. Keep the friend's method out of the legal papers. Put quotations in, or put nothing and say the cost is not yet known.
What should you ask your surveyor?
- Have you published any percentage as the cost of a rating?
- Which serious items actually need their own quotations?
- What would be wrong with treating one percentage as every defect?
What are the typical next steps?
- Refuse the ten percent rule as a repair cost.
- Get quotations for the serious items.
- Do not write your friend's percentage into an offer as if it were official.
Costs vary with the building and with who you instruct. Where this page does not cite a published figure, ask the surveyor, a relevant specialist, or your solicitor for a written quote. Do not treat a forum average as the price.
Also asked about this
If every friend uses the same percentage, has it become a tariff?
No. Repetition is not publication by RICS. The percentage is still not a repair cost.
Can I use the percentage only as a private worry, not as a cost?
You can feel cautious without naming a false cost. The moment you call it the repair cost, you have gone beyond anything published.