Non-standard construction
Brickwork is cracked beside an exposed Hawthorn Leslie member and the surveyor calls it rust. What section loss has that crack not measured?
The crack has not measured any section loss in the Hawthorn Leslie member. Rusting steel expands and can jack the brick beside it, which is why the surveyor links the crack to rust. Expansion explains a mechanism. It does not give the remaining thickness of the steel, the depth of the scale, or how much of the original section is left. The survey has seen cracked brick and an exposed member it calls rust. It has not gauged the steel, opened the rest of the frame, or decided how much metal has been lost.
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?
Hawthorn Leslie houses use a steel frame, and the members that sit in or against the brick can corrode where moisture reaches them. As rust occupies more space than the steel it replaces, the joint can crack and the brick can lift or split. That pattern is a reason to take the member seriously. Crack width still is not a ruler for the steel. Two cracks of similar look can sit beside very different remaining sections, and only the exposed member was available to see.
A steel-frame specialist can measure the exposed member and advise which other lengths should be opened, as work beyond this visit. Tell the solicitor the report links the crack to rust and does not contain a section-loss figure. Do not treat the word rust as a calculation of what remains, and do not assume the hidden members match the one that was exposed. The survey has not specified a repair or a replacement.
What should you ask your surveyor?
- Which Hawthorn Leslie member was exposed, and which faces of it did you actually see?
- Are you linking the brick crack to rust without a measurement of remaining steel?
- Which neighbouring members were still covered and therefore not assessed?
What are the typical next steps?
- Treat the crack as a rust clue, not as a measurement of section loss.
- Ask a steel-frame specialist what opening up and gauging would involve.
- Tell the solicitor the report does not contain a remaining-thickness figure.
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 the crack is only in the mortar, is the steel unaffected?
Not on this evidence. A mortar crack beside an exposed member the surveyor calls rust is still a crack next to corroding steel. The report has not said the member is intact. It has also not measured how much section has been lost, so a crack that stays in the joint is not a clearance.
Can a coat of paint stand in for the missing measurement?
No. Paint would hide the surface the surveyor could see. It would not record how much steel remains under the scale, and it would not inspect the members that were never exposed. The survey called the condition rust. It did not measure section loss, and a later coat of paint does not create that figure.