New builds and warranties
Hairline cracks are in the new render. Has the survey proved structural movement?
No. The survey has not proved structural movement. Hairline cracks in the new render are a surface note on a new plot, and fine cracks in fresh render can come from shrinkage as the coat cures, from a joint behind it, or from movement. This visit did not monitor the cracks, did not open the render, and did not decide a cause. NHBC describes Buildmark as a 10-year warranty and insurance product. The survey does not open a claim and does not sort the cracks into a warranty stage. Movement is not proved.
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?
New render often shows fine cracking while it dries and while the background settles into its own small changes. That pattern is not, on its own, a leaning wall or a failed foundation. The survey can record where the lines sit and whether they are wide enough to see. It cannot turn a hairline into a diagnosis without opening up or monitoring, and neither was done. Calling it structural because the house is new would over-read a finish. Calling it nothing at all would ignore a mark that is there.
Photograph the lines if you are speaking to the builder or a warranty provider, and keep any claim you choose to make outside this survey. The visit has not opened a Buildmark claim and has not proved movement. Do not tell a lender the plot is moving, and do not tell them the render is insignificant, as if the survey had monitored it. Say hairline cracks were seen and the cause was not established.
What should you ask your surveyor?
- Has structural movement been proved from the hairline cracks?
- Were the cracks monitored or the render opened?
- Has this visit opened a Buildmark claim about the render?
What are the typical next steps?
- Treat movement as unproved.
- Keep any warranty conversation outside this survey.
- Do not tell a lender the plot is moving or that the lines were monitored.
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
Do hairline cracks always mean the render should be hacked off?
No. The survey has not chosen a repair and has not proved a cause. Hairline cracking can be a finish issue, and it can be something else, which is why the cause stays open. Hacking render off would be works, not a finding. Do not let a worry about the coat become a specification this visit never wrote.
Does a new plot put every crack inside the warranty automatically?
No. NHBC describes Buildmark as a 10-year warranty and insurance product, and the survey does not open a claim or decide that a crack is covered. Newness is not a claim. The hairline lines were recorded and movement was not proved. Any approach to the provider is your later step, with the policy papers, not a result of this visit.