A tax break is a deduction in your tax bill.
Sometimes, the government will allow you to claim deductions if you spend on certain things - these are usually called tax incentives.
There may have been a policy that lets you claim back some of the cost of the renovation, by reducing your tax bill.
So for the renovator, if they spent £100 on renovation, they'd be able to claim a tax break, reducing their tax bill by £65. So it's only really costing them £45 for £100 worth of renovation. In that sense, it's reducing the cost of renovation for them.
That's my take on it.