There is no requirement to be a limited company to register with HMRC for VAT.
You must register for VAT is your turnover is over £85,000, but you can register at any turnover if you wish.
However this is entirely independent of registering your company with Companies House.
Admittedly if your turnover is over £85,00 and you are not a limited company then a loss of income could cause significant personal difficulties if your house has to be sold to pay the debts.
I was / am , a sole trader , was VAT registered for years , registered voluntarily because all my customers were commercial / industrial and complained they couldn't reclaim VAT from my invoices . I'm not registered now .
Absolute pants for any domestic work though. , forget it .