Not the property ladder fallacy again. There is no ladder unless you expect to earn significantly more in the future than you do now.
I’ve used this example before. You buy your first house for £200k, borrowing £180k. After five years on a 25 year mortgage you might have paid off £10k of the capital; interest on a repayment mortgage is front loaded. On a longer mortgage term, you’ll have repaid less capital.
Your house has gone up in value during those five years by 20%, to £240k. Your equity is £70k: current value less the £170k you still owe on the mortgage.
The house you want to buy next cost £400k when you bought your £200k house. It, too, has gone up by 20% and now costs £480k. To buy it, you will need to borrow £410k. £480k less your £70k equity from house number one. And you’ll need to find the stamp duty, which you can’t borrow.
Who is going to lend you twice as much as your original mortgage, five years on? Will your salary have doubled in five years? Unlikely. So your ‘trading up’ will involve borrowing a shedload more, on a longer mortgage whose term restarts when you move to the new house. You can forget going part time, as well: there’s a big mortgage of £410k to be serviced. Forget retiring before state pension age: to borrow £410k you’ll need a long mortgage term, which will necessitate working well into your sixties. Your massive mortgage will vacuum up your disposable income at the expense of pension contributions that might buy you a more comfortable retirement. And you’re very exposed to interest rate increases.
Property ladder? Sounds more like a property snake to me.