Feel like I might be missing something here, advice welcome.
We don’t have enough space in our current home atm. When our fixed term is up LTV should be about 50%. The cost of an extension to get the space we need at current costs (which have rocketed) is probably about half our equity, so we’d need to remortgage to pay for that and our LTV would go down to 80% (of existing house value). I think the extension would increase the value but we wouldn’t make any money on it and we might just about break even, plus factoring in all the disruption and sunk costs on things like renting somewhere for part of the time. We wouldn’t be able to remortgage to factor in the increase in house value probably for a couple of years.
Alternatively, if we sell, we release that 50% equity which means we have a sizeable deposit. My salary has increased so we could borrow a lot and could afford a house with a much bigger footprint. Monthly payments would increase but not significantly more. Sunk costs would obviously be stamp duty and moving costs.
I can’t decide what makes more sense. I can give the amounts involved if helpful. Kids are 4 and 2 so high childcare costs atm which will reduce soon.