I posted in chat to canvas a range of views.
Our house needs some significant renovation, some basic, some more significant. We are considering increasing our mortgage from 17% of our take home to 22.5% which is a fairly significant jump. We can afford it but it would be tighter than we're used to.
The money would be used to add a kitchen extension (including downstairs loo and utility) replaster large parts of the house, replace the currently unuseable second bathroom and replace the boiler.
Should we do it? We've both got stable jobs.