Remortgaging for a house extension

[nondomesticgoddess]

I'm hoping someone will help me understand how this could work. The situation is hypothetical (and if possible, some time in the future).

So, we bought a house recently for just over £400k. We would like to put an extension on it. If the extension were to cost £100k then we would be able to fund £50k ourselves in savings and borrow another £50k from parents. The plan would then be to remortgage the house at its new value once the work was done (say £600k) to pay the parents back the £50k borrowed from them.

We put down a 25% deposit when we bought the house and are paying interest only (so that we can save a decent amount of money monthly for the extension). We did not stretch ourselves to buy the house.

We live in an area where house prices have continued to rise.

I know that there are lots of variables with this (contingency for the extension, the value of the house when the extension is complete) not to mention the hideous prospect of having a massive building project done. I just would like to know if it a vaguely feasible plan and how it would work when we came to remortgage.

Hope this makes sense!! I would be so grateful for anyone's advice!

Personally, I would leave the extension until I had saved all the money for it - 100k sounds a lot!!!

Yes it's feasible, but as you say it's subject to a lot of variables. Plus if you want to stay on interest only repayments when you remortgage you will still need at least 25% equity in the property with most lenders. Agree that if at all possible you need to either save up the full amount, or ensure your parents know it may not be possible to remortgage to repay them without repaying some of the capital outstanding first.