Roof Replacement: Wipe out savings, take out a loan or a bit of both?

We've recently found out we need a new roof on the house we bought two years ago (knew there was a catch for it being at least £20,000 cheaper than the other houses that have sold on the street!) We've had a few quotes and thankfully, the most reputable contractor came with the lowest price. The roof replacement will cost just over £11,000.

I've got just over £10,000 in an ISA and my wife has around £8,000. Since moving I've said that that cash is for "house stuff" and replacing the roof certainly falls under that.

I'm inclined to wipe out the £10k in my ISA and my wife is happy to top it up, however, this would take our savings for a rainy day down to £7,000. We're expecting our first child in February and adding to a maternity pot, but also want to do a few more bits to the house before the baby arrives.

I've always been worried about debt and hate the thought of owing anyone else (other than the mortgage provider and car dealership) any cash, but wondering if taking out a loan for half the amount and repaying over 2 years would be a better option?

Really stuck as to what would be the best option. Any insight would be appreciated! Diolch.