Home extension/ raising cash

[TAP100]

I'm in the process of buying a small property and I hope to buy it outright. Can any body tell me what is the best way to raise the cash for an extension and alterations ( it's in need of a fair amount of work). This is all new to me and I have no idea what my options are.
Can I get a mortgage as such for an extension or is my only option a loan?
I need to spread the cost and I intend to stay in this property for a long time.

Not sure I understand.. You mean you have the money to buy the house in cash, but not for the extension?

As I understand it, mortgage lenders are interested in the loan-to-value ratio. So, in a simple case, if you fully owned a property worth £100k, and the lender offered 90% mortgages! you could borrow £90k. If you already had a mortgage of £80k, you could borrow a further £10k. Don't forget, though, that there will be fees associated with taking out the mortgage, and that the higher the loan-to-value ratio, the worse the interest rates become.

Purchase the property with a mortgage to allow you funds for the extension and alterations. We did exactly this a few years ago.

Thank you very much for the advice.
I have put an offer in for the house and I was unsure whether to buy outright or whether to do as advised and and get a mortgage. This is my first foray into Mumsnet and I appreciate those of you who have replied.
Thanks again.