Can I borrow money for renovations when moving house, by taking out new mortgage?

jasatmsf

Can anyone explain if the following is possible: I want to move house, and the house I am considering buying may need some work (minor renovations, small extension).
I am selling my existing house, which has a mortgage.  My plan is to pay off the existing mortgage with the money from sale of my current house, and take a new mortgage out on the new property.  The end game is to have money for renovations in my bank account ready for building works. 
Example numbers: 
Sell price: £775,000
Buy price: £700,000
Outstanding mortgage: £270,000

Mortgage amount required to buy new house: £195,000

....I think I'll need a renovation budget of: £100,000
therefore I would like my new mortgage to be: £295,000 

What happens?  Do I approach my existing lender with this plan?  On completion day does all the above (sale/purchase) happen and I end up with the renovation budget in my nominated bank account?
I've tried talking with my bank but they're a bit busy at the moment, and it's a bit of a wait to speak to the mortgage advisors! Sorry if this is an obvious question, I've not done this before.  Last time I moved house it was a straight forward "I want to borrow more" conversation, no money left over, everything went on the mortgage. 

NB: I am assuming no fees/stamp duty etc in the above figures to keep things easy for illustration purposes.  I haven't forgotten about them. 
Also, assume no early redemption fees for current mortgage.  I will be paying the SVR by the time this sale goes through. 

GixerKate

So you want to keep some of the equity from selling your current property back to do renovations to the new property?  My limited understanding is that yes, you define how much of the equity you want to use as a deposit and I think the remainder stays in your account.  I could be wrong though.

foxy-stoat

All seems ok, as long as you meet the lenders affordability calculator for the amount of mortgage you need.  You will get your cash equity from the solicitor after all the fees are paid.

dimbo61

Yes this is possible provided you earn enough for the bigger mortgage and have good credit score, no CCJ,s or defaults.
Consider an offset mortgage so you can keep the extra funds to pay for the renovation works in the Offset account.
As your builder asks for payments you will have the monies sat in the offset to pay them.

jasatmsf

Thank you all for your comments, that is reassuring.  Good idea regarding the offset account too, although I am put off by the rates as they seem comparatively high.  I'm leaning towards fixed rate for 5 years to give me stability, so need to consider how the cost of borrowing would be over that time period with regards the offset - after all, the plan would be to spend the offset amount.