Mortgage - Joint with parents?

[schmunk]

Hello All

I'm considering buying a house with my parents (don't laugh). Rough figures:

They will initially buy the house alone - ca. £1M, with a £200k mortgage.

We want to spent ca. £500k on extending to roughly double in size and create effectively two separate wings (so we could move in and have privacy!). To do this we would add £150k in equity and £350k of mortgage.

Being relatively elderly, my parents can only have a mortgage for the next 8 years, but would pay off their £200k in that time. I cannot currently borrow more than the £350k, or pay more than the repayments on that amount.

Any ideas on how we could structure this to allow both parts of the proposed mortgage to exist now as a first charge at relatively low rates? Could we jointly borrow £550k, for 8 years, with interest only on ca. £350k (so that we don't have to pay off our £350k at an accelerated rate)? Has anyone done anything similar?

[schmunk]

Thanks for the suggestion, but how would either of those help with my mortgage query?

[schmunk]

Thank you both for the replies - it looks like it's a goer; just need to see whether our offer's accepted now.