Ok.. our mortgage is on the lowest baseline rate so doesn't cost us much in the grand scheme of things. We would like to borrow about £15,000 extra. My question is, if we borrow more is this remortgaging or can we take out another mortgage on this amount? Only ask this as i don't want to change the rate the other larger mortgage is on...hope this makes sense! The new amount we would fix over 5 years over a 20-25 period. Just playing around with figures as may try and do an extension on the house. any ideas?