Borrowing money for a extension - help?

uropachild

After much milling over my husband and i have decided to stay put and extend our house. We have builder that we're going with, so now we just need to sort out the money.

The house is worth about £130-140,000 and our remaining mortgage is £65,000 with a 21 year term left. The extension will cost us £30,000 and we will need to borrow £26,000 of that.

We're fortunate that we're on the Halifax SVR, which is 3.5% at the moment. Obviously that means that we really don't want to move to another mortgage because we wouldn't get no where near as good a rate as that. So, how would we borrow this extra money? I take it the Halifax won't just let us have another £26,000 on the SVR?

Thanks!

Oh, and while i'm here i was wondering if anyone knew roughly how much value the extension will add to our home? We're staying put for a fair few years now we've decided to do this, but it would be nice to know. Here are some details:

1970's semi detached house with 3 bedrooms and bathroom to first floor. Ground floor has a nice sized entrance hall, through lounge/diner and a kitchen. When we extend we're taking it 3m back across the whole rear of the house (5.6m. The other length of the house is 8.6m from front to back, if that matters). It will be single story with a sloping roof and two velux windows. The whole of the extension will be a kitchen diner. The old kitchen will become a study with a shower room off that. What is now the dining part of the lounge diner will be a kids sort of play room, but could be the proper dining room. The lounge will be separated with double doors going through into the kids play bit / formal dining.

I know it's hard to picture from just that explanation, but hope you can make some sense of it!

TMSL

HalifX will offer you a further advance (extra boorrowing) at very decent rates and with minimum fuss