Levelling a floor

[PartialToACupOfMilo]

We're thinking about putting a wooden floor down in the dining room, but it's pretty uneven and I think it will need levelling first. Is this a job you can diy or is it better to get someone in? And approx how much do you think it would cost?

We need to get the carpet up and have a look at the floor properly of course - this is just first thoughts. But I know there are quarry tiles down currently and it's a Victorian terrace if that makes any difference. There is a step down from that room to the hallway and French doors to the garden - will these make it complicated? I'm having visions of not-yet-set levelling stuff dripping down the step or it going above the level of the French doors and ruining them too - this won't happen, will it?!

tia :)

The ones we've seen (not taken up whole carpet yet) are in very poor condition so not really anything you'd like on show and the carpet we currently have down has visible indentations around a doorway, the fireplace etc, so unless you can take them up and pass them on then levelling and 'ruining' them is the way forward. It's most important for us to have a room that works for our family.