Knocking 2 bedrooms into 1??

[littlemissblue]

We are thinking about offering on a house but we have 3 children and currently my 2 girls share which works well for us, this house is 4 bed but the 3rd bedroom is just too small for them to share so we are thinking about knocking rooms 3 and 4 into one. (And eventually adding a loft extension to make it 4 bed again)

How difficult would be this be? And costly? Don't know if it is a supporting wall or not.

Any advice appreciated!

(Pic attached)

If the wall is timber frame and plasterboard it probably isn't load bearing. In which case the cost is a low hundreds and the longest most disruptive and expensive part is re-decorating afterwards.

If the wall is brick or block it probably is load bearing. In which case the cost is a high hundreds to low thousands as a steel beam must be put in.
That is messy and longer. A short section of the original wall probably would need to be retained to carry the beam.