I am looking into buying a property where the loft has been converted but only velux windows installed. Planning permission is not a problem as there are a lot of properties in the same street and area where this has been done. I am just looking for an approx cost of getting one fitted, would be looking for quite big one, maybe 10 foot wide. Any help would be appreciated.
Yes indeed. You need to be very clear whether this conversion has been done with Building Regulations approval, or not. Otherwise it is not classified as habitable space and the seller of the property cannot claim it as a bedroom. The 'killer' costs are ensuring the right amount of insulation was installed behind the plasterboard (it will have needed at least 150mm of Celotex - NOT fibreglass - possibly more), and whether the access arrangements meet fire regulations. Assuming this is the 2nd storey, the fllor level will more than 4.5m off the ground (unless it is a tiny cottage) and this triggers the needs for ALL the doors off habitable rooms that lead onto the route to the ground-floor to be 30-minute fire doors. That includes the room where the loft conversion is.
This work will cost a lot more than £2000 if the extension structure has not been built to this spec.
Regarding the dormer itself, this sounds about right though only if it can be fitted without erecting scaffolding on the outside (i.e. assuming it can be done from the inside)
Don't assume that, just because other properties have dormers, its a given that you can have them too. A lot of them will have been done under permitted development rights, which changed in October 2008, and some dormers now need planning permission. Depending on the size and design, your plans may not be welcomed by the Council.