Loft ceiling binder: cut and attach to new joists?

[Dr Rock]

Hi all!
Boy am I glad I've found this site I've had a search around but can't seem to find the definitive answer to the immediate problem, which is:

I have an Edwardian mid terrace house, that has a room in the attic. Been there 100 years, floorboards, dormer window already there. It was plastered but the plaster was falling down so I have removed all of it, with a view to insulating the underside of the roof and making more use of the space. 2/3 the way across the room there is a partition wall, that is not structural (more than one builder and planner has confirmed this) so I want to remove these upright wood sections and have the whole of the top of the house to use as a music room. I am either going to have a permanent wooden ladder as access or a spacesaver staircase.

Problem is, the joists are 5x2's under the floorboards, and only 3x2 for the remaining 11ft. There is a 5x2 ceiling binder that runs at an angle across these 3x2's and I want to put new 5x2s (or maybe 5x3's) down parallel to the smaller joists so I can floorboard the rest of the space. These new joists will rest on structural brick walls at both ends.

The binder is in the way Can I cut it, put the 5x2's down and then bolt/nail/secure the binder to the new joists, as well as putting cross pieces between the new joists, to maybe make a lattice/crosshatch pattern?

Many thanks for your help, more posts will undoubtedly follow!

Cheers,

Fraser

 

[masona]

I am either going to have a permanent wooden ladder as access or a spacesaver staircase.

I'm afraid you will need building permission for this and the correct size joists etc, best to pop down to your local BCO for their free advice, they are normally very helpful. I have seen many cheap loft conversion in dangerous condition.

 

[Dr Rock]

Thanks for the reply, but it's not a loft conversion though: the room is already there and had a staircase in, but 20 odd years ago the staircase was taken out. All I am doing is putting better access in, in a safer location than having a metal ladder at the top of the main staircase And if 5x2's have been up there for 100 years and are absolutely fine, spanning a greater distace than I want to do, then I don't see what is wrong with putting extra ones in now. If I do put taller joists in the new area, then that means the floor will be on 2 levels, which is daft

 

[masona]

Without seeing it I can't say, 5"x2" is not really strong enough unless it's well supported on bearing walls and depending on the span length.

The reason for building regs are for safely such as fire escape if fire break out below.

 

[Dr Rock]

I know why the regs are there, and fair enough for a new build, but if the whole area had 5x2's from the beginning then there wouldn't be a problem. The span is 11ft max and the joists will be supported by load bearing masonry walls at either end, so I don't see a problem with support.

As for fire I want to replace the dormer window with one that opens so I can have a fire escape ladder out onto the bay window downstairs, so having a fire escape is covered.