New floor over old

[Rudidudie]

Hello. I have an old farmhouse that dates back to the 1650s. The roof/loft space has only ever been used for storage, but I need to convert this space into bedrooms. On account of the age and nature of the building, the floor of the loft space is extremely uneven. It is not possible to rip up the existing floor and re-set the joists as the finished & decorated ceilings of the ground floor rooms all ‘hang’ on the existing structure.

So…. I am thinking of laying out a new timber frame over the existing, uneven loft floor, chocked up as necessary, and then screwing particle board down onto this framework to create a new, level surface.

The existing structure is made up of five massive oak beams that run from one side of the property to the other, and oak joists which are set onto these beams, running front-to-back of the property (hope this makes sense).

Should the new framing run in the same direction as the existing joists, or across them at 90 degrees?

Any pointers, suggestions or warnings would be appreciated. Many thanks

 

[RedHerring2]

I'm only a DIYer but I would suggest it depends on the size of the new joists that you intend to use.
If of sufficient depth you can run them between the five oak beams, thereby not relying on the smaller oak joists. Use timber tables to determine the depth of joist required.
If however you were planning on using minimal depth of joists, then run them at right angles to the oak joists, i.e. in the same direction as the five oak beams.

 

[mointainwalker]

Particle board. Why particularly ? What will the finshed floor be ?

 

[Rudidudie]

Thanks, folks.

Mountainwalker: you asked why particle board? I'm planning to carpet the rooms I'm creating (master bed and kiddies' bed) as I'd like a warmer/softer/quieter floor than elsewhere in the house.

I see you're in France too, so you'll understand me if I say the floor itself will be 'dalle agglo' or 'panneau osb'. Given your query, do you have any comments/observations on this idea (positive or negative) - cheers!

 

[mointainwalker]

Particle board is the lowest quality flooring material : doesn't take screws well, crumbles if gets wet and if not very well fixed, squeaks like hell.

Unsure how much better OSB is, maybe one of the real builders will weigh in with advice.