Ceiling onto loft floor joists?

[Skiny]

Is it acceptable to building regulations, to fix a ceiling , directly onto loft floor joists? I have had new joists fitted (8x2), for a future loft conversion, as I'm currently renovating the rest of the house and had the ceilings down.

I've heard that the loft floor should be independent to the first floor ceiling, but is there any specific reason for this? I assume it's because regular ceiling joists would never normally be strong enough, but in my case of having stronger ones in place, would it be alright?

 

[oldbutnotdead]

Separating ceiling from floor reduces noise- important in flats, not so critical in family homes. 8 x 2 will be fine for 4m span at 400 centres, older places having loft conversions would probably have skinny little 3 x 2s as the ceiling joists- you really wouldn't want to put a floor on them.

 

[Skiny]

Thanks for the reply.

Yea, the old skinny ones are what the ceiling used to be attached to, but they're very warped out of shape. Obviously I'd rather not fix my new ceiling onto that, especially when I have the brand new 8x2s in place.

Would it be against some regulation if I were to do that, considering I want to have a loft conversion done next year? It's not a flat, but my own home.

 

[oldbutnotdead]

Pretty certain you'll be OK as its a renovation not a new build. You could give your local building control a ring and check with them- keep it hypothetical though

 

[tony1851]

As o.b.n.d, you would be OK to fix a new ceiling to the new joists. But you would need to make the new floor 30 mins fire-resistant if you are getting rid of the old ceiling joists. This would entail using Fireline board rather than normal plasterboard.

 

[Skiny]

Great, thanks for the answers

Looks like double boarding with the Fireline board you recommend would do the trick for the 30 min resistance.

Are there any requirements for the loft floor insulation? I guess not if it's going to be a habitable room above?

 

[oldbutnotdead]

Assuming you've got a cold roof (ie no insulation under or between the rafters etc yet) then you'll want something in there for the winter. If you're not putting flooring in the loft yet then you can pull the insulation out when you do the loft conversion next year (or you can leave it in, might reduce sound travel from loft downwards but might also increase how much heat you have to put into the loft rooms in the winter to keep them warm)