Joist Span Table Question

[Charlie Kilo]

Hi,

I'm new to this so bear with me..

Using the table in the link below I'm going to need to use 47x200 of C16 or 38x195 of C24 because I need to span 3m, take a load of between 0.5 and 1.25kN/msq and my joists are going to be 600mm apart.

Do my verticals need to be the same dimensions or can I use (for example) 47x97 (C16) or 38x97 (C24) respectively?

http://nhbccampaigns.co.uk/landingpages/techzone/previous_versions/2010/Part6/section4/appendix.htm

Thanks,

Charlie K

 

[bobasd]

Charlie k,
what are you proposing to do?

joists are fine.
if by "verticals" you mean studs for framing something then yes your OK

 

[Deleted member 174758]

Think I'd prefer to joist out at 400mm or 16in centres (depending on what the floor material was to be)

 

[Charlie Kilo]

I’m looking to build garage roof storage space and maybe a little office area across a 6x7m (6m width) double garage by placing joists parallel and between the existing 600mm spaced truss chords.

As the joists need to be deeper (either 200 or 195) than the horizontal chords of the truss currently are (I think closer to 150) I’ll be able to mount plasterboard on the underside of the joists and chipboard on the upper side, leaving the truss system totally alone. I only need to chipboard the section of floor between the two longer webs of the truss, so 2m or so.

Or I could mount the joists level with the underside of the chords as I understand the chords can cope with the load of the plasterboard. Can’t see a difference either way there.

There would be three stud walls, one at each side wall and one down the centre, all perpendicular to the chords and joists, so 2x3m spans for the joists, I’d use 6m timber. And it’s the dimensions of those studs, the ones that will support the joists, that I’m asking about. It’s a brand new, new build garage, floor is concrete. Seems a bit of an overkill just to have 14msq up there but I need the space and need to partition the garage down it’s length in any case.

Some might say just to partition up against the chords and that would be enough to support some floor, a desk / computer / person up there, but I’d rather do it properly..

I haven’t even bought the place yet and may not do so if the world continues to spiral as it seems to be, but just thinking ahead!

What are people’s thought on plasterboarding the insides of the longer webs of the truss, creating a triangular type ‘room’ up there? I want to avoid touching the roof system if possible but is that a goer or not?

Thanks

 

[tony1851]

75 x 50 C16 studs @ 400 centres, boarded with either plasterboard or 11 OSB, would be perfectly OK for that situation.