Timber Joyce 8 by 2 C24

[Patsy786]

Hi,

I intend to do a dormer conversion intent to use 202 by 202 46kg per meter. The spans runs for 5.5meters with no spine wall support. i intend to make the floor out of 8by 2 c24. the span to long in length? Do I need to break this span by either creating a spine partion or supporting RSJ? Alternatively break the span of 5.5 m and add another steel and then continue the run from the new steel?

Any advice would be greatly appreciated..I have a height restriction so really don't want to use timbers bigger than 8 inches.

 

[noseall]

200mm x 47mm won't even touch a 5.5m span even at 400mm c/c.

You need a coupla more inches of depth.

 

[Patsy786]

Sorry not sure what you mean? Do you think it's sufficient?

 

[noseall]

Do you think it's sufficient?

Err, no, I don't.

 

[Patsy786]

So what do you actually mean?

 

[tony1851]

200mm x 47mm won't even touch a 5.5m span even at 400mm c/c.

You need a coupla more inches of depth.

How about if he reduced the spacing - maybe @ 300??? Just wondering

Or double them up to make 8x4s?

 

[DevilDamo]

According to the TRADA span tables, you would need floor joists of at least 63 x 220mm at 400 c/c assuming a dead load of not more than 0.25 kN/sq.m, which will span 5.61m.

However, surely you would already have a structural engineer on board who designed the steels, so why not get them to help with the floor? After all, Building Control would request structural engineers' details/calculations anyway.

 

[jeds]

Use "I" joists instead of timber joists. Spans up 7m+ achievable. You will need a designer though.