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just so any readers know the rsj is a uc 203/203/60 and seven mts over a six mt opening cheers rob

Hi all had some great help of tony 1851 and jeds when i ask rsj help so rsj size is sorted have a lean to conservatory, with a tile roof running at 18 deg question about rafters to rs j now trying to save a bit of high can i bolt a timber beam to the web of the rsj and fit the rafters...

that's very true, and thanks to all you guys for helping me, clearly the SE i used went way over the top on his vaules so the beams were too much!!!! anyway all sorted and thanks again

hi well just a safty margin. working on figures of yours and mine tiles 0.1 batton 0.01 felt 0.01 raf 0.2 cel 0.15 mine say 0.35 which looks high 0.47 if i stick with 0.75 LL mine 0.6 would give me 1.22 total so your right moving to 1.35 is a safety margin

hi guys just a double check if i use LL 0.75 DL 1 useing a uc 254/254/73, x-x vaule of 11407 i get a deflection of 3.45mm am i right ?

well thanks guys looks like i need to get a set of SE calculations look a bit over the top the set i have using a LL 0.75 and a DL 0.47 with what i have but take it up to 0.85 instead of the 1.27 he used

ah forgot about that divide by two plus its light weight tiles only 9.47kg sq mt think thats 0.1 kn

well looking at some SE calculations its done by calculation and thats where the prob is vaules a high 1.27 DL AND 0.6 LL

are you using 0.0063*1.6*6^3/2348?

from his calculations, just testing i am reading the formula right rob

hi am i being thick but using the formula just making sure i read it right ? for uc 203/203/52 0.0063*1.87*6^3/5259 im getting 0.0004838745 must be doing something wrong ? steel tables say 5259 but what about area of roof? ie 24 sq mts come in to this ?

thought so, when i looked at the values did tell him at the time what i was using, but now he passed away

they weigh 630grams and approx 13 to the sq mt

ah but i found some called envirotile interlocking roof tile and they are 9,47 kg sq mt, thanks for all your help

yes your right on the plasterboard 0.35 is high but the tiles are 9,47kg sq mt his calculation is 0.7 how much does that improve the deflection?

well tile/slate is 9,47 kg sq mt then batton 0.01 kn/sm felt 0.01 kn/sm rafters 0.2 kn/sm ceiling 0.35 kn/sm

sorry 254/254/73 uc

would i get near the 4mm if i went to a 154/254/73 uc?

sorry being thick yes see its 6mm

thanks for that looking at the calculations i have he say deflection is 4mm and need to stay under 8mm, a pair of 203/133/30 would give me 7.5mm deflection which is too close for a 6mt span what deflection would i expect with a 203/203/52 ?