L
Leofric
The timber and steel joists are Easi-joist open web system by Wolf Systems. They allow services to pass through as big as 110mm soil pipes. No need for steel beams . Just a thought.
Span tables for deep joists
- Thread starter garyo
- Start date
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I'm starting to like the look of this. In the garage at the bottom of the drawing the longest span is only 1.8M so I could get away with 150mm @ 400c/c as Tony says. In the room at the top the spans are wider with a single steel.
I think the way to go might be to go to a single steel in the garage too and then standardise the joist depth to 195mm @ 400c/c across the whole extension, and then the joist depth will also match my roof rafters which will add convenience.
I think the way to go might be to go to a single steel in the garage too and then standardise the joist depth to 195mm @ 400c/c across the whole extension, and then the joist depth will also match my roof rafters which will add convenience.
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L
Leofric
Can't be sure but it looks as though one of those proposed steel beams might be bearing on to a lintel over an opening !
I wonder how the cost of traditional timber joists and 3 new steel beams would compare with doing it in the Easi-joist system but I don't suppose we will find out.
Regards
I wonder how the cost of traditional timber joists and 3 new steel beams would compare with doing it in the Easi-joist system but I don't suppose we will find out.
Regards
Sorry that's just the positioning of my section plane that's just caught a bit of the upstairs layout, so no issue.
I'll take a look but the last time I asked for a quote from JJ it didn't add up for me given the weather exposure risk and the general nervousness you get using a non standard system.
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L
Leofric
As in Post 7 and as Woody says the double trimmers would be the usual way of doing it. I should have posted this earlier but just realised I have a copy of the old Approved Document A , and according to table 1 for class SC3 timber joists at 400mm crs (dead load more than 0.25 but not more than
0.50 kN/m2 ) you can span 4.91m with 220 x 63mm size joists. So I think that answers your original query and you wouldn't need to use any steelwork.
0.50 kN/m2 ) you can span 4.91m with 220 x 63mm size joists. So I think that answers your original query and you wouldn't need to use any steelwork.
Is there a point when the trim span is too much? At what point do sistered trimmers need to be tripled?
We used Posi-Joists to span our current 7.6m extension, coming out at a mere 450mm deep!
L
Leofric
'Bolt trimmer using 51mm diameter double-sided round toothed plate connectors and M12, grade 4.6 bolts at 600mm centres.' - double joists as trimmers should be bolted together. There are Building Control guidance tables for trimmer joists/beams and trimming joists. Depends if trimmers are also supporting partitions above but usually joists are tripled when they are 'trimming joists' supporting a 'trimmer joist/beam ' in my experience ,but it depends on spans and loadings.
Double joists as trimmer should be ok across your 2872 opening but I can't prove that.
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