Old house (1725) , rubblestone wall, huge victorian timbers down centre of downstairs room ceiling. I'm looking up at ceiling (woodfibre ceiling now removed)
Joists span between wall and central timber: clear span 2.29m
joists (victorian pine I think) ends have rotted out, I found previous 'repair by sistering' with new timber ends supported on lime plaster.
It's a mess, only 2 joists long or strong enough for span from central timber to stone wall, lots of worm and spongy wood, double and triple sistering with odd bits of this and that. (Except that there are 2 newer 7" by 2" joists well supported and in good condition.)
So, new joists, and looking to decouple floor above from ceiling, so thinking separate ceiling and floor joists, or resilient bars, to soundproof.
I'd rather not make new slots in the wall for joist ends so that means joist centres at 600mm
looking at: http://www.dfpni.gov.uk/d.pdf page 12, and at //www.diynot.com/forums/viewtopic.php?t=259050&start=15 RonnyRaygun page 2 of thread
It looks like:
Floor joist loads without ceiling: (kN/sq metre)
Boards 0.15
Joists 0.15
Total dead load therefore 0.3
clear span is 2.29m
Therefore (looking at table) at C16 I could use 38mm by 145mm joists (6" by 1.5")
So floor joists 7" by 2" would be more than adequate?
And if I decided to use resilient bars, instead of separate ceiling joists, I would be adding the dead load of the ceiling , plus sound/thermal insulation fleece eg: http://www.thermafleece.com/product/thermafleece-ultrawool
ceiling: 0.1 (kN/sq m)
ultrawool at 50mm weighs 3.1kg/m sq = 0.31 kN/m sq
so the total load would be increased by 0.41
= 0.7
so I could still use 38 by 145 (6" by 1.5")
So combined floor and ceiling joist of 7" by 2" would still be more than adequate?
Any thoughts?
Many thanks,
Stephen
Joists span between wall and central timber: clear span 2.29m
joists (victorian pine I think) ends have rotted out, I found previous 'repair by sistering' with new timber ends supported on lime plaster.
It's a mess, only 2 joists long or strong enough for span from central timber to stone wall, lots of worm and spongy wood, double and triple sistering with odd bits of this and that. (Except that there are 2 newer 7" by 2" joists well supported and in good condition.)
So, new joists, and looking to decouple floor above from ceiling, so thinking separate ceiling and floor joists, or resilient bars, to soundproof.
I'd rather not make new slots in the wall for joist ends so that means joist centres at 600mm
looking at: http://www.dfpni.gov.uk/d.pdf page 12, and at //www.diynot.com/forums/viewtopic.php?t=259050&start=15 RonnyRaygun page 2 of thread
It looks like:
Floor joist loads without ceiling: (kN/sq metre)
Boards 0.15
Joists 0.15
Total dead load therefore 0.3
clear span is 2.29m
Therefore (looking at table) at C16 I could use 38mm by 145mm joists (6" by 1.5")
So floor joists 7" by 2" would be more than adequate?
And if I decided to use resilient bars, instead of separate ceiling joists, I would be adding the dead load of the ceiling , plus sound/thermal insulation fleece eg: http://www.thermafleece.com/product/thermafleece-ultrawool
ceiling: 0.1 (kN/sq m)
ultrawool at 50mm weighs 3.1kg/m sq = 0.31 kN/m sq
so the total load would be increased by 0.41
= 0.7
so I could still use 38 by 145 (6" by 1.5")
So combined floor and ceiling joist of 7" by 2" would still be more than adequate?
Any thoughts?
Many thanks,
Stephen
