ceiling joist timbers
Discussion
Davi said:
Normal domestic indeed, C16 or C24 grade. Think 4x2 will be fine just wanted to check 
C24 Stress in bending unfactored is 7.5Nmm2Z for 100 * 50 is = 83333mm3
Mnt capacity = 83333 * 7.5 / 10^-6 = 0.625kNm.
Assume house loading is 5kN/m2 mnt is 5*1.4^2 / 8 = 1.225 kNm. Therefore if you space them at 0.5m centres these will be ok, guessing they are more like 350 centres so easily enough.
What length of bearing?
spacing is 350 indeed, cheers
Now here's another question for you...
Pole plates - is there any reason that they have to sit directly over the inner skin? just realised the bricky has made a small error, making the inner skin about 150mm too low. I can up the joist dims to say 150x47 to raise the pole plate a couple of inches but it would still leave me 100mm short. Moving the pole plate out on the joists by 100mm or so toward the outer skin would get around it quickly and simply!
Now here's another question for you...
Pole plates - is there any reason that they have to sit directly over the inner skin? just realised the bricky has made a small error, making the inner skin about 150mm too low. I can up the joist dims to say 150x47 to raise the pole plate a couple of inches but it would still leave me 100mm short. Moving the pole plate out on the joists by 100mm or so toward the outer skin would get around it quickly and simply!
Davi said:
spacing is 350 indeed, cheers
Now here's another question for you...
Pole plates - is there any reason that they have to sit directly over the inner skin? just realised the bricky has made a small error, making the inner skin about 150mm too low. I can up the joist dims to say 150x47 to raise the pole plate a couple of inches but it would still leave me 100mm short. Moving the pole plate out on the joists by 100mm or so toward the outer skin would get around it quickly and simply!
Sole plate mate not pole plate.Now here's another question for you...
Pole plates - is there any reason that they have to sit directly over the inner skin? just realised the bricky has made a small error, making the inner skin about 150mm too low. I can up the joist dims to say 150x47 to raise the pole plate a couple of inches but it would still leave me 100mm short. Moving the pole plate out on the joists by 100mm or so toward the outer skin would get around it quickly and simply!
I assume the plate is taking the roof?
And from what you are saying the internal block work is too low to take the plate, so needs building up some how?
Now from you explanasion (sp) the blockwork is a good 10" low???
So you want to put 6x2s in sitting on the internal blockwork, then have them too long so you can fit the plate over the cavity?
Am i correct or getting the wrong end of the stick?
I have that detail on my 1936 house here , i dont like it , the pole plate has started to twist under spread from the rafters .
I would just put bigger ceiling joists in , make sure you truss clip the plate to the c/j too .
For good measure i would put some solid blocking between the ceiling joists under the pole plate
I would just put bigger ceiling joists in , make sure you truss clip the plate to the c/j too .
For good measure i would put some solid blocking between the ceiling joists under the pole plate
Autonotiv said:
Sole plate mate not pole plate.
Wall plate not sole plate, a sole plate is the bottom part of a stud wall, wall plate and pole plates are what trusses, ceiling joists sit on. A pole plate usually occurs when the trusses are in two parts and have what's called a top hat on them which is the triangular part at the very top,(the pole plate runs on top of the lower trusses so the top hats can be fixed) usually only when the overall height is 4m or above.ie. they'd have difficulty in transporting the whole trusses to site, so they're made in two parts.
Regarding having the wall plate on the outside, this is very rarely done, plates always sit on the internal blockwork mainly to stop them rotting or getting damp as on the outside brickwork they would be open to the weather, plus you will have to nail the wall plate straps to them that hang vertically down the wall and fix to the blockwork.
TvrJohn said:
Can i ask if this is correct
New floor joists in a loft 200 x 75 set at 600 pitch, the pitch seems very wide as i intend to floor out in 22 t & g chip board panels.
What do you think, correct ?
New floor joists in a loft 200 x 75 set at 600 pitch, the pitch seems very wide as i intend to floor out in 22 t & g chip board panels.
What do you think, correct ?
8x3 joist with 600mm centres ? You can always nog along the joints with 4x2 if you like,plus use pleanty of glue in the t&g to avoid any squeaking .Promised Land said:
A pole plate usually occurs when the trusses are in two parts and have what's called a top hat on them which is the triangular part at the very top,(the pole plate runs on top of the lower trusses so the top hats can be fixed) usually only when the overall height is 4m or above.
Its also known originally , that a pole plate sits on top of the ceiling joists to receive the rafter feet , rather than sitting on top of the wall.Edited by Busamav on Saturday 22 November 14:18
Promised Land said:
Autonotiv said:
Sole plate mate not pole plate.
Wall plate .Can any one post a picture of a pole plate? As far as i'm aware iv'e never seen one (only the apprentice)
D14 AYS said:
TvrJohn said:
Can i ask if this is correct
New floor joists in a loft 200 x 75 set at 600 pitch, the pitch seems very wide as i intend to floor out in 22 t & g chip board panels.
What do you think, correct ?
New floor joists in a loft 200 x 75 set at 600 pitch, the pitch seems very wide as i intend to floor out in 22 t & g chip board panels.
What do you think, correct ?
8x3 joist with 600mm centres ? You can always nog along the joints with 4x2 if you like,plus use pleanty of glue in the t&g to avoid any squeaking .Do you do loft conversions if so can i pick your brains
Sorry thread hijack over
V12Les said:
600 is to wide even with 22mm boards. 400 centres is the norm, and make sure you glue n screw the boards down, you'll be cursing forever if you dont. One more thing, make sure the timber is dry.
600mm is quite wide but without all the material properties I can't check deflection which would probably be the main criteria. Autonotiv said:
Thats what i ment, i was siting here thinking sole plate, i'm sure thats not correct, sure its not called that, lol.
Can any one post a picture of a pole plate? As far as i'm aware iv'e never seen one (only the apprentice)
It's basically the same as a wall plate but sits ontop of ceiling joists or trusses in the same line as the wall plate, a common occurance is when you do lean too roofs, the ceiling rafters go from the wall plate to the bearer on the wall, the mono roof rafters come down to the plate as a normal roof but sometimes the plate is too low, so you put a pole plate through on top of the ceiling rafters, to birds mouth the rafters over. It's usuauuly set back from the wall plate 100-200mm, if you're just looking at a roof someone else has done you probably wouldn't regonise it.Can any one post a picture of a pole plate? As far as i'm aware iv'e never seen one (only the apprentice)
Very common on hips, a pole plate 45 degress to the two wall plates to get a birds mouth.
Not too scale, just an example.
Edited by Promised Land on Saturday 22 November 17:36
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