Ceiling joists not secured

[RrogerD]

I've stripped the plasterboard from the flat-roofed ceiling of the downstairs kitchen and bathroom. The last joist, adjacent to the partition walls, in both rooms is not secured down. Obvs this doesn't seem right to me.

Am I correct in the last joust should sit about 2 inches from the adjacent parallel wall?

In other words, I don't screw this last joist to the wall but instead need to screw it down at it's end presumably using straps of some sort?

 

[johnny2007]

Sometimes you find them bolted to the wall.
Not unusual.

 

[RrogerD]

Sometimes you find them bolted to the wall.
Not unusual.

What's the reason for leaving the gap? Presumably to avoid condensation damp from the wall?

 

[johnny2007]

In theory, yes, but in reality if the wall is constructed properly it won't make any difference.
In fact, old council properties were all done like that.
I remember the masters saying that it prevents bouncing of the floor.
That's true, in fact if you think about the floor joists connected by noggings, once bolted to the walls keep it a lot more rigid.

 

[RrogerD]

In theory, yes, but in reality if the wall is constructed properly it won't make any difference.
In fact, old council properties were all done like that.
I remember the masters saying that it prevents bouncing of the floor.
That's true, in fact if you think about the floor joists connected by noggings, once bolted to the walls keep it a lot more rigid.

Thanks. Just seen some straps in Screwfix. Will probably go for these, used upside down.
https://www.screwfix.com/p/sabrefix-standard-jiffy-hanger-47-x-277mm-10-pack/25392

 

[RrogerD]

I've just had another look and I think the reason that they may not have screwed to the adjacent wall is that I think, it is built from PFA blocks. It's only a non-loadbearing internal partition wall. Using the straps may be a possibility but it looks as though it will be difficult getting the strap up and over the joist and down the other side, adjacent to the wall.

How does one affix to cinder blocks?

 

[johnny2007]

?