Joist hanging

[FRAN1870]

hi all,

Just installing the main double joists for my loft conversion and the design specs them to sit 150 higher than the floor because two of them are supported by a steel ( See attached layout )

Anyway I've obviously got to sling the cross joists between the rafters but need to get them as low at possible.

The joist hangers I've bought look too short now ( live n learn ) so can you recommended the correct hanger please ? Or maybe a solution ?

I understand that I can only notch the joist ends to drop it down by 1inch ?

Is that correct ?

 

[^woody^]

Take the hangers back and buy the correct ones

 

[FRAN1870]

Take the hangers back and buy the correct ones

Thanks Woody that's a solution for sure but I can't return them as they were bought from a selling page on Facebook.

No biggy as it was only £20 for 50 so I can Ebay them.

In the absence of experience then I'm a bit unsure which ones to get ? The regs say "all available nail holes" but clearly the holes that hang below the joists I won't be able to nail to fresh air

Sorry if it's an SFQ.. I've built a few garden decks but I've never used hangers before.

Appreciate any guidance

 

[theprinceofdarkness]

Rafter hold the roof up. Picture 1, do you want your joists to sit lower then where you are holding your joist hanger? This means that your double joist will sit higher then the floor (under the walls, perhaps). If you level the joists to the top of the double joists will you still get enough headroom. Is lowering them a nice to have? Personally, I would notch the double beams and drop them, then make iron brackets to support their notches on to the steels.
Frank

 

[^woody^]

You seem to need some long legged speedy hangers

http://www.toolstation.com/m/part.html?p=97632

 

[FRAN1870]

Sorry meant ceiling joists not rafters :/
The joist will sit under the new purlin stud wall ... Is there any regs guidance regarding reinforcing notched ends with brackets ?

I understand I can only notch them 1 inch ? Don't really want to fork out for more SE work tbh.

Which hangers should I get ?

 

[FRAN1870]

You seem to need some long legged speedy hangers

http://www.toolstation.com/m/part.html?p=97632

Thanks Woody ....

 

[FRAN1870]

Just another quick note .... This pojnt about available nail holes ? If there's a hole but nothing behind it because it falls below the joist, then how can I nail through all the hanger holes ?

 

[^woody^]

You don't. Just nail what you can

 

[FRAN1870]

So this is ok then ?

Just wondering what stops the decking swinging ?

Do I just fix it to the ceiling joists to stop it moving back n forth ? or do I need some other form of lateral restraint ?

 

[^woody^]

Just wondering what stops the decking swinging ?

Nails and floorboards

 

[FRAN1870]

Yeah I just mean that it will want to pivot from the yellow line ( see sketch )

Even with the boards on top ?

 

[^woody^]

What has your designer specified?

The new floor should be independant of the existing ceiling joists to avoid cracking the ceilings.

The floor deck, tight between the beams might be enough to stop movement, otherwise some joists might need to pass under the beams and be fixed to them or on the back edge of the beam to provide bracing.

 

[FRAN1870]

I'll just add some steel restraints at a few places .. Should be fine