Joists pulling away from binder - ceiling sag

[golfdelta]

I noticed a crack developing in the ceiling around a year ago but it wasn't too bad so I didn't think much about it until repainting recently after the lockdown started.

When up the stepladder to do the cutting in I noticed that there was a reasonably significant looking sag and decided I'd better investigate.

I've removed the stored crap, previous half arsed decking and insulation and it looks like the nails holding three of the joists to the binder have started to pull away, presumably from a mixture of age and poorly distributed load from the half arsed boarding. The middle joist is about 2.5cm separated and either side about 1cm.

The binder isn't supported at the wall and isn't attached to the purlin so is just preventing deflection of the joists.

The joist span is the width of the living room, about 3.5m. The sag is in the spot where the loft ladder retracts to so is unfortunately exactly where you'd naturally stand to put stuff up in the loft.

Looking for advice on the simplest and cheapest way to pull the joists back up to the binder and remove the sag.

Also, feel free to chip in on how best to redistribute load when the boarding is relaid. I was thinking of putting in another timber parallel to the binder and supporting the boarding between the two so the load is spread across the joists more evenly.

 

[bobasd]

Are you saying that the Binder is simply free floating over the joists, & that neither of its ends are resting on supportting walls for instance - further that there are no hangers tieing the Binder to the purlin?

The Binder must be supported - long Binders are hung from the Purlins and supported at either end.
You've got to stop using the loft for storage or traffic, and do some Remedial supporting work on the Binder or Binders.

Below you will have to prop the ceiling more or less level.
And then tie the joists into the Binder with say Simpson Angle Plates.

Hangers are often removed when the loft is used for storage.
Older loft joists were undersized in section for the spans they crossed.

 

[golfdelta]

The building is from about 1900. Doesn't look to me like the binder was ever attached with hangers and definitely not supported.

It's kind of half way between the two pictures below: purlin (supported on brickwork), purlin struts and binder present but no hangers and looks like three ties were added later.

Screenshot_20200415-191033_Firefox_Beta

• golfdelta
• 15 Apr 2020

https://fet.uwe.ac.uk/conweb/house_ages/elements/section5.htm

 

[catlad]

Probably best to lose the old binder and buy some 3x2" instead. Once supported under neath screw some 4" screws into your ceiling ties ( 2 each) pilot hole if necessary, and then some hangars to the purlins.