Garage with roof spread and rafter tie solutions

[mickf9]

I have a detached garage with roof spread, no rafter ties but collar ties present up in the top third. The walls are hollow 9 inch block and the roof spread has caused vertical cracking on each of corner, side edge. The cracks are right through the blocks, maximum is 5mm, so ill need to put helical bars in once i sort the roof spread.

Problem is, the span is 22 ft across and i can get rafters this length for rafter ties but there will be alot of sag in the middle. I found some advice online saying that i can hang 2 by 4s down from the rafter tops and attach them to a horizontal timber attached on top of the ties, to stop the sag. I eventually plan to plasterboard the rafter ties. Other advice is saying this would be too heavy a load for the hangers. And would cause the ridge to sag.

As this is a garage, i would prefer to leave the open space. I could put a I beam up the centre of the garage but would need a heap of construction work to strengthen the garage door lintel and walls, deepen concrete to take the load of the beams etc.

Any ideas to deal with the issues or am i gonna have to spend a fortune to sort this out?

 

[stevie888]

The key word is tie.

A bit of steel cable or a steel rod would stop the spread. Judicious detailing with some threaded connectors would allow you to pull the walls back even

 

[mickf9]

The key word is tie.

A bit of steel cable or a steel rod would stop the spread. Judicious detailing with some threaded connectors would allow you to pull the walls back even

Thanks would steel rod / cable be used wall to wall, not to tie the rafters though in place of rafter ties? I wouldnt have space to leave cables wall to wall in place.

 

[stevie888]

You'd tie the wall plares together. doing what ceiling joists usually do.

Why on earth would you not have room for a bit of wire when you're talking about using timber??

 

[mickf9]

You'd tie the wall plares together. doing what ceiling joists usually do.

Why on earth would you not have room for a bit of wire when you're talking about using timber??

Ok tie wallplates together, wasnt sure if you were suggesting going through walls themselves to pull them back plumb.

How would you attach to the wall plates though? if i put eyebolts straight through the sides of the wall plates (looks like 2 × 4) and would i be safer taking the weight off the plates by pushing rafters up slightly using a few acrows on a temporary attached timber across the rafters to distribute the lift?