Calculating load for Gallows Bracket (2009 thread)

[barkeep]

I have just converted a flat roof to a hip roof and now want to remove the steel support pole which currently supports the roof. I would like to use a gallows bracket as previously suggested by Noseall but dont know how to calculate the load in order to purchase the appropriately sized bracket.
Attached pics show how the roof is currently supported.

Untitled

• barkeep
• 5 Apr 2009
• 1

Untitled

• barkeep
• 5 Apr 2009
• 1

There are approx 300 tiles on the roof weighing approx 360kgs, plus woodwork.
Any help greatly appreciated.

Eric

 

[alittlerespect]

You would be better off closing off the canopy and creating an enclosed 'porch'. The recommendation is made as the gallows bracket may create as much of an obstruction as the existing stantion/support pole due to gallows bracket infringing upon the clear headroom.

If you want to go down the gallows bracket road you would need to have a structural engineer design one specifically for the task at hand as I doubt that you will get one of the shelf!

Regards

 

[noseall]

I disagree. At least by leaving it open there will still be a 'storm' porch, i.e. somewhere to dash into when raining and looking for keys.

A gallows bracket in the desired location will only be supporting a fraction of the total roof weight. I would have thought a bolted gallows would eat it.

 

[^woody^]

I would have cantilevered two timber beams in the roof void and done away with an ugly bracket

But in this case, 4x2 will do it, with the diagonal brace at about 2/3 the horizontal leg - which presumably must extend to at least where the post is to catch the hip

 

[barkeep]

thanks for your replies - grateful , as ever

Eric

 

[Davef1uk]

You won’t have 300kg of weight on that corner. Most the weight is taken on the brickwork.. a 800 x 900 gallow bracket bolted into brickwork would easily support that.

Construction is important. Dovetailed mortise tennon joints and made from nothing less than 100mm x 75mm or you can get a steel gallow made.