Timber Juliet Balcony - Point Loads

[Barney12]

Warning: Long post. Questions at the end

 

OK, so I know we've got some really clever technical people in this parish so I've got a nice little technical question for you.

I have a feeling that allot of people are just going to say "use a structural engineer" but I like to understand things first as my experience is their insurance policies LOVE them to massively over-engineer. Here goes:

 

Our front dormer has a Juliet balcony. My planning conditions state it must be timber and the idea is it will match the brise soleil slats.

So I've been thinking that what I would really like to do is integrate the Juliet balcony into the cladding. Its taking from this sort of idea:

 

 

However, for reasons I'm not going to bore you with I've only got aprox 40mm of depth from the face of the window and the face of the cladding. Here's the actual dims of my dormer:

 

 

Now I've been doing some research and balconies need to meet a couple of point load requirements (as well as the height and gap elements of Part K of the building regs). As I understand it they are thus:

 

Rigid and strong, be able to resist and not bend, buckle or break under pressure. 

Durable and suitable to the area they are to be applied to.

 

Two British standards apply; BS6180:2011 "Barriers in and about buildings - Code of practice" which relates to the code of practice for balustrades in buildings and BS6399-1:1996 "Loadings for buildings - Part1: Code of practice for dead and imposed loads" which specifies the information on loadings.

 

For domestic dwellings this translates to:

 

Handrails: For external balconies 0.74 kN/m. This can be compared to having one averagely weighing person 75kg applying the full force of their body on every metre of the balcony.

Infill Panels/Rails: 0.5kN/m.

 

Now what I'd like to do is use the same cladding profile (20mm thick by 70mm) to create my infill panels. The handrail can be machined to sit on top using the same timber so that shouldn't be too much of an issue.

 

Because of the way the doors open I cant easily have a centre rail so the span is going to be 2.94m. I could though devise a way to attach a bar to the bottom of the dormer which would rise up the centre.

 

So, I was thinking that the solution would be to create a steel support behind the cladding. I can get the pieces of cladding that will make up the rails machined to accept this steel support. This is rough sketch of what I mean:

 

 

So now two my two questions:

 

1) Is this idea crazy?

 

2) Where/how can I calculate the point load strength of any bar design like the above?

 

Thanks for making it to the end!

 

 

[PeterW]

12 minutes ago, Barney12 said:

 

1) Is this idea crazy?

 

2) Where/how can I calculate the point load strength of any bar design like the above?

 

Thanks for making it to the end!

 

 

 

Its not a crazy idea and your "better" option is to create the strength in the steel. 

 

For example you are looking at a bending moment - steel works best in section so you could find that using a T shaped section that is clad above and below the flange is a better approach - 50x15 tee made of 5mm stainless would be pretty strong and is an off the shelf product. Yes, you would show a 5mm stainless edge but that could be a feature. 

 

 

[Barney12]

2 minutes ago, PeterW said:

 

Its not a crazy idea and your "better" option is to create the strength in the steel. 

 

 

Hurrah!

 

2 minutes ago, PeterW said:

For example you are looking at a bending moment - steel works best in section so you could find that using a T shaped section that is clad above and below the flange is a better approach - 50x15 tee made of 5mm stainless would be pretty strong and is an off the shelf product. Yes, you would show a 5mm stainless edge but that could be a feature. 

 

 

 

Yep, 5mm projecting could work.