Balcony leading to flat roof....does it need fall protection?

[Thorfun]

2 hours ago, George said:

The Building Regulations can't cover every eventuality but it'd be Part K. I would say that because there is no fall risk along that edge then you do not need the full edge protection. It would essentially be a 'demarcation' barrier.

 

However, I would make the demarcation barrier suitable for p3.3 in Part K - that is, it can't be climbed over/defeated by children. So it'd basically have to be full edge protection except for the full restraint forces... so in reality, probably just the same as along the other two edges.

 

Note that the flat roof area does need to comply with p3.4 as green roofs do need occasional maintenance, so be prepared to justify the lack of guarding on that section of roof.  

 

thanks @George. As an SE can you answer my question i posed above to Gus as to whether it's possible to design a balustrade to withstand the forces for fall protection where the posts do not fix to the parapet? happy to fix to the house where the parapet meets the house though as we won't have to penetrate the waterproofing there.

 

if that's not even possible we can move on to find another solution and i won't spend any more time on it!

[PNAmble]

5 hours ago, George said:

Note that the flat roof area does need to comply with p3.4 as green roofs do need occasional maintenance, so be prepared to justify the lack of guarding on that section of roof

print a sign and stick it somewhere which says warning risk of fall:   Green roofs need maintaining twice a year.  Assuming it rains.   

Edited May 31 by PNAmble

[saveasteading]

A thought.

vertical post bolted to the outside end walls. Stainless tension cables linking the two.

The posts can readily be made to suit, and colour coated, and not very costly.

The posts can be made with whatever offset is needed to get past coping stones, and may be quite long to withstand the tension, but will otherwise be neat yet do the job.

[scottishjohn]

13 minutes ago, saveasteading said:

may be quite long to withstand the tension, but will otherwise be neat yet do the job.

longer they  are the more load on the fixings and the thicker the tube section will need to beand big the mounting plate to spread the load 

 two fixing plates down the outside wall  with space between them  out will be best 

 remeber what euclid said 

"give me a lever long enough and i will move the world"

Edited May 31 by scottishjohn

[George]

On 31/05/2024 at 16:33, Thorfun said:

thanks @George. As an SE can you answer my question i posed above to Gus as to whether it's possible to design a balustrade to withstand the forces for fall protection where the posts do not fix to the parapet? happy to fix to the house where the parapet meets the house though as we won't have to penetrate the waterproofing there.

 

if that's not even possible we can move on to find another solution and i won't spend any more time on it!

I think if it was steel structure, say forming a u shape back to the sides then it's a straightforward design job. The devil will be in the details.

 

Usually edge protection is not designed to that detail by the SE - essentially the supplier would do it using whatever standard system they sell and the SE checks the forces on the main structure.

[Gus Potter]

On 30/05/2024 at 21:04, Thorfun said:

@Gus Potter quick question and out of interest.....is it possible for an SE to design a balcony that could resist the forces required to pass building regulations WITHOUT having fixings on the long side of the balcony? as said we can fix to the outside of short sides through the cladding and in to the timber of the balcony.

Hiya.

 

Been busy with the day job but saw this post. Here are my thoughts..

 

It's got to start with the Architectural appearance.. I think when you look out the doors you need to see something slender on elevation. In other words you don't want to be seeing a heavy top hand rail on elevation or heavy ballusters. I thought.. try horizontal tension wires for the ballusters.. but they are climbable for kids.. rule that for now.. but look on the internet how pubs etc do it where they have a heavy handrail and cantilever it in to make it difficult to climb.

 

Structurally I would look at taking some pretty slender corner posts up from the side walls (to the left and right of the doors at the green roof end) say 50 x 50 mm box section as it allows you more scope for fixing them through the cladding at the bottom. I would then form a standard welded guard rail / balusters with a bottom runner, maybe 20mm box section as ballusters and a top rail of your choice. This will be pretty stiff and will carry lots of load along it's plane. Normally we design these things to resist load perpendicular to the hand rail. We still do this but do some extra checks to get the hand rails to deliver more.

 

This is the key as now you have something cup the side to the left and right of the doors that will stop the section parallel to the green roof form moving towards or away from the doors.

 

To design the bit that separates the green roof from the balcony I would do the same as above but make the top rail out of.. (I'm guessing here as don't know the length) say 180 x10mm steel flat plate. This on elevation is a thin profile and would also give you a shelf you can sit you morning coffee and croissant on.. or whatever.

 

To design this structurally it's quite complicated as you need to know about fixings and stiffness of a typical hand rail / balluster assembly. One secret is to avoid bending forces in and around the fixing location and convert all the forces to shear forces that better suit fixings. Proving it takes a bit of effort.

 

Design cost say two and a half days to; draw it Architecturally and get the look right, do the calculations including fixing design, do a steel fab drawing and explain to others what they should be doing and answer any later questions that folk phone you up about and a bit of a hassle factor.

 

Call that £1200 ex vat.. seems a lot but you pay for the expertise and knowledge. You can save the vat if you find an SE / designer that sticks below the vat threshold. Mind you you could easily blow much more than my budget design fee if you get it wrong.. also you'll have to live with it if it looks rough.

 

Think of slender, breakfast or some G&T on a nice night sitting on that flat handrail  plate.. no worries about puncturing the roof and it leaking in the winter!

 

 

 

 

 

 

 

 

[Thorfun]

10 hours ago, Gus Potter said:

Hiya.

 

Been busy with the day job but saw this post. Here are my thoughts..

 

It's got to start with the Architectural appearance.. I think when you look out the doors you need to see something slender on elevation. In other words you don't want to be seeing a heavy top hand rail on elevation or heavy ballusters. I thought.. try horizontal tension wires for the ballusters.. but they are climbable for kids.. rule that for now.. but look on the internet how pubs etc do it where they have a heavy handrail and cantilever it in to make it difficult to climb.

 

Structurally I would look at taking some pretty slender corner posts up from the side walls (to the left and right of the doors at the green roof end) say 50 x 50 mm box section as it allows you more scope for fixing them through the cladding at the bottom. I would then form a standard welded guard rail / balusters with a bottom runner, maybe 20mm box section as ballusters and a top rail of your choice. This will be pretty stiff and will carry lots of load along it's plane. Normally we design these things to resist load perpendicular to the hand rail. We still do this but do some extra checks to get the hand rails to deliver more.

 

This is the key as now you have something cup the side to the left and right of the doors that will stop the section parallel to the green roof form moving towards or away from the doors.

 

To design the bit that separates the green roof from the balcony I would do the same as above but make the top rail out of.. (I'm guessing here as don't know the length) say 180 x10mm steel flat plate. This on elevation is a thin profile and would also give you a shelf you can sit you morning coffee and croissant on.. or whatever.

 

To design this structurally it's quite complicated as you need to know about fixings and stiffness of a typical hand rail / balluster assembly. One secret is to avoid bending forces in and around the fixing location and convert all the forces to shear forces that better suit fixings. Proving it takes a bit of effort.

 

Design cost say two and a half days to; draw it Architecturally and get the look right, do the calculations including fixing design, do a steel fab drawing and explain to others what they should be doing and answer any later questions that folk phone you up about and a bit of a hassle factor.

 

Call that £1200 ex vat.. seems a lot but you pay for the expertise and knowledge. You can save the vat if you find an SE / designer that sticks below the vat threshold. Mind you you could easily blow much more than my budget design fee if you get it wrong.. also you'll have to live with it if it looks rough.

 

Think of slender, breakfast or some G&T on a nice night sitting on that flat handrail  plate.. no worries about puncturing the roof and it leaking in the winter!

 

 

 

 

 

 

 

 

thanks Gus. all seems to make sense, kind of! and it's good to know that it is possible.

 

it is a balancing act of aesthetics, cost and risk and we need to decide which route we want to go. 

[Alan Ambrose]

>>> you can sit you morning coffee and croissant on

 

😀

[Gus Potter]

On 05/06/2024 at 10:32, Alan Ambrose said:

you can sit you morning coffee and croissant on

That is me appealing to the refined..hey you can just go out with a cup of tea and hopefully have some pants on so as not to offend.

 

On 05/06/2024 at 08:08, Thorfun said:

all seems to make sense, kind of! and it's good to know that it is possible.

Yes it is.

 

For all on BH you may wonder if I'm having a laugh saying I would estimate an SE design fee of £1200.00 maybe plus vat.

 

The actual SE work maybe only accounts for 50- 60% of the above fee. I know from experience that I could spend at least a day, maybe two  trying to elicit the information and drawings from a Client / Builder so I can design the fixings and get the appearance / buildability right.

 

If you want to get the best out of an SE give them the best info you have.. the more you make them guess the more expensive it becomes.

 

 

Edited June 7 by Gus Potter

[PNAmble]

Just to support @Gus Potter, ive kept my SE on throughout, every time we had a questions; be it foundation design, drainage, fire escape , guarding, flat roof support or anything else they have been brilliant developing solutions both off the shelf and bespoke from a fees cost perspective they have saved

me £££,  we’ve discussed every solution including final look. 

 

I’d say they’ve saved us about 7-10% of my build cost compared to the architect ‘solutions’.   But we’ve put in the effort with them. 
 

 

 

 

[Gus Potter]

Just now, PNAmble said:

Just to support @Gus Potter, ive kept my SE on throughout, every time we had a questions; be it foundation design, drainage, fire escape , guarding, flat roof support or anything else they have been brilliant developing solutions both off the shelf and bespoke from a fees cost perspective they have saved

Thank you for the kind words. I'm an SE and an Architectural deisgner as the day job.

 

@PNAmble that is the kind of SE you need on a self build. SE's know a lot of stuff about other stuff and some of us will chip in to make sure you get looked after.

 

Caution: Not all SE's are like this.. some.. I would never have anywhere near my projects.. I sometimes work as an SE on behalf of Contractors. I have a job on my books and the response from the main SE is bordering on me reporting him to the IStructE for negligance... but the Client will probably do this first. .. not all SE's are angels, some have an attitude problem.

 

 

 

 

[George]

1 hour ago, Gus Potter said:

Thank you for the kind words. I'm an SE and an Architectural deisgner as the day job.

 

@PNAmble that is the kind of SE you need on a self build. SE's know a lot of stuff about other stuff and some of us will chip in to make sure you get looked after.

 

Caution: Not all SE's are like this.. some.. I would never have anywhere near my projects.. I sometimes work as an SE on behalf of Contractors. I have a job on my books and the response from the main SE is bordering on me reporting him to the IStructE for negligance... but the Client will probably do this first. .. not all SE's are angels, some have an attitude problem.

 

 

 

 

Ooh tell us more.

 

There is CROSS for anonymous safety reporting as well.

[Gus Potter]

On 07/06/2024 at 23:24, George said:

Ooh tell us more.

 

There is CROSS for anonymous safety reporting as well.

 

@GeorgeI am signed up to CROSS and an SCROSS so get all the notifications.. surely you don't think I'm not keeping up?

 

No.. George..  I'm not going to tell you any more about your request to "ooh tell us more" but I can tell you this.. you are barking up the wrong tree.. I use my own name on BH.. would you care to expand on your statement and clarify?

 

Some of the software you use may.. I may have had a hand in the engineering development.. I used to spend loads of time writing pops up notes for general SE's (maybe like you) saying.. hey unless you really know your stuff then don't change the default values.

 

I have worked for well known SE Consultancies in the past and know how they can drop the ball. I can give you plenty examples of SE's who have failed and sometimes dangerously. I'm not going to do that in a Public forum.

 

Let's leave it George and stick to having fun sharing what we know on BH and ecouraging young folk.

 

 

 

 

 

 

 

 

 

Edited June 12 by Gus Potter

[George]

Quote

would you care to expand on your statement and clarify?

Oh it just sounded like there was more you could say but I wasn't expecting a name and shame exposé on BuildHub.