Cantilever stairs

[Evs]

Has anyone designed or made their own cantilever stairs? I’ve been looking at how they’re made and it doesn’t seem too difficult. I’m sure if I get the dimensions of everything I could take it to a good fabricating shop and they could cut and weld all the steel for me. Then its just getting the treads made to slide over the top of the steel. I was thinking of getting something like this made up instead of having a 10mm thick plate anchored to the full the full length of the stairs from top to bottom. 

The wall is made of standard concrete block and is load bearing so will be fine to anchor to. 

 

Other than getting my own made I’ve looked online on Fontanot but they don’t seem to be able to do the colour I’m after. Has anyone got any experience with any other websites that you can buy them from that are not stupidly expensive? I’ve looked on a couple of sites and prices were starting from £10,000-£12,000 which I don’t intend paying that much. I also need 2 of these stair cases. 

 

Found this website which is very informative. 

https://homedesigntutorials.com/2017/08/12/how-to-design-a-cantilevered-staircase/

 

Edited February 20, 2021 by Evs

[Oz07]

someone here has done it im sure..search perhaps but might be hard

[Mr Punter]

Now there is a task I would not fancy taking on!  Can you keep us updated with progress?

[Thorfun]

9 minutes ago, Mr Punter said:

Now there is a task I would not fancy taking on!  Can you keep us updated with progress?

agreed! this is one outcome I'd really like to know as we're thinking of cantilevered stairs but are worried about the expense.

[Evs]

Yeah I’ll keep the thread updated with how I get on. 

The calculations look daunting at first but after studying them for a bit it doesn’t seem as bad as I first thought. The bit that may be tricky is adding glass balustrade to the stair case that is also supported by the wall fixture, but the weight of the glass is shared between however many treads each piece of glass spans.

I can imagine loads of people have had them made without doing any structual analysis. Its if BC ask for it and you haven’t got it there’ll be a bit of trouble. 

[Trw144]

We have installed cantilever stairs. In our case we had a steel frame and steps made by the timber frame company (as we needed some supporting steel work anyway), so I can't help with that bit. The treads were made as a wooden sleeve slid over the steels and glued in place. Glass then screwed into the end of the steel box section, followed by an end piece of wood to hide the fixings. I believe I posted pics on here at the time (4 years ago ish) but can probably find them again if there is anything you wanted to see

[Onoff]

14 minutes ago, Trw144 said:

We have installed cantilever stairs. In our case we had a steel frame and steps made by the timber frame company (as we needed some supporting steel work anyway), so I can't help with that bit. The treads were made as a wooden sleeve slid over the steels and glued in place. Glass then screwed into the end of the steel box section, followed by an end piece of wood to hide the fixings. I believe I posted pics on here at the time (4 years ago ish) but can probably find them again if there is anything you wanted to see

 

Here you go, the thread with pics of your stairs:

 

 

[Evs]

13 minutes ago, Trw144 said:

We have installed cantilever stairs. In our case we had a steel frame and steps made by the timber frame company (as we needed some supporting steel work anyway), so I can't help with that bit. The treads were made as a wooden sleeve slid over the steels and glued in place. Glass then screwed into the end of the steel box section, followed by an end piece of wood to hide the fixings. I believe I posted pics on here at the time (4 years ago ish) but can probably find them again if there is anything you wanted to see

Did building control require any structual analysis from you to ensure the fixings could withstand the load? 
From what you’ve said there it sounds exactly like what I want and how I was invisioning constructing it. 

[Evs]

1 minute ago, Onoff said:

 

Here you go, the thread with pics of your stairs:

 

 

Brilliant! Thank you for that??. 

[Trw144]

10 minutes ago, Evs said:

Did building control require any structual analysis from you to ensure the fixings could withstand the load? 
From what you’ve said there it sounds exactly like what I want and how I was invisioning constructing it. 

No, I'm pretty certain they didn't request a copy (although the loads were calculated by the SE when doing the timber frame). Seems strange looking back at my thread 4 years ago, I have some extra pics which may help here...

Edited February 20, 2021 by Trw144

[Trw144]

 

 

Edited February 20, 2021 by Trw144

[Thorfun]

@Trw144 they look amazing! it still amazes me that they can take a weight as they just seem to float. is there any bounce at all? even if you jump from stair to stair?

 

(off to read your 4 year old thread on them now)

[Trw144]

Finished view with the tread ends. Originally they were glued to the glass fixings, but I found they would rotate with the vibrations as you couldn't necessarily fix them tight enough. Instead I ended up pulling them off the fixing nuts and simply siliconing onto the glass separately.

[Evs]

14 minutes ago, Trw144 said:

No, I'm pretty certain they didn't request a copy (although the loads were calculated by the SE when doing the timber frame). Seems strange looking back at my thread 4 years ago, I have some extra pics which may help here...

Ok thats good but alteast you had them incase they wanted them.

 

Thank you for the extra pictures too, it all helps.

I think its slightly harder to add it to a traditional concrete block wall as the blocks are only 100mm thick and most anchor bolts that I have seen used are longer than 100mm. 

[Evs]

1 minute ago, Trw144 said:

Finished view with the tread ends. Originally they were glued to the glass fixings, but I found they would rotate with the vibrations as you couldn't necessarily fix them tight enough. Instead I ended up pulling them off the fixing nuts and simply siliconing onto the glass separately.

That looks beautiful and you’ve also got near enough the identical tiles we’ve been looking at too! 

[Trw144]

2 minutes ago, Thorfun said:

@Trw144 they look amazing! it still amazes me that they can take a weight as they just seem to float. is there any bounce at all? even if you jump from stair to stair?

 

(off to read your 4 year old thread on them now)

Once they are fixed to the glass, it braces up the entire structure so it feels really firm. Without the glass they would definitely feel a bit bouncy (using a wire system etc for the balustrade).

[Trw144]

1 minute ago, Evs said:

That looks beautiful and you’ve also got near enough the identical tiles we’ve been looking at too! 

Yes the tiling was probably the hardest job (not that I did it) as the tiles are so large they had to cut and align several holes for the treads in the same tile.

[Thorfun]

1 minute ago, Trw144 said:

Once they are fixed to the glass, it braces up the entire structure so it feels really firm. Without the glass they would definitely feel a bit bouncy (using a wire system etc for the balustrade).

We're planning to have vertical timbers for our balustrade. something like this.....

 

 

so would presume that the vertical timbers would help firm it all up. 

[Onoff]

5 minutes ago, Evs said:

most anchor bolts that I have seen used are longer than 100mm. 

 

What size bolts? What you're talking about is a bit different to how @Trw144 has done it! If going into blockwork I'd be looking at resin anchors.

[Trw144]

1 minute ago, Thorfun said:

We're planning to have vertical timbers for our balustrade. something like this.....

 

 

so would presume that the vertical timbers would help firm it all up. 

Yes in my experience you would definitely want those timbers to brace it together rather than just be aesthetic/balustrading 

[Thorfun]

thanks all. really given us something to think about.

[Evs]

3 minutes ago, Onoff said:

 

What size bolts? What you're talking about is a bit different to how @Trw144 has done it! If going into blockwork I'd be looking at resin anchors.

Sorry I didn’t explain that very well. Two websites I’ve come across that will build and ship them out to you to install yourself supply them with M12 x 180mm anchor bolts. 
 

I’ll definitely be using resin anchors for mine. 
 

 

[Mr Punter]

I think having the string fabricated with the stairs is probably easier to get right.  Mounting the treads individually would be more likely to fail structurally and be slightly misaligned.  The tiles provide an excellent finish.

 

A small slip when over-refreshed looks like it could be painful.

[Oz07]

Surely the fixing at top and bottom of these concealed metal strings is more important than any fixings inbetween?! If those two points are rock solid and it can't twist over then where's it going? Obvs would need someone qualified to give you fixing spec. 

[Evs]

12 hours ago, Mr Punter said:

I think having the string fabricated with the stairs is probably easier to get right.  Mounting the treads individually would be more likely to fail structurally and be slightly misaligned.  The tiles provide an excellent finish.

 

A small slip when over-refreshed looks like it could be painful.

 

Yes that is a good point if I was to get one made myself. 

One company supply a cnc machined template with the purchase that you mount to the wall so that when you install it, you drill every hole perfectly and every tread goes in the exact position its supposed to. 

Edited February 21, 2021 by Evs