Steel Single Spine Staircase worries

[crispy_wafer]

I feel a bit daft asking, but I'm looking for advice as I may have jumped the gun a little. 

 

with my heart leading my head, I've had a Staircase fabricated at a local firm, and whilst I was getting carried away I didn't have any focus on what the staircase is sat on!  And now I'm trying to figure if, it'll be alright, or if I need to undertake additional work before attempting to install.  My ground floor is Block/beam, 150mm PIR, 70mm Cement based flow screed.  The closer I am getting to installing the more I suspect this isn't sufficient to bear the weight of this staircase, but I don't know for sure.  To complicate slightly I have 4 ufh pipes running under where the footplate of the staircase would sit - I did have the footplate made larger and bolt holes drilled away from where the ufh pipes are.

 

Are there any clever bods in buildhubland who can advise?

 

Thanks

Marek

[JohnMo]

12 minutes ago, crispy_wafer said:

Are there any clever bods in buildhubland who can advise

Build single storey - none of these headaches! 

[Mr Punter]

Get in touch with your floor beam supplier.  Tell them the weight of the staircase, the size of the footplate and the type of blocks you used.  If they can't give an answer your SE will.

[Nickfromwales]

1 hour ago, JohnMo said:

Build single storey - none of these headaches! 

That’s as helpful as………

 

Well, it’s just unhelpful.  

[Nickfromwales]

1 hour ago, crispy_wafer said:

I feel a bit daft asking, but I'm looking for advice as I may have jumped the gun a little. 

 

with my heart leading my head, I've had a Staircase fabricated at a local firm, and whilst I was getting carried away I didn't have any focus on what the staircase is sat on!  And now I'm trying to figure if, it'll be alright, or if I need to undertake additional work before attempting to install.  My ground floor is Block/beam, 150mm PIR, 70mm Cement based flow screed.  The closer I am getting to installing the more I suspect this isn't sufficient to bear the weight of this staircase, but I don't know for sure.  To complicate slightly I have 4 ufh pipes running under where the footplate of the staircase would sit - I did have the footplate made larger and bolt holes drilled away from where the ufh pipes are.

 

Are there any clever bods in buildhubland who can advise?

 

Thanks

Marek

You may be able to rebate a 20mm steel plate, and stand it on 9x 3” steel tubes, placed to avoid the pipes but to land on the substructure.
 

No matter how deep in the shit you are, there's always a Welshman with a way out lol. 

[saveasteading]

It will be fiddly.

I think you need to cut out a square of the screed, without touching the pipes.

Then cut down through the pir to expose the structure.

Then you will see whether you are on a block or beam.  

Fro there it is simple to form a concrete plinth up to floor level.

The size of the plinth will depend on the stair load and floor capacity,  which your SE must advise. 

OR a large plate that can bear directly on the screed. Again requiring a calculation. That may be ugly or "honest" depending on point of view.

[Nickfromwales]

@crispy_wafer ping me a PM if you want to speak about how to resolve, if you get stuck. 
 

SE is the next person, but you defo cannot sit it on the top layer as it’s a “dynamic” load. 

[Mr Punter]

This could be a good application for Compacfoam, so after you have cut out the screed and removed the insulation you can infill with Compacfoam and sit the staircase plate on that.

[JohnMo]

1 hour ago, Nickfromwales said:

That’s as helpful as………

 

Well, it’s just unhelpful.  

Take life less seriously - really wasn't meant to be helpful - just popped into my head reading the post 

[-rick-]

7 minutes ago, JohnMo said:

Take life less seriously - really wasn't meant to be helpful - just popped into my head reading the post 

 

Text based communication makes it harder to get intent across. In this case I'd say your post did not land well.

 

Having the first response to a 'help i may be in a sticky situation' post be 'well if you'd had made different decisions 2-3 years ago you wouldn't be in this sticky situaion' is particularly unhelpful.

[JohnMo]

9 minutes ago, -rick- said:

 

Text based communication makes it harder to get intent across. In this case I'd say your post did not land well.

 

Having the first response to a 'help i may be in a sticky situation' post be 'well if you'd had made different decisions 2-3 years ago you wouldn't be in this sticky situaion' is particularly unhelpful.

Only one useful post above, that's to get a structural engineer. Changes to original plans, adds complexity, things like this needs structural engineer input and design. Making it up with a bunch helpful strangers, isn't the correct way to do it in all seriousness.

 

1 hour ago, Nickfromwales said:

SE is the next person

 

[Beau]

I had to hack out around our UFH pipes after a change of stair plan. It was easy enough to chisel out the screed and I had a steel bracket fabricated that straddled the pipe and attached to the concrete below with injection resin studs.

Edited 4 hours ago by Beau

[saveasteading]

1 hour ago, saveasteading said:

  which your SE must advise. 

 

14 minutes ago, JohnMo said:

Only one useful post above, that's to get a structural engineer.

Me please, I said it too.

I'm afraid most of us write something casually sometimes: I know I have annoyed without any such intention.  Its the nature of the Hub.. we are not writing word perfect theses.

[saveasteading]

11 minutes ago, Beau said:

attached to the concrete below with injection resin

Along with a photo looking like my mouth these days..

 

@Beau I'm impressed how cleanly that came out. Was it slow and painstaking?

My concern would be that this is fine for a concrete slab. But in beam and block you could hit a block, which might fracture with a bolt into it, or hit a beam, which is very hard and has tendons in it, which on wouldn't want to cut.

 

But for a stair with only downward leading, you could simply rest on the base with no fixing.

[Beau]

17 minutes ago, saveasteading said:

 

 

@Beau I'm impressed how cleanly that came out. Was it slow and painstaking?

 

It was a long time ago but I have it my head that it was easier than I expected. The pipes are pretty robust and the screed had not bonded to it. Think I wetted the floor and turned up the heating to see where pipes might be and worked from there. A thermal camera would do the same 

[crispy_wafer]

Yeah I realise the only real answer is an SE, but sometimes it's good to talk and get stuff out there even if it means admitting to not thinking something through...  

 

Anyhoo where there is a problem, there is often a solution and maybe, just maybe somebody on t'internet may have just come across a problem similar to this in the past.  

 

Appreciate the comments nonetheless and I don't take anything to heart.  Am big enough and ugly enough to meet problems head on.  And yeah a bungalow would solve the problem 🤣. 

[crispy_wafer]

4 hours ago, saveasteading said:

OR a large plate that can bear directly on the screed. Again requiring a calculation. That may be ugly or "honest" depending on point of view.

Large plate as a load spreader to minimise point loads?  The bottom tread is going/was planned to be an large oak box type affair, so depending on if the plate is recommended by the SE then its likely to be covered...  We'll see

[crispy_wafer]

2 hours ago, Beau said:

I had to hack out around our UFH pipes after a change of stair plan. It was easy enough to chisel out the screed and I had a steel bracket fabricated that straddled the pipe and attached to the concrete below with injection resin studs.

crikey, good job, well done you!  I've got a very rough idea where my pipes are... and they are encased in conduit.  So if it comes to it I could cut and excavate, but only really as a last resort.

[crispy_wafer]

there's the 4 in question, you know they are there because the staircase is due to have a wind at the base, and I left a nice big gap for a standard timber staircase to bear down away from pipework....

[Gus Potter]

5 hours ago, Nickfromwales said:

SE is the next person, but you defo cannot sit it on the top layer as it’s a “dynamic” load. 

Maybe yes or maybe no. 

 

Ok things happen. The first thing to ask is how big is the stair and how big is the load bearing on the floor and to check the beams are ok.. this is important in terms of safety. 

 

Next is to recognise that with beam and block floors the bit under the stair may not be subject.. just can't be practically be often subject to the design load that the rest of the floor is designed for.. so you have potential spare capacity. 

 

Ok next we want to check the screed.. normally this is ok in direct compression. The screed depth sheds load..sideways so the bearing area of insulation is increased. Next we want to check the next layer down which is the insulation. This is likely the weak spot.

 

Post some details on what you have.. like good details so we can quantify the loads , base plate sizes, insulation type and so on. 

 

Don't dig out the screed at this stage until you have a handle on what might not be a problem. If you dig out the screed at this stage it could make things worse. 

 

Sometimes I design domestic stairs to deliberately be more vibrant, slender and thus more bouncy! So long as it safe then sometimes it's good for them to be a bit more "lively".

 

An example would be if leading up to a slender (but still safe) gallery, it a deliberate Architectural technique where the user feels they are going into a different type of space and you lead them on that journey.. up the lively stair! 

 

 

 

 

Edited 16 minutes ago by Gus Potter
To add a bit