Internal Steps - How to build...

[Mulberry View]

I have 2 ground floor level changes. 600mm from Entrance Hall to Kitchen/Dining and 400mm from Dining Room to Living Room. Here is the Kitchen one...

 

 

We anticipate Microcement to the whole Ground Floor with UFH under. Here is the Architects general arrangement drawing for a level change, which showed the steps built (presumably from Timber) on top of the screed. *Note - The Architect is (thankfully) not on the project any more*

 

However, I want them to be monolithic with the main floor to give the Microcement the best chance and so want to build them from concrete blockwork, which I would decouple from the floor on Marmox blocks, just as I did with the internal walls, then oversail the PIR and Screed, incorporating the top step into the main floor without a joint, hence I terminated the ICF level with the Beam & Block. Here's what I have so far...

 

 

Any suggestions about how to build these steps? And how to run the UFH through them...

Edited February 5 by Mulberry View

[Nickfromwales]

Run the UFH through them? Maybe not squire!

 

I’d decide where movement is going to occur, and mitigate that in the design for these steps. 
 

Microcement has some tolerance, but you’ll need the top tread bound to the upper floor section to avoid a hairline crack happening where the step ends and flooring begins.

 

Timber would have been a disaster! Good call 🥾 👉 🚪 

[Mulberry View]

19 minutes ago, Nickfromwales said:

Run the UFH through them? Maybe not squire!

 

I’d decide where movement is going to occur, and mitigate that in the design for these steps. 
 

Microcement has some tolerance, but you’ll need the top tread bound to the upper floor section to avoid a hairline crack happening where the step ends and flooring begins.

 

Timber would have been a disaster! Good call 🥾 👉 🚪 

 

Whether or not the steps themselves will be heated, the pipes will need to travel between the 2 areas I imagine.

 

Do I need an Architect to design this?!

 

I'm glad to have done something right in thinking of this now before putting the screed down to the Architects plan.

[Nickfromwales]

4 hours ago, Mulberry View said:

I'm glad to have done something right in thinking of this now before putting the screed down to the Architects plan.

1000%.

Most architects suck at these things tbf, it’s not exclusive to yours 😉

 

If you have the manifold on the upper floor it’ll happily travel down to the lower and back up again. Having the manifold below the upper floor will just constantly trap air (gasses) and airlock and cause you ongoing grief a-plenty. How big an area, and have you got an UFH design done yet we can tear into shreds for fun? 😀

 

[Nickfromwales]

1 hour ago, Mulberry View said:

Do I need an Architect to design this?!

If you can use a pencil and a ruler you can have folk here help, by scrutinising options / designs, and get it over the line that way. The caveat is you roll the dice that were all not locked in padded cells   

[ETC]

Don’t forget to make sure the DPM is continuous between the two floor levels.

[Mulberry View]

14 minutes ago, ETC said:

Don’t forget to make sure the DPM is continuous between the two floor levels.

 

Do you mean the DPM that'll be over the top of the Insulation? As long as it's achievable, I'll do everything I can. I really appreciate all help, I'm fighting for my life on this build. 😆

[Mulberry View]

1 hour ago, Nickfromwales said:

1000%.

Most architects suck at these things tbf, it’s not exclusive to yours 😉

 

If you have the manifold on the upper floor it’ll happily travel down to the lower and back up again. Having the manifold below the upper floor will just constantly trap air (gasses) and airlock and cause you o going grief a-plenty. How big an area, and have you got an UFH design done yet we can tear into shreds for fun? 😀

 

 

Not got a design yet, but that's already some good info to start with. So, with the Living Room being the highest, are you saying I should have a manifold there? 🙈

 

Any tips on where I should go to get a UFH design done? Does it need to come after some sort of heat calculations as there is a whole other can of worms.

[Nickfromwales]

1 hour ago, Mulberry View said:

as there is a whole other can of worms.

Explain please, so we can advise best without kicking the can too much.

 

1 hour ago, Mulberry View said:

are you saying I should have a manifold there? 🙈

Yup, defo, or one manifold per floor if the space is there (that's what I did on a previous job almost identical to yours, with two sets of 3 steps up/down to the split levels of the ground floor. Depends on space obvs, so a better floor plan may also help please. Be sure to anonymise before posting  

[Nickfromwales]

1 hour ago, Mulberry View said:

Any tips on where I should go to get a UFH design done?

We can help here tbh, what's the heat source? ASHP I assume? Any quotes or spec in for that yet?

[Mulberry View]

3 minutes ago, Nickfromwales said:

Explain please, so we can advise best without kicking the can too much.

 

Yup, defo, or one manifold per floor if the space is there (that's what I did on a previous job almost identical to yours, with two sets of 3 steps up/down to the split levels of the ground floor. Depends on space obvs, so a better floor plan may also help please. Be sure to anonymise before posting  

 

I've made some reasonably substantial improves in build to those stated in the as-designed SAP. So, coming up soon on my agenda of things to do is how to convey these improvements to whoever I'll need to calculate heating needs.

 

Roof insulation improved from 120mm to 200mm (Warm roof)

Floor insulation improvement likely. 150mm in design, but I now have 275mm to play with on top of the B&B

Air Tightness was suggested as 3.0, but I'll be disappointed if I don't get under 1.0

Glazing improved from 1.1u in design to 0.8u in build

Glazing detailed for high-performance

 

etc. etc.

[Nickfromwales]

4 minutes ago, Mulberry View said:

 

I've made some reasonably substantial improves in build to those stated in the as-designed SAP. So, coming up soon on my agenda of things to do is how to convey these improvements to whoever I'll need to calculate heating needs.

 

Roof insulation improved from 120mm to 200mm (Warm roof)

Floor insulation improvement likely. 150mm in design, but I now have 275mm to play with on top of the B&B

Air Tightness was suggested as 3.0, but I'll be disappointed if I don't get under 1.0

Glazing improved from 1.1u in design to 0.8u in build

Glazing detailed for high-performance

 

etc. etc.

So you'll be having MVHR also?

[Mulberry View]

5 minutes ago, Nickfromwales said:

So you'll be having MVHR also?

 

Absolutely. It's a part of the build I'm greatly looking forward to.

[Nickfromwales]

4 hours ago, Mulberry View said:

 

Absolutely. It's a part of the build I'm greatly looking forward to.

DIY’ing then? Probably better to discuss that on a new thread lol. Just trying to get an overview so heat loss and UFH picture is clearer.

 

On that note, a full floor plan would help   

[Mulberry View]

12 hours ago, Nickfromwales said:

DIY’ing then? Probably better to discuss that on a new thread lol. Just trying to get an overview so heat loss and UFH picture is clearer.

 

On that note, a full floor plan would help   

 

As I said, I'm super grateful for all help. I'll start a thread to discuss MVHR and UFH with floor plans as I do need some help there.

 

I'm really trying to tick some of the boxes off that are haunting me on a daily basis, these steps are one of them. I'm determined not to build something that later has to be torn down. I do have an Architect doing some detail work for me, but it's very expensive and when you've already had to virtually sell a kidney to pay for the previous Architect, this is all very hard.

 

Oh and that's on top of having to go to court to sort out a Zinc Roof installation calamity. Honestly, it's no myth that self-building is hard.

[Nickfromwales]

22 hours ago, Mulberry View said:

Any suggestions about how to build these steps? And how to run the UFH through them...

Apologies for the digression. 
 

So, I see the b&b flush to the top of ICF, and then in the background I see the opening for the doors / sliders(?), so what is the allowance for PIR over the b&b with an 75/80mm screed?

[Mulberry View]

1 hour ago, Nickfromwales said:

Apologies for the digression. 
 

So, I see the b&b flush to the top of ICF, and then in the background I see the opening for the doors / sliders(?), so what is the allowance for PIR over the b&b with an 75/80mm screed?

 

As I mentioned above, the total from top of B&B to planned FFL is 275mm, with the usual allowance for floor coverings (25mm?). So, I guess that gives me 300mm including the Microcement build-up, which I think is next-to-nothing (5mm or so).

 

You think I should be using traditional screed or flow-screed?

[Nickfromwales]

2 minutes ago, Mulberry View said:

 

As I mentioned above, the total from top of B&B to planned FFL is 275mm, with the usual allowance for floor coverings (25mm?). So, I guess that gives me 300mm including the Microcement build-up, which I think is next-to-nothing (5mm or so).

 

You think I should be using traditional screed or flow-screed?

Ok, thanks. I missed that. 
 

For accuracy, top of concrete is top of screed, and FFL is that inclusive of the floor covering, just to avoid confusion.

 

So your FFL (the top side of the MC (microcement)) will be 305mm above b&b.   

 

If this was my build, just because how particular you’ll need to be with MC, I’d used cemflow (liquid cementitious screed) at 80mm and possibly consider some stainless anti crack mesh at the area of the top step for belt & braces.

 

Ill try and draw a cross section of how I’d make the steps up a little later today. 

[Mulberry View]

1 hour ago, Nickfromwales said:

Ok, thanks. I missed that. 
 

For accuracy, top of concrete is top of screed, and FFL is that inclusive of the floor covering, just to avoid confusion.

 

So your FFL (the top side of the MC (microcement)) will be 305mm above b&b.   

 

If this was my build, just because how particular you’ll need to be with MC, I’d used cemflow (liquid cementitious screed) at 80mm and possibly consider some stainless anti crack mesh at the area of the top step for belt & braces.

 

Ill try and draw a cross section of how I’d make the steps up a little later today. 

 

My Architect definitely didn't draw it like that. She refers to FFL as being 'to screed' and then shows 'Final Finishes' on top of that. Is this abnormal?

 

I built my structure so that the door openings terminate at what she has referred to as FFL, but all my floor level openings have been re-detailed so I can adjust them now if needed. I'll be removing the Nudura top closer and replacing it with Compacfoam to bear the weight of the heavy Triple-Glazed doors.

 

[Nickfromwales]

TOC (top of concrete) is what I’ve always seen as the top of raft / screed, and FFL is exactly that, your finished floor level (so not your unfinished floor level  ) unless I’m going mad, which is possible.

[Mulberry View]

27 minutes ago, Nickfromwales said:

TOC (top of concrete) is what I’ve always seen as the top of raft / screed, and FFL is exactly that, your finished floor level (so not your unfinished floor level  ) unless I’m going mad, which is possible.

 

I'm totally with you by the way. FFL is 'Finished' floor level.

[Nickfromwales]

27 minutes ago, Mulberry View said:

 

I'm totally with you by the way. FFL is 'Finished' floor level.

 

Given how much they get paid....why are a lot of architects quite so shit at their jobs? 🤷‍♂️

[ETC]

36 minutes ago, Nickfromwales said:

 

Given how much they get paid....why are a lot of architects quite so shit at their jobs? 🤷‍♂️

How many posters knew EXACTLY what their floor finish was going to be at BC submission stage? Architects can only determine FFL to screed if finishes aren’t determined.

[ETC]

4 hours ago, Mulberry View said:

 

My Architect definitely didn't draw it like that. She refers to FFL as being 'to screed' and then shows 'Final Finishes' on top of that. Is this abnormal?

 

I built my structure so that the door openings terminate at what she has referred to as FFL, but all my floor level openings have been re-detailed so I can adjust them now if needed. I'll be removing the Nudura top closer and replacing it with Compacfoam to bear the weight of the heavy Triple-Glazed doors.

 

No DPC?

[Nickfromwales]

14 minutes ago, ETC said:

How many posters knew EXACTLY what their floor finish was going to be at BC submission stage? Architects can only determine FFL to screed if finishes aren’t determined.

More my point of their mixed up and confusing statements of what is and isn't industry standard and recognised terminology....

 

But I do like the way you came running into the room ready to defend lol. Easy tiger, there's a good few ones out there too .

 

We always give indicative FFL and state how that was decided, and the client can then chop & change with a much greater understanding of the impact when they DO then go on to change their mind; as you rightly say, a LOT changes along the way in a self-build, as most are of course reasonably clueless at the outset, but they become pretty clued up towards the end and then the fun starts  A good architect will be the one who prepares the client vs catches them when they fall. I've seen waaaaaaaaaaaaaaaaaaaaaaay too many of the latter, and the fees they charge to 'put it right' at the 11th hour.