Nudura One series variation

[LadyBuilder]

Here is a question that has been bugging me...

 

We are looking to achieve 0.14-0.15 wall U-value, as air tight as possible

 

If we choose ICF for the house structure, the overall thickness of the wall ends up over 430mm thick including brick slips and plasterboard, because of the 100mm insert. What if we were to use the one series by Nudura and dot and dabbed K5 Kooltherm insulation (e.g 100mm) to the concrete side, similar to a EWI? That would reduce the overall thickness of the wall.

 

What am I missing? Do you think it is a clever (although more expensive) way around it or am I forgetting something crucial? Any other innovative ideas?

 

We need to clad the house in brick slips...

[jamiehamy]

I don't follow you. What is the 'insert' and what is the 'concrete side' of icf? Icf uses insulation to create a shutter - which remains in place? 

[ToughButterCup]

50 minutes ago, jamiehamy said:

I don't follow you. What is the 'insert' and what is the 'concrete side' of icf? Icf uses insulation to create a shutter - which remains in place? 

 

The ICF Durisol has the insulation in the outer half of the block and concrete on the inside of it. Both those materials are 'shuttered' within a  wooden form held together by cement.

[Ian]

@LadyBuilder

I googled “Nudura One” and I see that it’s an option within their system for ICF with the insulated former on only one side  which I can see could be useful for lift and stairwell walls. However, I’m not sure what you mean when you talk about omitting “100mm inserts”. What are the inserts and what are they made of?

Edited December 14, 2017 by Ian

[Stones]

Our house is built with Amvic ICF -  65mm polystyrene / 150 concrete core / 65mm polystyrene. Additional insulation fixed to the outer face of the ICF block, rendered / clad thereafter.

[LadyBuilder]

2 hours ago, Ian said:

@LadyBuilder

I googled “Nudura One” and I see that it’s an option within their system for ICF with the insulated former on only one side  which I can see could be useful for lift and stairwell walls. However, I’m not sure what you mean when you talk about omitting “100mm inserts”. What are the inserts and what are they made of?

Nudura explained that their standard blocks have a U-value of 0.24. To get down to 0.15, they have an 'insert' of another 100mm EPS, which somehow slots in the formwork (awaiting the actual details):

 

' The estimate for the 0.15 U Value uses 250mm core with 100mm inserts giving an overall unfinished wall width of 387mm. '

[A_L]

 

@Ian The inserts can been seen on page 24 here - http://www.nudura.com/docs/default-source/brochures/nudura-product-guide.pdf?sfvrsn=4

They seem to go inside the form and do not increase its width.

 

@LadyBuilder 55mm of K5 has the same insulating effect as 100mm of the polystyrene they use

 

 

 

[LadyBuilder]

6 minutes ago, A_L said:

@Ian The inserts can been seen on page 24 here - http://www.nudura.com/docs/default-source/brochures/nudura-product-guide.pdf?sfvrsn=4

They seem to go inside the form and do not increase its width.

 

Thanks for this! I see now how they fit in. Unfortunately I do not agree with you, they do increase the width. I believe you use a bigger block, because otherwise you end up with of 50mm concrete which will have no load bearing capabilty

Edited December 14, 2017 by LadyBuilder

[AliG]

You are right, the wall gets wider as they add the Inserts, they use longer ties between the two sides of the ICF.

 

You could add 62.5mm insulated plasterboard to standard ICF with no inserts. this would give around a 0.15 U-Value. I would not get too worried about 0.01 of U-Value here or there in the walls as you can regain it in the roof, windows or floor.

 

The interior plasterboard can be mechanically fixed to ICF and any cables in exterior walls channeled into the EPS. In our house we found that virtually all services went in interior walls anyway.

 

This would give around a 330mm thick wall, assuming a 100mm core.

 

You would get a similar thickness with 0.18 U-Value ICF with a 50mm insert. Depending on the cost the extra insulation may not pay for itself.

 

 

 

 

 

 

 

[Alexphd1]

I have used the nudara 150mm inserts. We started with 60mm (there or there abouts) insulation = 300mm cavity = 60mm insulation then ww added 150mm insert so we have 210mm insulation 150mm cavity (concrete) 60mm insulation. For using the 100mm insert you start with a narrower block with 250mm cavity (concrete). We are a planning to building a second house with this system but using a different nudara block.

[LadyBuilder]

Thanks everyone for this. Has anyone used the one-series or the spider tie formwork that was posted in the basement forum

[Alexphd1]

On 18/12/2017 at 10:20, LadyBuilder said:

Thanks everyone for this. Has anyone used the one-series or the spider tie formwork that was posted in the basement forum

 

Yes & yes. Any questions just ask.

[SNO man]

On 27/01/2018 at 22:25, Alexphd1 said:

 

Yes & yes. Any questions just ask.

Hi Alex,

 

How was your experience with OneSeries?  I'm really keen to get close to passive EPS thickness, but would prefer keeping the thermal mass all on the inside of the building (and quite like the idea of exposed concrete on some walls and keeping the OSB formwork on for others, to attack drywall).

 

I've only found one example online of a newbuild using one sided Nudura, and it seems their builder went massively overkill on extra bracing, to help ensure it stayed true (I think they worried EPS one side of the formwork and wood on the other might be likely to compress more on one side, or be harder to true-up with normal braces).

 

Do you have any pics and feedback?  I'm planning to build a 4 storey in London and basement under the lower ground will probably not be ICF as we are digging/building to edge of plot with no external access at the sides.

 

cheers

[Simplysimon]

welcome @SNO man, no experience with ICF, but you've mentioned a term which will have others flocking to reply!?

[SNO man]

On 18/01/2022 at 20:10, Simplysimon said:

welcome @SNO man, no experience with ICF, but you've mentioned a term which will have others flocking to reply!?

hope so !

[Russell griffiths]

What do you mean by passive eps thickness. 

Nudura new blocks have something like 100mm inside and outside, 

why do you want the ply to attach things to, the blocks have the plastic ribs every 8 inches plenty of attachment points, this week I fitted 18mm osb over my walls in the kitchen area, used imperial osb and it lines up perfectly with the blocks. 

If you want a bare concrete wall then you can do it there, but no need to do it anywhere else. 

Dont make it harder than it needs to be. 

[FM2015]

1 hour ago, Russell griffiths said:

What do you mean by passive eps thickness. 

Nudura new blocks have something like 100mm inside and outside, 

why do you want the ply to attach things to, the blocks have the plastic ribs every 8 inches plenty of attachment points, this week I fitted 18mm osb over my walls in the kitchen area, used imperial osb and it lines up perfectly with the blocks. 

If you want a bare concrete wall then you can do it there, but no need to do it anywhere else. 

Dont make it harder than it needs to be. 

The word is that the Nudura xr range is designed for a 70 Deg external temp swung between coldest and warmest!  Bit over specced for the UK's temperate climate.  More cost effective options are offered by Nudura.

[Russell griffiths]

I believe we have a big problem in our heads about u value. 

The standard Nudura blocks on paper look terrible, but combine that with good build quality and an airtight building and it’s all you need. 

In my humble opinion. 

[PaddyP]

I used the Amvic Passive 350mm block. This gives a u-value of 0.15. It is 100mm insulation 150mm concrete 100mm insulation. Would recommend the Amvic system but not haven't used any others to compare against.

[BotusBuild]

3 hours ago, Russell griffiths said:

combine that with good build quality and an airtight building and it’s all you need. 

Totally agree - exactly how I am proceeding

[SNO man]

Paddy

Yes, I looked at the new Amvic 350 Passive but think we can get good enough with the R30 they have, or Nudura equivalent.

I was looking at Amvic because it happens to be the favourite of a local ICF builder who is also a basement specialist, so hoping to do a deal with him for complete shell (hoping to keep in-budget with me labouring alone on some things, like ICF build between pours).

Where did you get your Amvic 350?  They seem not to have it at at the Ireland HQ yet.

 

Russell

Thanks Russell.  I should have provided more detail, so it was a bit of a lazy post/question.  Here's a bit more thinking behind the query:

Q: What do you mean by passive eps thickness.

A:  I mean "getting close to a thickness of EPS that's needed for Passive House levels of insulation" (don't need totally Passive level, as we're in London and can't afford the wasted square-footage of crazy-thick walls)

Q: Why do you want the ply to attach things to, the blocks have the plastic ribs every 8 inches plenty of attachment points, this week I fitted 18mm osb over my walls in the kitchen area, used imperial osb and it lines up perfectly with the blocks

A:  No they don't for the OneSeries, which is a "one-sided" ICF >> EPS with ribs outside house as normal, and wooden formwork on inside, which you can either remove for a clean concrete face (I really like that cool industrial look for our main living area) or leave it on if you want to attach conventional drywall.  nudura.com/products/nudura-one-series/

Q:  If you want a bare concrete wall then you can do it there, but no need to do it anywhere else. 

A:  The only reason I'm interested in doing it everywhere, is to keep all the insulation on the outside of the thermal mass.  This keeps the thermal mass of the structure structure at the temperature of your living area, rather than half way between inside and outside... and in theory keeps internal temp more "even" (because your living area is not insulated from your thermal mass by an internal layer of EPS).

Q: Dont make it harder than it needs to be. 

A: Wise words.  So I'll probably drop the 1Series idea and just using something with similar values to the Amvic R30, but worth asking around first I thought.

 

[PaddyP]

I got the Amvic 350 block directly from Amvic. I am in Ireland myself and got it directly from their factory to my site. This was last summer so not sure what their current situation is like. I dealt with Alan and Cillian in Amvic, both were very helpful.

[SNO man]

Any chance you still have an email address for those two lads Paddy?

Edited January 21, 2022 by SNO man
clearer language

[SNO man]

Thanks Paddy - just emailed them now.

[FM2015]

I would also look at the actual real world cost of the OneSeries versus a more traditional shuttered system.  Ultimately if you throw enough concrete at it, the EPS/insulation becomes less relevant to the overall performance.  The OneSeries is not a particularly first time user friendly product and complicated designs make it even less worthwhile in your scenario.