Anybody using Velox ?

[Daniel Hornby]

Hi Guys and Gals

 

just a quick note here to say that I am builder and have been building with Velox now for nearly 6 Years. I have used it on many new build projects, any questions please don't hesitate to ask or email  me (email address removed).

[Grendel]

GBS used compacfoam 200 under the window and door thresholds on their Golcar passive house - fixed with threaded bar into the slab, to reduce thermal bridging. 

https://www.greenbuildingstore.co.uk/products/compacfoam-200/

I'm not linked to GBS in any way.

Has anyone considered the thermal bridging of Velox metal ties?? They did talk about a ??basalt?? tie 12 months ago, but they dont seem to have developed this.

Edited May 4, 2019 by Grendel
additional detail and clarification

[Tim Alsop]

On 04/05/2019 at 19:02, Grendel said:

Has anyone considered the thermal bridging of Velox metal ties?? They did talk about a ??basalt?? tie 12 months ago, but they dont seem to have developed this.

I have been told by many people that the metal ties have very minimal thermal loss. The alternative ties are not quite ready but I suspect in about 12 months they might be ready for use - they need to go through multiple approval steps.

[Daniel Hornby]

The thermal bridge of the metal ties is so small that it’s not really considered in calcs, there is a figure for for which I will dig out but don’t have to hand now. The easy solution if you were concerned by it would be to reduce the internal insulation by 50mm and add it back to the outside before rendering or whichever covering you have chosen. 

[Grendel]

On 07/05/2019 at 12:50, Tim Alsop said:

I have been told by many people that the metal ties have very minimal thermal loss. The alternative ties are not quite ready but I suspect in about 12 months they might be ready for use - they need to go through multiple approval steps.

 

That's reassuring about the ties, although 1000 ties with xsection of 1mm gives you a 10cm x 10cm bar of steel sticking through the structure

 

On 08/05/2019 at 13:48, Daniel Hornby said:

The thermal bridge of the metal ties is so small that it’s not really considered in calcs, there is a figure for for which I will dig out but don’t have to hand now. The easy solution if you were concerned by it would be to reduce the internal insulation by 50mm and add it back to the outside before rendering or whichever covering you have chosen. 

 

But would cost a lot in additional labour fixing the extra insulation on the outside! I guess I shouldn't be concerned

 

[Tim Alsop]

28 minutes ago, Grendel said:

But would cost a lot in additional labour fixing the extra insulation on the outside! I guess I shouldn't be concerned

Yes, exactly. I wouldn't be concerned if I was you. Velox is a good product even with these small bars.

[D Walter]

Hi, we cut off all the internal metal ties on our Velox build using an angle grinder.  We then used a face grinder to smooth the corner joints between Velox panels and glued and screwed plasterboard and skimmed.  The result is no void between the face of the Velox and the plasterboard and a beautifully smooth plaster surface.  Insofar as the metal ties act as a thermal bridge any impact of that has also been minimised.

[Tim Alsop]

10 minutes ago, D Walter said:

Hi, we cut off all the internal metal ties on our Velox build using an angle grinder.  

Did you cut off the external ties also before adding external cladding?

[D Walter]

Hi Tim,

We have clad about 1/2 of the external walls with vertical standing seem Tata Colorcoat Urban and did not cut off the external ties.  We are going to use Trespa Pura on the remaining 1/2 and don't think we will bother to cut off the ties.  We took the view that, particularly with the internal ties cut off, the external ties will make no appreciable impact on thermal bridging and will not interfere with our battens.

[Tim Alsop]

5 minutes ago, D Walter said:

Hi Tim,

We have clad about 1/2 of the external walls with vertical standing seem Tata Colorcoat Urban and did not cut off the external ties.  We are going to use Trespa Pura on the remaining 1/2 and don't think we will bother to cut off the ties.  We took the view that, particularly with the internal ties cut off, the external ties will make no appreciable impact on thermal bridging and will not interfere with our battens.

I'm interested in this type of cladding - do you have any photos to share ?

[scottishjohn]

just to play devils advocate 

you could argue that it is the outside ends of the wire bracing you should remove 

cos the internal ones will transfer heat to the concrete which is still inside the insulated outer layer and will act as a thermal store .

i doubt what ever you do the effect  will be measurable

[Alexphd1]

John, that was the main reason I stopped looking at steel tied ICF. 

[D Walter]

Hi Tim, do you mean Tata or Trespa Pura?  I can load pics of the Tat at this stage but will wait a bit till the scaffolding is down.  The Trespa will take a bit longer....

[Tim Alsop]

16 hours ago, D Walter said:

Hi Tim, do you mean Tata or Trespa Pura?  I can load pics of the Tat at this stage but will wait a bit till the scaffolding is down.  The Trespa will take a bit longer....

I am interested to see both. Thank you.

[Tim Alsop]

17 hours ago, D Walter said:

Hi Tim, do you mean Tata or Trespa Pura?  I can load pics of the Tat at this stage but will wait a bit till the scaffolding is down.  The Trespa will take a bit longer....

Regarding the Trespa. I have ordered some samples for my project. It looks like a nice product. Did you consider anything else similar ? Do you know the cost per square meter ?

[Russell griffiths]

7 hours ago, Tim Alsop said:

Regarding the Trespa. I have ordered some samples for my project. It looks like a nice product. Did you consider anything else similar ? Do you know the cost per square meter ?

Eye watering is what springs to mind

they quoted me about £70 

[Mr Punter]

I am always suspicious when is is near impossible to get a price on the internet for a product like this.

[Tim Alsop]

23 hours ago, Mr Punter said:

I am always suspicious when is is near impossible to get a price on the internet for a product like this.

This product is about half the cost - https://www.envirobuild.com/collections/composite-cladding-pioneer#collection and they have their price on website.

[D Walter]

The composite products like Hyperion do have their drawbacks.  They are most used in static caravan parcs. They are designed to have all the butt joins between boards in line with a vertical cover strip which is generally not what is looked for in a modern house.  I know people who have used staggered joints but it is tricky and the 10mm gaps between butt joints can be unattractive.  Additionally, the corner details for window reveals and corners of walls are wide mouldings.  Again, I know people who have cut the mouldings to a thinner profile but at some risk and a lot of work.

[D Walter]

On 13/05/2019 at 08:09, Tim Alsop said:

Regarding the Trespa. I have ordered some samples for my project. It looks like a nice product. Did you consider anything else similar ? Do you know the cost per square meter ?

The cheapest price I have had on Trespa is c. £85 per m2.  Some quotes were significantly higher (by about 25%).  There is also the cost of the corner profiles to consider.

[D Walter]

Sorry the picture is not great but this is the only bit of Tata without scaffolding at the moment.  When more of the scaffolding is down I will post some more pics including fascias and soffits and roof.

[Tim Alsop]

1 hour ago, D Walter said:

Sorry the picture is not great but this is the only bit of Tata without scaffolding at the moment.  When more of the scaffolding is down I will post some more pics including fascias and soffits and roof.

 

Thank you. Since this thread is about Velox and I am planning to build my house using Velox, can you share how you fixed this onto the Velox board ?

[Tim Alsop]

On 05/12/2018 at 20:35, D Walter said:

There are some swings and roundabouts, for example with 180mm of insulation outside the concrete thermal mass (great for utilising solar gain) we will need to bolt right angled steel plates to the outside end of the concrete first floor to support the massively heavy triple glazed lift and slide panes at first floor level, which effectively sit predominantly on unsupported EPS.  I don't have a good picture to illustrate this but if you look at the attached pic. you can see the horizontal cast beam which will be supporting the much smaller triangular windows under the first floor eaves.  Inside the external 35mm Velox cementboard face is 180mm of EPS, then 150mm of concrete then another 35mm inside face of Velox cementboard.   The triple glazed triangular windows will, again, largely be supported on the 180mm of EPS supported by shear strength and the 50mm Velox cementboard reveal strips below.  This is less of a concern here but the larger rectangular lift and slide panes below will require greater support. 

 

Hi

I had a meeting with Internorm yesterday and they mentioned your project where Velox/Internorm were being used together. We also discussed how heavy windows/doors would be supported on Velox. I am interested to see that you used steel plates (as described above) but I am wondering why you didn't rest the window on the concrete core closer to inside edge of the wall ? Was that option explored ? Also, isn't there a cold bridge if you use steel bracket ?

Thanks

Tim

 

[D Walter]

On 15/05/2019 at 17:11, Tim Alsop said:

Thank you. Since this thread is about Velox and I am planning to build my house using Velox, can you share how you fixed this onto the Velox board ?

Hi Tim, sorry about the delay - I am just back from a cycling trip in France.  The lay-up is:

1- breather membrane (Tyvek) stapled to Velox

2- battens

3- 18mm OSB

4- breather membrane (Tyvek) stapled to OSB

5 - Tata

[D Walter]

On 17/05/2019 at 10:13, Tim Alsop said:

Hi

I had a meeting with Internorm yesterday and they mentioned your project where Velox/Internorm were being used together. We also discussed how heavy windows/doors would be supported on Velox. I am interested to see that you used steel plates (as described above) but I am wondering why you didn't rest the window on the concrete core closer to inside edge of the wall ? Was that option explored ? Also, isn't there a cold bridge if you use steel bracket ?

Thanks

Tim

 

Hi Tim,

 

There are a few reasons why we did it this way and I will try and work through them. 

a) there is an optimum point in the thremal profile of the wall for the windows to be placed in order to minimise the risk of condensation.  Unfortunately we did not have a thermal image profile for the walls but Internorm estimated that it was a certain distance in from the outside and this was directly above insulation and not above the concrete core;

b) if the windows (which have a u value of c. 0.75) are above the concrete core of the walls (which have a u value of c. 0.15) and not the insulation they will themselves act as a thermal bridge;

c) visually the window reveals look better at less than the 215mm plus cladding depth which would have been needed in order to have the windows resting on the concrete core and there is less opportunity for seagulls etc to use the reveals as a platform.  On the Continent they tend to have much deeper reveals but they also often have to accommodate external roller blinds.

 

The steel angle supports for the windows will act as a thermal bridge  however we insulated the supports as best we could and their direct physical contact is only with the window frames themselves.  Everything is, after all, a compromise and we hope we got the compromise about right.....