MTC

New Self Build

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In process of buying plot and looking at building a ICF barn clad in timber. 

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Anyone got any advice on using ICF blocks

 

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Posted (edited)

Welcome along. 

 

Find a structural engineer who understands ICF. Our SE recommended by our architect has used enough rebar to support a suspension bridge!! It shouldn't need much or any according to the manufacturer but SE's tend to err on the side of caution.

 

Try and make it a design where there is little or no cutting of the blocks. We are using Polysteel ICF which only come in one length. A simple square or rectangular design suits it best. Ours is rather more complex meaning that there is more bracing/shuttering for the concrete pours. 

Edited by Happy Valley

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8 hours ago, MTC said:

Anyone got any advice on using ICF blocks

 

Search Durisol on this site. 

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9 hours ago, MTC said:

In process of buying plot and looking at building a ICF barn clad in timber. 

 

Have a look at Velox http://icfsystems.co.uk/. The major problem with a block woodcrete ICF system (Durisol, Isotex, etc) is that they have gaps.

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3 hours ago, Adrian Walker said:

 

...The major problem with a block woodcrete ICF system (Durisol, Isotex, etc) is that they have gaps.

 

Could you explain the comment about gaps, please @Adrian Walker, thanks. Could you explain; where the gaps occur, the extent to which the gaps are problematic, and if it is possbile to remediate the gaps?

Ian

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The Polysteel Warmerwall that we are using doesn't have any gaps. They are glued together and use clips between the built in wire mesh. The window and door openings are shuttered with wood and braced.

 

If there were gaps how do you pour the concrete??

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Posted (edited)
14 minutes ago, Happy Valley said:

...

If there were gaps how do you pour the concrete??

 

Precisely the question that I asked,  spent about a week investigating. I'm on a phone now, when I get back to the office I'll dig out some photos,  and come back. 

 

The short answer is that gaps up to about 15mm mend themselves during the pour: the stone jams itself in the gap. Bigger gaps need a bit of old board screwing on the outside, and the pour jams itself tight in the gap there. 

 

I'll be interested to see what @Adrian Walker has to say on the matter.

Edited by ToughButterCup
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Here you are: some gaps caused by the usual issue - lack of care with the blocks : dropping one on the corner, or poor product handling. This image was taken after the pour.

As you can see concrete hasn't leaked. 

So, foam gun in hand,  I beetled round after the pour shoved some foam in where  I thought the gap was excessive. As this photo shows, I missed some bits

To the extent that my limited experience of one ICF is correct, gaps, if they occur are all remediable.

 

There is no good reason to state that all Durisol has a problem with gaps and (and is claimed above) no grounds whatever to say that, where they occur,  gaps are a major problem.

gaps.thumb.jpg.e5ff858df96031861ac2384fc8259c0d.jpg

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15 hours ago, MTC said:

Anyone got any advice on using ICF blocks

 

Do your own research. 

Im currently working on 3 icf houses, they all have their faults. 

Some issues are bigger than others. 

Cold bridging at reveals, poor airtightness, inaccurate blocks, hard to cut. 

The list goes on and on, you need to decide what items are ok and what needs major remedies to make a better system. 

And do not listen to the salesman, you want a rep who doesn’t care if you buy his blocks or not, he gets a sale by the product not his fast talking. 

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54 minutes ago, Russell griffiths said:

...

Some issues are bigger than others.  ... inaccurate blocks,  

...

 

For us, inaccuracy was the biggest issue with the second batch delivered. And I think that large demand for the product was the pressure that caused quality to slip. I went to visit another build after ours was finished: the quality of the blocks was noticeably better.

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2 hours ago, ToughButterCup said:

gaps.thumb.jpg.e5ff858df96031861ac2384fc8259c0d.jpg

If Durosol made cars or boats, life would be so much better won't it.

15mm gaps FFS, what is that about.

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Posted (edited)

Bad day @SteamyTea ?

In one or two places (where I laid the blocks) there are 15mm gaps, which didn't matter, because the 10mm chippings in the mix blocked the gap easily.

I am no sales person for Durisol: it's one of a few similar products. But it shouldn't be criticised on the basis of my unprofessional work. If memory serves me right, I was totally knackered while building the parapet along the top of our flat roof - the 'outside' temperature there is always the same as the 'inside' .

 

Had the gap been 30mm, it would not have mattered.

Edited by ToughButterCup

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1 minute ago, ToughButterCup said:

Bad day

No, I the sun is out and my customers have been well fed, for now.

 

I just find it strange that the tolerances on building components is so appallingly bad, it would not be acceptable anywhere else (in catering, we generally buy by mass, not mass plus of minus 250g).

The ignorance of new technique is also staggering.  Guy who fitted my neighbours new windows did not understand the concept of airtighness, or MVHR.

Very few of us on here can agree on the best heating system for a house, and people still talk about woodburners, a 2 million year old technology.

Customers have to insist on getting what they want, then the industry needs to step up and supply it.

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59 minutes ago, SteamyTea said:

No, I the sun is out and my customers have been well fed, for now.

...

 

Excellent.

Now, off to cook HerInDoors' supper.  Grilled goat's cheese and steak burritos. Trying to keep the cooking-disaster-level low this week. 😔

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Posted (edited)
6 hours ago, ToughButterCup said:

 

Could you explain the comment about gaps, please @Adrian Walker, thanks. Could you explain; where the gaps occur, the extent to which the gaps are problematic, and if it is possbile to remediate the gaps?

Ian

 

As ToughButterCup showed the blocks butt up to one another and create a small gap between them.  I have often seen daylight looking out before any coating (plaster, render, etc) has been applied. The woodcrete insulation is good, but just like a woolly jumper you also need to wear a windcheater to get the full benefit of the insulation.  Velox uses woodcrete but has a continuous concrete layer and hence before any coating has a much better airtightness. The biggest loss of heat in a house is air convection currents caused by poor airtightness. 

Edited by Adrian Walker
Typo

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