Icf insulation

[Russell griffiths]

So I seem to have done a complete about turn and moved away from timber frame to icf, so re,doing a lot of research. 

First question icf are available in different insulation widths anything from 50mm to 150mm with obviously different u values, but also you can have a thinner standard block and add additional sheet eps to the outside to increase overall thickness. 

 

So the question is what would be the difference between using a thicker block in the first place as opposed to a thinner one and adding additional sheets to the outside? I'm trying to come up with a benefit of adding the extra and all I can think of is bridging all the block joins with a larger sheet May in someway prevent heat loss. 

Any thoughts. @Stones

Edited September 16, 2017 by Russell griffiths

[Stones]

@Russell griffiths There are a couple of critical variables to consider, time and money, and only you can determine your priorities.  

 

I have actually discussed this with my builder, and even taking into account the labour and other associated costs of fixing additional sheets to the face of a standard block, he advised that it was still more cost effective for him vs buying a thicker block which cost more to buy. Whether that's true for all ICF systems, I don't know. Transport costs also play a part.

 

I doubt there is going to be much of a difference in overall heat loss performance either way.

[jamiehamy]

Hmm, can't see a real benefit here unless you need to penny pinch or chasing a golden u-value. 

 

Difference between 150mm(100+50) XPS icf and 200mm (100+100) is £10m2.

 

I worked out a £5m2 for Recticel foil faced 50mm board. Add in long screws and time, I can't see this being advantageous tbh. Don't forget time overall - could easily be best part of a week for one person doing this. 

 

There is not time premium on thicker icf boards. 

[ToughButterCup]

2 hours ago, jamiehamy said:

Hmm, can't see a real benefit here unless you need to penny pinch or chasing a golden u-value. 

 

That's all that needs to be said.