ICF Queries/concerns from Architect/Structural Engineer

[Alexphd1]

Still working on it. 

 

I initially thought we could just K-rend rite over dpm course but render guy said no. We are now considering using something like this bay window connectors    http://spectrumarchitectural.com/aluminium-window-cills-and-pressings/

Kicking out 60mm at dpm course for a 40-50mm sandstone (denfind stone)facing stone plus 10mm adhesive to match other parts of house. 

 

Next house probably  raft upstands 200mm thick with 250mm thick external eps icf so 50mm overhang for stone work. Just a idea but will investigate further...... best laid plan?

Edited October 17, 2018 by Alexphd1

[Adam2]

@Alexphd1 What was the reason for not rendering down past the dpm? My last house was rendered (traditional not acrylic etc) and that was down to paving level around the house

[Adam2]

Thanks so much for the great information and food for thought. My views are below, will evolve as we get more professionals involved and you guys /girls of course ?

 

On 17/10/2018 at 09:39, Adam2 said:

• The main concern on this project would be the waterproofing system.  With an ICF product, how would the product be guaranteed?  Typically the crack widths would need to be no bigger than 0.2mm.  These are controlled by the amount of reinforcement and the cover to the reinforcement.  With ICF both the amount of rebar that can be incorporated with the wall and the cover tend to be fixed or difficult to change.  How would the walls be checked to make sure that 0.2mm crack widths have not been exceeded.
• The house has a lot of large openings.  These could be difficult to prove using ICF due to the fixed width of wall.  There are only so many bars that can be placed within a certain width of wall.  This could mean that steel beams and or columns are required, causing further issues with detailing around the interfaces between the two.
• Care needs to be taken when installing kitchen and bathroom units as the fixings need to be taken through the polystyrene and into the concrete.  The insulation could compress causing the units to be un level and out of alignment.
• Detailing of structural elements can prove difficult trying to comply with the detailing code. 
• The system is advertised as low level skill required to construct the system but in reality tying of rebar and pouring of concrete are skilled jobs and need skilled labour to carry them out.

 

Waterproofing - agree, it's a challenge and ICF means you can't check quality of concrete - hard to know how real an issue that is. If you waterproof the outside of the ICF then that should be less of a concern. Plenty of houses on hills even with ICF so will note this as a concern and will apply a lot of focus on this during design to ensure appropriate solution and warranty

though using your warranty in this scenario is never going to be a happy outcome!

 

Large openings - not concerned too much, you can use wider ICF if the requirement is more rebar and beams if needed. Anticipating hollow core for the largest non-slab bearing floor area and timber for upper floor to mitigate weight. See what SE (with more ICF experience) has to say.

 

Kitchen/bathroom fixings - surely you use structural OSB or bracing behind plasterboard ? Not concerned

 

Detailing - seen plenty of ICF houses with a sharp/contemporary finish so not concerned

 

Skills levels - we are not building ourselves, will select an experienced ICF builder and SE. Though will be keen to monitor what is happening ?

 

Great feedback, plenty to think about. Next step is selecting SE and finding ground investigation co/conducting that pre meeting with SE and architect to kick off the detailed design. For sure will be back to read & post more questions!

 

 

[mvincentd]

11 hours ago, Adam2 said:

If you waterproof the outside of the ICF then that should be less of a concern.

Maclennan (for example), (using Newton waterproofing) refused to waterproof externally and would only do an internal cavity drain system.  This is what most of the houses further along from you on Banks Road use where it's an extreme case of sea on both sides and built on sand!  Basically the system admits defeat, lets water in, but then guides it away.....all of which is going on just behind your plasterboarded walls.  I hate the thought of it but by all accounts it is effective.

 

I am happy with my experience of using Godsel Arnold Partnership... @vivienz dealt with them too, I don't know her final opinion...they're local to you, Broadstone.

[vivienz]

6 hours ago, mvincentd said:

Maclennan (for example), (using Newton waterproofing) refused to waterproof externally and would only do an internal cavity drain system.  This is what most of the houses further along from you on Banks Road use where it's an extreme case of sea on both sides and built on sand!  Basically the system admits defeat, lets water in, but then guides it away.....all of which is going on just behind your plasterboarded walls.  I hate the thought of it but by all accounts it is effective.

 

I am happy with my experience of using Godsel Arnold Partnership... @vivienz dealt with them too, I don't know her final opinion...they're local to you, Broadstone.

 

Mostly nice people to deal with but, in my experience, always seemed to opt for the most expensive solutions which I didn't use as there were lower cost and equally effective ones available. This was particularly the case with piling.