I have to ventilate the space under the ground floor in the house that I am about to build and will do this by putting sleeves with grilles on through the ICF wall.  I am a bit worried that if I put a rectangular sleeve through the ICF wall then (a) I won't get a complete concrete fill under the rectangular sleeve and (b) that the wet concrete might crush the sleeve (the ones in the UK are designed to be built into masonry walls and are made of plastic).

How do you get round these issues?  One answer would be to put circular ventilation holes in the walls rather than rectangular as the concrete would flow round these more easily. 

I have read on here that the "standard " way to handle service penetrations is to put in a sleeve that is slightly larger than the required service pipe.  Do you do the same with ventilation holes as well? 

Thanks for your help.

Andrew

Andrew use round pipe for the penetrations. Make sure that they are large enough or numerous enough to provide the required amounts of ventilation space required by codes.
You can use the traditional rectangular units mounted in your finish exterior (stone or brick?) in front of the round penetrations as a finish piece.

Posted By aa_uk on 17 Aug 2010 03:29 PM
I have to ventilate the space under the ground floor in the house that I am about to build

Have UK building codes and practices yet recognized the advantages of sealed and conditioned crawl space? If that is accepted by UK building officials take a good hard look at doing that rather than ventilating the crawl space as you are now planning. Saves money and gives a better performing energy envelope for the house.

Thanks for the replies guys. The holes will be round.

UK building code says that we have to ventilate.