ICF Started

The first blocks of ICF are now going onto the basement!  These blocks are forming the front-outside walls and main load-bearing internal walls of the basement.  With these up, we'll be able to walk inside our house for the first time.

The blocks arrive flat-packed from the factory and open up with the plastic internal ties locking them into shape. These are then stacked like lego and steel bars places along them for reinforcing the concrete.  For door and window openings the blocks are simply sawed into the lengths.  No morter or glue is required to hold them together, the blocks fit via a set of plugs on top and sockets on the bottom in a snug fit.

The gap between the polystyrene needs to be shut at the door and window openings, lest the concrete pour out!  Another piece of polystyrene slots between the 2 layers facing into the gap.  Some ICF systems just use wood either, and this has the same effect, the only difference is that the polystyrene sleeves have a better insulation, and it's at the door and window joins that you get a lot of issues with cold-bridging and drafts.  Drafts can be sealed with an expandable foam insulation, but cold-bridging is harder.. its where a conductive material (such as metal) runs from the inside where its warm to the outside where its cold.  This creates a conductive bridge between the 2 environments that bypasses the insulation layers, and leaks heat at a high rate.  It's tricky as where components join it's very easy to create a bridge unknowingly.. an example might be if screws from the inside were to connect to brackets that hold in the windows, and the bracket were to be on the outside.  Its the detail like this that can turn a warm home into a cold one.  In designing the house, there are lots of places these can creep in, and then all it takes is a tradesman to take a short cut and you leak heat (and money!)

So this week should see the build and pour of the basement sections.  I managed to procure a number of ducts from the HRV supplier to place into the walls before we pour the concrete, we'll also add a couple of other 6" or similar ducts to allow electrical cabling and the central vacuum to route through.  This will save drilling through the concrete later (if we've thought of everything).

So far we only have some of the walls complete, waiting on confirmation of the window sizes to properly construct the walls.

The weather right now is fantastic, long may it continue!!  In other news, the bank has re-approved our mortgage and once we re-sign updated documents we should be able to start accessing the money - a massive weight lifted off my shoulders on reading that.