Tuesday, July 26, 2011

Airtight tape and shutter blowouts

This weekend saw the roof areas being poured with concrete (over the insulation and DPC).  Unfortunately though there was a problem - the shuttering parapet didn't hold and blew out.  They started on the small area first and when that went the larger area was left.  Its messy, and puts more delay on getting it done.  The issue wasn't the wood shutters, or the ICF plastic tie in points, but the screws that were used to hold it in - they snapped.


Hopefully we'll be back on course to get another try with reinforced shutters tomorrow.

On the inside, the detail around the window and door openings continues - I poured concrete behind all the window sills on the top floor (so no more lugging buckets of concrete up there!) and have the basement and 1/2 the middle floor left to do.  I also started taping windows where I've poured the concrete.  I'm using a SIGA tape - its expensive stuff but its well designed for the job.

The tape sticks around the edge of the window frame and across the gap onto the wall reveal of the ICF.  This gap is filled with foam by the window installers, but that foam isn't airtight, so its a source of drafts and in winter that means cold air pouring in.  So the edge of every eindow and door needs to be taped up.  Its fiddly work with a small knife, and the tape is super-sticky, so your fingers get all glue'd up.  Also, sinve the gap between the window and wall is never uniform you end up having to patch parts of it - its not as easy as the guy in the video makes it look!


Here is the window tape - Corvum 12/48.  The window is sealed, but I also need to add tape to seal the inside EPS to the reveal - once I cut the metal window pins back to the minimum size.

As well as the windows, anywhere a pipe exits the building is a source for unwanted air to come in.  The key is to try and only have the MHRV as the source for air in the house - that way all the air coming in is pre-warmed.  Rissan tape is used on the pipes - and if the window tape is super sticky this stuff is unbelievable.  I'm like a football commentator running out of superlatives.

Here's some of the Rissan on a 4" waste pipe


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