Skip to main content

Lets Try This Again: A Well Insulated Slab

Time was ticking and we ran out of 2" type II EPS.  Luckily our local building suppliers carry a small supply of 2" 2'x8' Foundation Plus.   The next morning we finished up placing the foam.  Pipe and conduit penetrations in the foam were cut slightly oversized to allow some room for aligning the foam pieces together.  After the foam was laid, we spray foamed around the pipes (Photo 1-1).  This serves 2 purposes:  The first is to insulate, the second is to stabilize the pipes during the cement pour.

On to the next task:  Vapour barrier, air sealing, and rebar!



Comments

  1. Anonymous21 June 2017 at 19:57

    Did you go with 10 in insulation, and is your garage insulated to the same standard
    Winston

    ReplyDelete
    Replies
    1. David J. Goodyear22 June 2017 at 01:06

      Hi Winston, it's been a while! Hope all is well. There is 10" of type 2 eps under the house slab with the exception of the thickened rebar reinforced section in the middle. That section has 6" of type 3. I wanted a well insulated garage so we went with 4" under the garage slab. There is also a check poured into the foundation wall at the top so foam could be added in order to isolate the garage slab from the foundation walls. The garage walls will be insulated to r20 with batt but there is 3" of eps to the outside. I think the effective r value works out to be about 28 but I would have to calculate to confirm.

      Later!

      Later

      Delete

Post a Comment

Popular posts from this blog

Building the Air Tight Barrier: Door Flashing Details.

It took us a while to wrap our heads around the door details on my plans.  The main exterior wall is composed of 2x8s.  The rough stud opening was substantially larger than the door.  Because the walls are much deeper than a standard door frame for a 2x6 wall, the interior of the 2x8 opening was studded with double 2x4s.   Outside of these 2x4s, there is 1.5" of foam and another 2x4 on face which brings the door frame opening flush to the exterior 3" of EPS foam.  The brick mould of the door will sit against the exterior of the wall.  The ganged 2x4s which define the opening will allow the door to open a little further than that of a 2x8 wall.    With the door details finalized, I had to flash the opening as per the plan.  I specified the size/shape for aluminum sill pans and CBS Eavestroughing made them for me.  The sill pans have a kind of end dam to prevent water from entering under the under the stud opening should the door ever...
3 comments
Read more

The Attic: A hatchway, A Landing and a Catwalk.

  Attics are one of the neglected spaces in the our homes....an afterthought really.  Many trusses are designed the same way they were years ago.  There is no thought put into the lack of insulation above the top plate on exterior walls.  Heeled trusses were developed as a solution to this problem (https://www.apawood.org/raised-heel-trusses).  Adding a small heel enables deeper insulation over the top plate of exterior walls and helps prevent thermal short circuiting to and from the attic space.   It seems that heel trusses may become a mainstay for the future since new code changes now required attics to be a minimum of R50.  Large heels mean more blocking and higher baffles to combat the effects of wind washing on the thermal effectiveness of the attic insulation.  The key here is to direct any wind (entering the attic through the soffit) far above the layer of insulation.  The air contained in the insulation remains stagnant which ...
Post a Comment
Read more

OSB, OSB, everywhere...

In the previous post we were installing the OSB air barrier on the 2x8 stud walls.  The drawing specifies that OSB be installed on the interior of the 2x8 stud wall. Once all joins are caulked with acoustical sealant and then taped, the OSB will act as an air barrier and will also serve as a vapour retarder. Before attempting to install OSB on the ceilings we narrowed down our game plan.  We quickly decided that lifting heavy sheets and attaching them to the ceiling using muscle power and a dead man support was out of the question.  Our local Princess Auto had a drywall lift on sale so we bought it.  We started in one corner of the building.   One person on a ladder guiding the other where to push the drywall lift loaded with a sheet of OSB worked great.  Our first sheet was cut so that the edge of the sheet could be nailed under the underside of the truss.  Using a framing nailer armed with 2 3  /8" nails was the way to go for attaching the she...
Post a Comment
Read more