Showing posts with label XPS. Show all posts
Showing posts with label XPS. Show all posts

Sunday, 15 February 2015

Week 15, 16 & 17 ( Jan 19 - Feb 6) ICF Walls

Work continued with the ICF walls.  The formwork for the window and door openings was put in position and secured with the plastic webbing imbedded the foam.




 The braces were also fixed the inside of the walls and screwed to the floor.  As the floor was being polished the number of screws in the floor was minimised as much as possible or located under stud walls.  In some circumstances, timber was screwed down to areas under stud walls and the braces fixed to the timber.  The wall braces also provide plank supports to allow work to be carried out on the upper parts of the walls.





 In a previous post the air tightness and thermal bridging of the fireplace was raised as a concern.  To minimise the thermal bridging the internal and external fireplaces were constructed as two separate structures with an 80mm gap between the two.  Into the gap an Intello membrane was added to ensure the air tightness layer continues past the fireplace.  This was embedded into the ICF walls at each end of the fireplace so that a tight join was achieved between the concrete in the ICF and the Intello fabric.  On the outside of the Intello 75mm of XPS foam is installed to provide continuous insulation from the ICF --> Fireplace --> ICF.


Below show the Intello in place with the first piece of XPS installed.


 The plumbers returned to site to install the sewerage pump tank, grey water system and fix the retaining wall that was undermined by the sewerage tank hole.



They also dug the trench down the slope to the water tank.  The power and data cables for the pump and shed were also laid in the trench.  The roots from the surrounding trees formed a damaging obstacle course will laying the pipe and conduits.  Note the flexible pipe used for the stormwater to be tolerant of any land slip issues over time.



The trench continued past the tank and connect to the legal point of discharge half way along the back fence.  The total length of the trench was approximately 70m.


Back on the ICF walls, Intello membrane was sandwiched between the top blocks of the ICF walls.  This was done to ensure an airtight connection between the concrete in the walls and the membrane that will be installed under the roof rafters.    When the ICF walls are core filled the membrane will be encased in concrete.



On the inside (of the thermal envelope) of the wall the membrane will be folded up and taped to the membrane under the roof.


Some of the wall are ready to be filled.


The short block wall near the Alfresco was completed - also ready to be core filled.


Conduits that are to be imbedded in the wall are sealed to the Intello membrane. In this case the conduit start and finish was within the thermal envelope but due to the way the blocks fell, the membrane was below the top penetration of the conduit and needed to be sealed to the membrane.




Other conduits were embedded into the walls to save chasing the foam later.  But as these conduits were in the garage (outside the thermal envelope) they did not need to be sealed.


Finally, after a number of delays the day (Friday 6th Feb) came to core fill the walls.  But as the first concrete truck did not arrive until 10.30 and the day was 35 degrees. There were a lot of stress and issues on the day, hence not many photos.


The fireplace was also filled.


After 12 hours on site (6pm), and 8 hours of core filling we had a block blowout, which dumped a cubic meter of concrete on the floor.  It would be another three hours before we finished for the day, unfortunately without the job complete and more core filling would be needed on Monday.













Sunday, 18 January 2015

Week 9 (8-12 Dec 2014) Concrete Slab Pour

The weather has not been helpful over the weekend and meant that the we were unable to get the slab ready for pouring on Tuesday. However, we were good to pour on Wednesday.


The floor box for a power point in the lounge was mounted so it was flush with the surface of the slab.  A hole was dug under the location and the XPS foam formed a continuous layer of insulation around the box. 


Spare FRP dowels were hammered through the XPS insulation into firm ground.  The dowels provide a solid base with little thermal bridging.


Additional temperature sensors were added directly above the previous sensors mounted at the base of the piers.  This will allow a measurement the difference between both sides (above and below) of the XPS




Wet area earth bond and Kordon termite barrier




The first slab ready to pour








A small rain shower arrives after the slab screeded.  Fortunately, it was only a small shower and did not cause any damage.




The next day the slab had cured enough to setup the other pours.  The formwork was removed from the construction joints and Intello membrane taped to the previously poured slab. This is to provide an airtight barrier when the join expands and contracts.





A pocket of intello is left to allow movement after the second slab is cured.



In the areas where the garage slab sits on the main slab, there is 20mm polypropylene packers to provide a thermal break as the garage slab is outside the thermal envelope and not insulated.  Also, more of the FRP dowels are used to reduce bridges.  The packers have an approximate R value of 0.7.





Pouring garage slab.



Sunday, 7 December 2014

Week 8 (1-5 Dec 14) - Underslab Insulation, formwork

Installation of the XPS foam began on the weekend in very hot (for Melbourne) conditions.  The detailing of how the XPS foam was to be installed was not well defined and practically became extremely difficult to come up with a workable solution.

What should have been installed

The initial concept for the build was to put the foam on top of a structural slab with a further screed slab on top.  This would have allowed for a very simple installation of the insulation with minimal thermal bridges.  Unfortunately, the structural engineer persuaded us to use a single slab on a cost basis.  In reality, the original concept would have been less expensive and much simpler to implement.  Lesson learnt!

What was installed



The issues were as follows ;
The foam was not self supporting and needed to be pegged in position.  As the raised elements of the  slab i.e. the bits between the beams was not precisely cut, because in a normal slab the concrete fills the voids the foam had to be backfilled to prevent the foam being pushed in when the concrete was being poured.  This caused another problem as before the concrete is poured there is nothing to support the backfill.  Various attempts at finding a solution were tried and failed. Finally, it was decided to leave pegs in place under the waterproof membrane that keep the foam in place.   unfortunately this adds a thermal bridge through the foam in the bottom of the trench and creates a void between the concrete and the XPS.

And yes, the XPS was suitable to be placed below the damp course layer.  According to the manufacturer's specification a typical reduction in insulation of performance of 0.6%(by volume) can be expected due to water  ingress.  (see - http://www.knaufinsulation.com.au/media/1000777/climafoam_xps_board_datasheet_web.pdf)

The sequence of events for the foam installation are as follows;

1/ Foam is cut and placed around the sides of the beams - in this case either side of a construction joint.  The tops of the piers are exposed.

2/ XPS is added to the area between the piers and sand is backfilled behind the foam to stop the concrete from collapsing the foam inwards.

 3/ Top sheets are laid out and pier locations are marked so they can be cut to expose the piers

 4/ We started cutting the piers holes in the XPS with a hot knife but found a simple jig saw with a long blade was faster and provided a better finish.


5/ The damp proof plastic is then laid over the XPS and cut to expose the piers

 6/ The piers holes are then sealed to provide a continuous damp proof layer

7/ Around the outside edge of the slab the first layer of ICF foam is nailed to the inside of the form work.  This becomes the start of the ICF walling system and provides the insulation for the slab edge.
The ICF supplier is Ecoblock (http://www.eco-blockaustralia.com.au/) - sold via Polycon (http://www.polycon.com.au/) in Victoria. 


8/ Where dowels are required in the edge beam piers a pultruded fibreglass dowel is used to reduce thermal bridges between the ground and edge beams. These dowels are 20mm and manufactured by V-Rod and supplied by Inconmat (http://www.inconmat.com.au/) in SA.

9/ The ICF corner profile is thicker than side wall

Other ICF suppliers worth consideration;