Thursday 9 April 2015

Slab Preparation. Day 3.

I arrived just before 3pm on Thursday to find that significant progress had been made. The polystyrene waffle pods had been put in place. The gaps between the pods form channels where the concrete will drop down into, giving strength. Concrete can take huge compression stress. Concrete does not deal well with tensile stress. To assist the concrete do deal with tensile stress, steel mesh and reinforcing rod is placed within the concrete to take the load. Most of the thicker reo-rod was placed in the channels. The mesh is lifted off the waffle pods, to be in the top third of the concrete. Both the guys laying the slab out, and the independent inspector where quite taken aback and surprised by the engineering of this slab. The slab itself is simple, as in not involved, but it is very heavily engineered. Heaven help anyone who wants to demolish this slab!
 
The initial laying out of the mesh on top of the waffle pods.


The mesh being lifted off the surface of the waffle pods. This also shows the width of and the depth of the solid concrete around the edges of the slab.


View from the front showing the garage and portico.


Closer inspection of the edge and corner.


The extensive bracing put in to support the slab.


Detail showing the reo-rod on the bottom being lifted off the bottom of the slab so that it's actually in the slab itself.


Detail showing the cross bracing in the narrower channels.

All of the supporting struts to support the boxing around the edges of the slab are manually put in place. Nailed, drilled or screwed into place. The mesh is put down, manually, and then lifted, manually, onto the round plastic supports shown above. These supports give the proper clearance above the waffle pod, and below the surface of the slab. It is a huge amount of work to be done. It is all manually performed, and by the end of the day, having been bent over for most of it, they are quite well exhausted. It's not a job that I could do.

It was at this point, before the pour (tomorrow) that we had David from Darbecca inspect the slab preparations. He was very pleasantly surprised that there were very few faults in the installation; all of which are only generally rectified (waffle pods that had moved etc) on the day of, or as the pour occurs.

I would also like to thank Matt, PD's Slab Mgr for being so approachable and responsive. I did not get the inspection report until about 7:30pm, and it was only then that I realised that I only had Matt's phone no, not his email address. I needed his email address so that I could forward the report to him. Matt was responsive to SMS's at 8pm at night, and I forwarded him the report. I could not ask for more!

So all in all, we're happy and excited about the pour for tomorrow!

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