Blog #4: The Pour.

The slab pour got delayed 1 day due to forecasted rain, and the call was spot on. So, Saturday was the big day, probably unusual to pour on a weekend but I guess Saturday has become a free day with the cancellation of sport.

I experienced some pre-game nerves on Friday night, still worried about the weather and not really knowing the implications, and concrete is so finite – once it’s down it is down and we only get one go at this!

We are having an exposed concrete edge on our slab and want a nice straight and smooth finish. There is no brickwork or rebate and our footpaths will be set down so there is nothing to hide any bowing or imperfections. So, I guess our slab was a bit trickier than normal.

It also did not help that I left setting up the time lapse camera until the night before, so had to do so in the mud and dark without knowing how the thing worked.

Other items to note with our slab are:

  • 150mm step down to our garage. Most houses now a days do not have a step down to the garage, however I wanted one to reduce the height or garage wall and have the driveway lower.
  • Recess for sliding door tracks so there will be no step to our deck. This is achieved by placing a timber mould on the edge of the slab
  • Recess for showers so screed (sand cement mix) can be added at later date and graded to the floor waste to create a stepless tiled shower base. This is now standard practice.

I did not sleep particularly well, mainly through excitement and woke at 3:30 and 4:30 just wanting to get up. I held off until 6:30 and we got up to go for our usual Saturday morning walk and coffee. We swung past the block and saw Kristian (builder/brother) who was there helping Grub (concreter Ashley McKnight) with the finishing touches before the 7:30am pour.

By the time we returned the site was a hive of activity. There seemed to be trucks and tradies everywhere. I called in took some photos, chatted to Kristian and took stock of the whole process. Jess went home to grab the kids who then came for a look.

Concrete trucks arrived at the site one after another (9 loads for our slab) and unload into a concrete pump. The concrete pump is on the back of a truck that parked at the front of the site. The concrete is pumped through a remote controlled articulated arm (called a boom) to where it is required.

A team of concreters (8 in total) armed with shovels, screeds and a level then spread and levelled the concrete a section at time. Grub and his wife Kelly were on the outside vibrating the edges, levelling with a bull float (tool used to finish concrete surfaces) and overseeing the whole operation.

Once it was all poured and levelled they then waited until it set a bit before getting on the slab with an automatic trowelling machine (known as chopper).

In cold weather the concrete goes off slowly, additives can be added to help it set. In hot weather it goes off too quick so additives can be added to slow it down. I think colder weather is preferable as it allows more time to get it right, however, can mean more waiting and a longer day.

We are having polished concrete and to achieve our desired finish our polisher requested that the concrete was burnished very flat. This is achieved by extra work on the chopper, so Grub had a long afternoon and well and truly earnt his Saturday night beer! I did not earn my beers but had some anyway to celebrate.

On Sunday morning we called into the site, and Grub was back to take down all the boxing. He told us that it would be ready to walk on later in the day, so we brought the kids back for a look around lunch time and did a walk through.

I was aware that slabs always seem small without any walls up, so I pre-warned Jess and the kids that it may seem small, but assured them that it will be big enough…

The exposed concrete edges came up a treat, and McKnight Concreting have done a fantastic job. They achieved the nice smooth finish by using MDF sheeting on the inside of the boxing.

Marco Tesmer from Tesmer Concrete is there today (Saturday) to do the first cut of the floor polish. Again, unusual for work to be happening on the weekend, and hopefully I am not paying Saturday rates! The word from the site is that Marco is pleased with the slab, it is nice and flat, and we should get a good result with the polish.

The slab polish will likely be the topic of a future blog, so will discuss in more depth then.

Pics and footage below. Have a great day everyone ✌️

Wilson Court Build – Slab Pour

Some great work by McKnight Concreting. Blog to follow soon…#wilsoncourtbuild

Posted by McKnight and Bray Building Design on Friday, 10 July 2020

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